Beta Glucans: What are they really?

Mushroom extracts are all the craze today. Have you ever wondered what are in these extracts? What do you as a consumer look out for when you buy a product? The answer to these questions is not very simple as there are an array of different bioactive molecules which give mushrooms their functional benefits. The three main classes of biomolecules being- polysaccharides, terpenes and phenolics.  In this blog we will delve deeper into the world of polysaccharides, an important class of compounds that are responsible for giving mushrooms a lot of their healing properties. However, please do keep in mind that all polysaccharides are not the same, as we will see later in this blog. Our primary focus here will be Beta glucans, which are the main functional components of mushroom polysaccharides. 

In our previous blog we had a look at the intricacies of the fungal cell wall. The three major layers (Chitin, beta glucans and mannoproteins) are intertwined into a dynamic barrier that has stood the tests of time and allowed fungi to thrive (See Figure 1). Having evolved with fungi for billions of years, our immune systems recognize these cell wall components as a threat and spring into action. These molecules are what give mushroom extracts their immuno-modulatory function. A major active ingredient in these extracts are the beta glucans. They are polysaccharides that form the middle layer of the fungal cell wall (Layer 2 in Fig 1). 

 

 

Fig 1: Cartoon representation of a Candida albicans (yeast) cell wall (Source)

 

Beta glucans are incredibly diverse in their composition and function. Different mushrooms contain different beta glucan molecules. To fully understand these differences, we will be exploring these polysaccharides from a molecular perspective. 

In this blog we will deconstruct the polysaccharide molecule and understand how they are named. We will also explore some of the common beta glucans obtained from mushrooms and their health benefits. By the end of this blog we hope that you will have a much better understanding of what beta glucans are and what to look for in your own research.

Before we delve into the details of beta glucans, we must first understand the term polysaccharide.

What are Polysaccharides

Any molecule composed of long chains of carbohydrates strung together is known as a polysaccharide (“poly” = ‘Many’, “Saccharide” = ‘Sugar’). These chains are made of sugars called monosaccharides. The most common examples of monosaccharides are glucose, mannose, fructose, galactose and xylose. Our beloved table sugar is in fact made up of glucose and fructose. Each molecule of sugar (sucrose) consists of one glucose and one fructose molecule. Since there are two monosaccharides in sucrose, it is known as a disaccharide. When the number of monosaccharides exceeds twelve the molecule is known as a polysaccharide. 

Fig 2: Sucrose, a disaccharide made of D-Glucose and D-Fructose

 

Glucose: The building blocks of beta glucans

To understand how polysaccharides are named, we must first look at the molecular structure of a polysaccharide molecule. We start with the humble glucose molecule. Glucose is nature’s preferred fuel source. Almost all living things break down glucose within their cells to generate ATP (adenosine triphosphate) which is the energy source for biochemical reactions. 

Structure of a Glucose Molecule

Glucose consists of 6 carbon atoms, 12 hydrogen atoms and 6 oxygen atoms giving it the molecular formula of C₆H₁₂O₆. The carbon atoms are arranged in a 6-member chain with the oxygen and hydrogen atoms sticking out from the central chain. Every carbon atom is attached to at least one hydrogen atom and either an alcohol (-OH) or ketone (=O) functional group. The distribution of these functional groups determines the name of the monosaccharide. Glucose is specifically the 6- carbon monosaccharide which has an arrangement of atoms as depicted in the figure below.

Fig 3: Structure of a D-glucose molecule in the open-chain format

 

Many Forms of Glucose

If one were to change the orientation of the -OH and -H molecules on any of the carbon atoms, we would obtain a different monosaccharide. For example, galactose and mannose have the same number of carbon, oxygen and hydrogen molecules as glucose but with different arrangements. Such molecules are known as isomers. Hence, mannose and galactose are isomers of glucose.

Fig 4: Isomers of D-glucose depicted in the open-chain format highlighting the distribution of functional groups across each molecule

 

The Ring of Power

In reality however, these monosaccharide molecules do not exist as open- chains. The first and fifth carbon atoms in the chain fold over to form a hexagonal structure with the oxygen atom forming a bridge between these carbon atoms. This is the functional form of the D-glucose molecule. 

Fig 5: The folding of an open-chain glucose molecule to a hexagonal glucopyranose unit

 

What’s in a Name?

Glycosidic Bonding

Now that we have a basic understanding of the structure of the monosaccharides, we can begin to understand how they link together to form polysaccharides. The bonds that link these monosaccharide molecules to one another are called glycosidic linkages or glycosidic bonds. These linkages are traditionally formed between the alcohol (-OH) containing first, third, fourth or sixth carbon atoms. So when a bond is called a 1 → 4 glycosidic bond, it indicates that the first and fourth carbon atoms of adjacent molecules are participating in the bond formation. 

Alpha or Beta?

Another important aspect of the bond is its orientation. The roman letter alpha (𝛼) or beta (𝛽) are used to indicate this orientation. This can be better understood by considering the two disaccharides in the image below. Let us begin by imagining the ring to be a plane with the functional groups sticking out above and below this plane.

Figure 6 a) represents the link formed between adjacent D-glucose molecules in a Maltose molecule. The first and fourth carbon atoms of the adjacent glucose molecules partake in a 1→ 4 glycosidic bond. The (-OH) groups taking place in the bond lie on the same plane below the hexagonal ring structure. Bonds taking place in the same plane are termed 𝛼-glycosidic bonds. Therefore Maltose exhibits an 𝛼 (1→4) glycosidic bond between its two glucose monosaccharides.

In contrast Lactose molecules (Fig 6 b)) are linked through 𝛽 (1→4) glycosidic bonds. The (-OH) molecules from galactose and glucose that take place in this bond formation lie on opposite sides of the hexagonal ring structure. This bond therefore forms across this plane. 

Fig 6: a) The combination of two D-glucose molecules via an 𝛼 (1→4) glycosidic bond results in the formation of a Maltose molecule

b) The combination of D-galactose and D-glucose molecules via a 𝛽 (1→4) glycosidic bond results in the formation of a Lactose molecule

While this terminology can be rather confusing, the important thing to remember is that 𝛼 glycosidic bonds form on the same plane while 𝛽 glycosidic bonds form across two different planes. This difference contributes to very different three-dimensional conformations for the two kinds of bonds. 𝛼 bonds are more linear resulting in tightly packed structures as in the case of amylose (a component of cellulose), while 𝛽 bonds are more flexible and tend to rotate into helical shapes like in the case of chitin. 

Different kinds of beta glucans

The above examples demonstrate the different kinds of bonds that can form between monosaccharide molecules. However, when we talk about bioactive polysaccharides from mushrooms, we are specifically interested in beta glucans. 

Mushroom beta glucans are those polysaccharides that consist of glucose molecules linked together via 𝛽 (1→3) and 𝛽 (1→6) glycosidic bonds. This is an important distinguishing factor since beta glucans are also found in a wide variety of plant foods such as barley and oats.

These plant beta glucans consist primarily of 𝛽 (1→3) and 𝛽 (1→4) glycosidic linkages. The 𝛽 (1→4) linkages result in a more linear and packed structure. As a result, these plant glucans are harder to break down in our digestive tracts. They thus contribute to the beneficial insoluble fibers that nourish our microbiome.

Beta glucan diversity

Beta glucans are found in all fungi, including yeasts. Different fungi have different glucan compositions. Ascomycete fungi such as Cordyceps contain glucans that have varying amounts of glucose, galactose and mannose. Basidiomycete fungi such as oyster mushrooms, Reishi, Turkey tail and Shiitake have predominantly glucose in their glucan molecules with minor contributions from the other monosaccharides.

The ratios in which the different monosaccharides are found in the glucan molecules affect both their structures as well as their bioactivities. The different configurations and branching structures of beta glucans lead to differences in their effects on our health. These effects vary considerably from species to species. It is therefore not surprising that the species of mushrooms that have been used for medicinal purposes for the last two to three thousand years are also the ones which have the highest beta glucan content. 

We always recommend our readers to look for beta glucan content in their mushroom extracts. Polysaccharide content does not imply beta glucans.

Common sources of beta glucans and their health benefits

If you’ve ever consumed a mushroom, you have consumed beta glucans. Many of the health benefits of consuming mushrooms come from the beta glucans. As beta glucans are an essential part of the fungal cell wall (see blog), every cell of the mushroom contains beta glucans. This makes them very easy to incorporate into our diets. All we have to do is consume mushrooms, although some ways of consumption lead to better absorption compared to others.

Oyster mushrooms 

Oyster mushrooms are robust and easy to grow. They are a beginner friendly mushroom to try growing at home. They grow happily on almost any plant based substrate and are ready to burst out fruiting within a few weeks. (if you want to grow your own at home try our mushroom growing kits)

Fig 7: Pleurotus ostreatus (Pearl oyster mushroom) [image illustration]

Pleuran is a beta glucan isolated from Pleurotus ostreatus (Pearl Oyster Mushroom). It has been shown to have an immunomodulatory effect while also being beneficial for skin, gut and respiratory health. It also has antiviral activity.

Fig 8: Molecular structure of Pleuran, a 𝛽 glucan extracted from oyster mushrooms (Source)

Shiitake Mushroom

Shiitake mushrooms are another edible variety that is rich in beta glucans. It has long been consumed by cultures of the far East and is revered both for its culinary and medicinal properties. 

Fig 9: Lentinula edodes (Shiitake mushroom) [image illustration]

Lentinan is a beta glucan isolated from Lentinus edodes (Shiitake Mushroom). It has  potent immunomodulatory effects. This in turn promotes the body’s own anti-cancer, antiviral and antimicrobial abilities. It is one of the most well understood beta glucans. Its widespread use is restricted by the difficulty of extraction of this molecule.

Fig 10: Molecular structure of Lentinan, a 𝛽 glucan extracted from shiitake mushrooms (source)

Maitake Mushroom

The Hen of the woods, also known as Maitake in Japan, is well known for its delicious taste and aroma. However it is also rich in beta glucans that provide immunomodulatory, antidiabetic. antiviral and antitumor properties.

Fig 11: Grifola frondosa (Maitake mushroom) [image illustration]

 

Grifolan is a beta glucan isolated from Grifola frondosa (Hen of the Woods mushroom). It has strong antitumor activity.

Reishi Mushroom

Apart from edible varieties, most medicinal mushrooms are particularly rich in beta glucans. The Reishi mushroom, also known as the herb of immortality in traditional Chinese medicine, has a very high beta glucan content. These beta glucans are in part responsible for the legendary immunomodulatory properties of Reishi mushroom extracts.

Fig 11: Ganoderma lucidum (Reishi mushroom) [image illustration]

Ganoderan is a beta glucan isolated from Ganoderma lucidum (Reishi mushroom). It possesses antitumor, hypoglycemic, antioxidant, probiotic and immunomodulatory properties. 

Conclusion

Table 1: List of mushrooms with their beta glucans and associated health benefits

In this article we delved into the structural details of beta glucans. We took apart the differences between polysaccharides and beta glucans and looked at how the glucose molecule forms the fundamental building block for most beta glucan molecules of fungal origin. Finally, we explored some of the commonly studied beta glucans and the mushrooms they came from. 

Beta glucans are extremely diverse in their structure. No two mushroom species will have the same beta glucan composition. These differences allow the extracts obtained from different mushroom species to have different health effects. In recent years many clinical trials have been initiated to investigate the relevance of beta glucan supplementation. Traditional healers swear by the healing powers of functional mushrooms. Modern medicine is attempting to verify and specify the use cases where these fungi can have maximum impact. 

A major challenge lies in obtaining large quantities of pure beta glucan molecules. Only about 20% of the beta glucans are soluble without significant heating. Beta glucans consumed in the form of whole mushrooms are harder to digest. Extraction is a method of enriching beta glucans and increasing their bioavailability. 

Many mushroom extracts represent their concentration as ratios or in terms of polysaccharide content. These are misleading terms and do not indicate the effectiveness of the extracts. We always recommend that one checks specifically for beta glucan content when inspecting an extract for potential health benefits. Always remember that polysaccharides do not imply beta glucans.

Modern extraction methods aim to maximize and standardize beta glucan content per dose. In our next blog we will explore the latest extraction technologies and how they can help improve beta glucan yields.

References

Š. Karácsonyi and Ľ. Kuniak. 1994. “Polysaccharides of Pleurotus ostreatus: Isolation and structure of pleuran, an alkali-insoluble β-d-glucan”. DOI: 10.1016/0144-8617(94)90019-1

Milos Jesenak et. al. 2015. “β-Glucan-based cream (containing pleuran isolated from pleurotus ostreatus) in supportive treatment of mild-to-moderate atopic dermatitis”. DOI: 10.3109/09546634.2015.1117565

Ingrid Urbancikova et. al. 2020. “Efficacy of Pleuran (β-Glucan from Pleurotus ostreatus) in the Management of Herpes Simplex Virus Type 1 Infection”. DOI: 10.1155/2020/8562309

Juraj Majtan. 2013. “Pleuran (β- Glucan from Pleurotus ostreatus): An Effective Nutritional Supplement against Upper Respiratory Tract Infections?”. DOI” 10.1159/000341967

Yangyang Zhang et. al. 2011. “Advances in lentinan: Isolation, structure, chain conformation and bioactivities”. DOI: 10.1016/j.foodhyd.2010.02.001

Takuma Sasaki and Nobuo Takasuka. “Further study of the structure of lentinan, an anti-tumor polysaccharide from Lentinus edodes”. DOI: 10.1016/S0008-6215(00)83552-1

Yiran Zhang et. al. 2018. “Lentinan as an immunotherapeutic for treating lung cancer: a review of 12 years clinical studies in China”. DOI: 10.1007/s00432-018-2718-1

Hiroshi Hikino et. al. 1989. “Mechanisms of Hypoglycemic Activity of Ganoderan B: A Glycan of Ganoderma lucidum Fruit Bodies”. DOI: 10.1055/s-2006-962057

Hiroshi Hikino et. al. 1985. “Isolation and Hypoglycemic Activity of Ganoderans A and B, Glycans of Ganoderma lucidum Fruit Bodies”. DOI: 10.1055/s-2007-969507

Masashi Tomoda et. al. 1986. “Glycan structures of ganoderans b and c, hypoglycemic glycans of ganoderma lucidum fruit bodies”. DOI: 10.1016/S0031-9422(00)83748-6

Xue-Song Yang et. al. 2009. “Effects of Ganoderan on the dysbacteria in intestinal tract of mice”. DOI: 10.1096/fasebj.23.1_supplement.980.2

Weifeng Wang et. al. 2019. “Ganoderan (GDN) Regulates The Growth, Motility And Apoptosis Of Non-Small Cell Lung Cancer Cells Through ERK Signaling Pathway In Vitro And In Vivo”. DOI: 10.2147/OTT.S221161

Yifeng Zhang et. al. 2013. “Schizophyllan: A review on its structure, properties, bioactivities and recent developments”. DOI: 10.1016/j.bcdf.2013.01.002

Just like plant cells and unlike animal cells, fungi possess a cell wall. The cell wall is nothing but a protective layer within which all of the cellular components are housed. It acts as a protective shield that allows a fungal cell to carry out its functions without threat of destruction from external stresses. While it is easy to think of the cell wall as just a hard shell like that of a tortoise or turtle, this could not be farther from the truth. The cell wall is a highly dynamic and responsive organ of the fungal cell. This dynamic organ is both a target of antifungal drugs and enabler of immune evasion. It also contributes to a majority of the functional benefits we obtained by the consumption of mushroom and mushroom based products. It is constantly changing in response to stimuli and is key to the survival of a fungus. In this blog we will get an idea of the composition of the cell wall.

 

What is the cell wall

 

The cell wall of a fungus can be distinguished into two layers: an inner rigid layer and an outer fluid layer. The inner layer forms the structural component of the cell wall. It determines the shape and size of the fungal cell and it prevents the cell from bursting by taking in too much water.

 

The cell wall is located outside the cell membrane. Ninety percent of the cell wall is composed of polysaccharides. Polysaccharides are long chains of carbohydrate molecules known as monosaccharides bonded together to form a polymer. The most common monosaccharide molecule found in fungal polysaccharides is glucose. Galactose and mannose are also found in lesser proportions. Individual monosaccharides are connected to each other through glycosidic linkages. Polysaccharides are named based on their monosaccharide composition and the nature of the glycosidic bonds between the monosaccharides. 

 

The remaining ten percent of the cell wall may be made up of proteins, lipids and other minor biomolecules. The three major polysaccharide components of the fungal cell wall are: mannoproteins, beta glucans and chitin. Let’s have a look at these three in a bit more detail.

Cell Wall Components

 

Fig: Cartoon representation of a Candida albicans (yeast) cell wall (Source)

 

Layer 1: Mannoproteins

Mannoproteins form the outermost layer of the cell wall. This layer consists of polysaccharide chains composed mainly of mannose. A variety of proteins can be found attached to these mannan chains and therefore they are called mannoproteins. This layer is more fluid and porous than the other layers. As the outermost layer, it serves the important function of interacting with the surroundings of the fungal cell. The composition of this layer is highly variable across different fungal species and therefore the least is known about this layer.

Layer 2: Beta Glucans

Fig: Representative structure of fungal beta glucans consisting of long 𝛃 (1-3) chains with short branches of 𝛃 (1-6) linked D-Glycopyranosyl units (Source)

The next layer of the cell wall is made up of the famous beta glucans. These form the core structure of the cell wall and form the link between the inner rigid layer and the outer flexible layer. They are composed of long chains of glucose molecules linked to each other via 𝛃 (1→3) glycosidic bonds. These long chains contain short branches also composed of glucose which are linked through 𝛃 (1→6) glycosidic bonds. This results in the formation of a mesh or net-like structure in which other components such as proteins can be embedded.

Layer 3: Chitin

Fig: Representative structure of a chitin molecule consisting of 𝛃 (1-4) linked N-acetyl-Glucosamine (Source)

 

The innermost layer of the cell wall is composed of chitin. This is the most rigid part of the cell wall. Chitin is the most abundant molecule in the cell wall. Chitin and beta glucans are bound together and form the structural part of the cell wall. The chitin molecules form short chains organised into structures known as fibrils. 

These are helical structures that wind around each other (much like a rope). The fibrils of chitin assemble to form tightly packed sheets.  Due to this packing it acts as the protective layer of the cell wall, shielding the cell membrane from the harsh outer environment. The beta glucans are found attached to these chitin sheets.

Chitin is the oldest component of the fungal cell wall, surviving through evolution to become the most abundant molecule in the cell wall. Many fungi develop thick chitin layers when the cells are exposed to stress. 

The ratios of the different cell wall components are highly variable based on the fungal species. This species to species variation is sometimes used in their identification. 

Functions of the cell wall

The cell wall performs many functions in the fungal cell. Its most obvious function is protection. It also acts as the main structural backbone of the fungal cell, determines the shape and size of the cell and helps some fungi evade immune responses.

By forming a multilayered barrier around the fungal cell, the cell wall helps the cell withstand stressful conditions. The cell walls respond to different stresses by altering their composition. For instance, research shows that Aspergillus niger cells can increase the chitin composition of their cell walls by 2.5 times when they are starved. This results in the formation of a thick protective layer that allows the fungus to survive till it encounters a new nutrient source.

As fungi often live in highly variable environments, the composition of molecules such as salts and minerals are constantly changing in their surroundings. The change in salt concentrations lead to the formation of diffusion gradients which result in changing water levels within the cell. In conditions of low salt, the fungal cell swells up due to increased water content. As the cell swells, the cell membrane pushes against the cell wall and exerts pressure on it. These internal pressures can reach as high as 10 MPa in certain fungi. This is 20 times the normal atmospheric pressure! Without the cell walls, the cells would burst.

Fungi which form mycelial threads have elongated cells attached end to end and form highways for the transport of nutrients and water from one end to another. This movement of nutrients is essential to the maintenance of soil ecology. 

The fungal cell wall is of immense importance to human health. As it is the interface between the fungus and the external world, it acts as a beacon to our immune system indicating an infection. Most of the major components of the fungal cell wall can be detected by proteins on human immune cells. Upon detection, the immune cells release signaling molecules that inform the immune system of a fungal invasion and trigger an immune response. 

To take advantage of this directed immune response, many pathogenic fungi have evolved mechanisms to avoid their detection by altering their cell wall chemistry. These chemical modifications prevent the detection of the fungal cells by our immune cells and allow the fungi to go unnoticed. Other fungi can secrete molecules that act as decoys and prevent the recognition of the fungal cell walls by masking the proteins of the immune system.

 

Fig: Transmission Electron Microscope images of cell walls from three different fungi showing the variability in cell wall structure (Source)

 

Synthesis of the cell wall

The formation of the fungal cell wall is a complicated process with multiple steps along the way. Most of the molecules that form the cell wall are assembled within the cell in by the activity of enzymes. These enzymes string together molecules one by one to form the chains that make up the polysaccharides of the cell wall. 

Both chitin and glucans are extruded through the plasma membrane of the fungal cell. The basic ingredients for the formation of these molecules are nucleotide diphosphates. In the case of chitin and beta glucans, uridine diphosphate-sugars (UDP) are the carriers that bring together the monosaccharides which form the polysaccharide molecules that are incorporated into the cell wall.

Chitin is synthesised by a family of enzymes known as chitin synthases. These enzymes act on UDP-N-acetylglucosamine. The type of chitin synthase and their relative proportions in the cell determine the structure of the chitin molecules that end up in the cell wall. Similarly, beta glucans are formed the the activity of enzymes belonging to the glucan synthase family. These enzymes string together UDP-glucose molecules.

These enzymes can be found coexisting with each other near the cell wall where they actively extrude these components. Once the polysaccharide molecules are extruded, local enzymes embedded in the cell wall chemically link them to form the complex, multi-layered structure that we observe. The constant change in the number and kinds of proteins in the cell wall affect their structure and help the fungi adapt to various environmental conditions.

Fig: Cartoon representation of fungal cell wall synthesis. Chitin and 𝛃 glucans are synthesised by chitin synthase and 𝛃-1,3-glucan synthase enzymes respectively. The enzymes are embedded in the plasma membrane and extrude polysaccharide molecules to form the fungal cell wall (Source)

 

Conclusion

Up until the 20th century, the cell wall was assumed to be a passive structural element of cells. However, recent research has highlighted the constantly changing and highly regulated nature of the cell wall. As this structure forms the interface between the external and internal worlds of the cell, it needs to constantly adapt and mediate the survival of the cell. These structures have evolved to be highly complex and can vary immensely between species. However their two core components, chitin and beta glucans, have stood the test of time and are found in all fungi. As such they are responsible for many of the functional benefits observed when we consume fungi. In the next blog we will take a more detailed look at beta glucans and how they help our immune system.

 

References

Jean-Paul Latgé. 2007 “The cell wall: a carbohydrate armour for the fungal cell” DOI: 10.1111/j.1365-2958.2007.05872.x

E.P. Feofilova. 2010 “The Fungal Cell Wall: Modern Concepts of Its Composition and Biological Function” Microbiology. DOI: 10.1134/S0026261710060019

K. Vega and M. Kalkum. 2012 “Chitin, Chitinase Responses, and Invasive Fungal Infections” International Journal of Microbiology. DOI: 10.1155/2012/920459

Neil A.R. Gow et. al. 2017 “The Fungal Cell Wall: Structure, Biosynthesis, and Function” Microbiology Spectrum. DOI: 10.1128/microbiolspec.FUNK-0035-2016

Ruiz-Herrera and Ortiz-Castellano. 2019 “Cell wall glucans of fungi. A review” The Cell Surface DOI: 10.1016/j.tcsw.2019.100022

De-Oliva Neto et. al. 2015 “Yeasts as Potential Source for Prebiotic β-Glucan: Role in Human Nutrition and Health” DOI: 10.5772/63647

In Part 1 of this 3 Part Series we discussed the ways in which scientific studies have shown Pleurotus tuber-regium to aid and help with cancer.

Part 2 will take a deep dive into one of the most prolific diseases of our current generation. 

Diabetes is a disorder that renders the body incapable of dealing with its own glucose load. While there are many ways in which a person can reach the point of being diabetic, one thing is common among them all – diabetes is not fun! Diabetes leads to impaired wound healing, improper weight maintenance, the need to supplement with medication on a daily basis, and an overall decreased quality of life. India is currently the diabetes capital of the world with over 70 million diabetics in the country as of 2019. An increase in packaged and processed foods along with sedentary lifestyles and carbohydrate-laden Indian diets have been heavy contributors to this rise. 

Part 2: Diabetes

Pleurotus tuber-regium for diabetes

Many laboratories around the world have been looking towards mushrooms as a potential tool to reduce the rates of diabetes occurrence.
Mushrooms contain a wide variety of bioactive molecules that can contribute towards a healthier physiology

In 2012 researchers from Taipei investigated the effects of Pleurotus tuber-regium polysaccharide extracts on rats that were made diabetic. The rats were injected with a drug called streptozotocin. This compound is particularly toxic to pancreatic beta cells which are responsible for the production and secretion of insulin in a normal body. The loss of insulin-producing cells pushed the mice toward diabetes. The mice were also fed a high-fat diet which further enhanced their diabetes. 

Polysaccharides were extracted from P. tuber-regium with hot water and precipitated with ethanol. The purified polysaccharides were administered to the diabetic rats every day for 8 weeks and The rats were monitored for weight gain and other common clinical signs of diabetes such as oral glucose tolerance, Hba1c levels, and serum insulin. To their surprise, the polysaccharide-treated rats gained less weight on high-fat diets when compared to untreated mice. Furthermore, the polysaccharide-treated rats also had higher insulin levels, lower Hba1c, and better glucose tolerance. The polysaccharide-treated rats it seemed were less diabetic.

Pleurotus tuber-regium versus fat

With some positive indications, the investigators delved deeper into the body weight mystery. They measured common health markers such as serum triglycerides and cholesterol levels. These circulating fats are bad for cardiovascular health when they stay abnormally high for many years together. Surprisingly the researchers found that the polysaccharide treatments also resulted in lower cholesterol and triglyceride levels indicating that the polysaccharides were possibly affecting fat distribution in the body as well. This could explain the lower weight gains observed in the polysaccharide-treated rats.

In an extension to the above study, the scientific team looked at how the liver was affected by the polysaccharide treatment. The liver is at the center of many metabolic pathways, including cholesterol and triglyceride metabolism. Since the polysaccharides were affecting the serum cholesterol and triglycerides, the liver was an obvious place to take a deeper look. They discovered that a protein named PPAR-⍺ was more prevalent in the livers of the polysaccharide-treated rats. PPAR-⍺ increases the expression of genes responsible for fat metabolism. The polysaccharides were able to stimulate the metabolism of fats in the liver thus resulting in lower triglyceride levels. 

Combo, that works!

The high fiber content in P. tuber-regium extracts and whole mushrooms should not be ignored when considering these effects. Soluble dietary fiber is known to reduce fat and cholesterol absorption in the intestine. The lower absorption of fats combined with the increased metabolic activity of the liver together could have reduced the metabolic burden on the diabetic rats. The extracts are also rich in flavonoids which have strong antioxidant properties. These antioxidants can reduce damage to cells and in particular may have aided in the survival of the pancreatic beta cells. 

So what does this mean?

So how is this information really relevant to us?

There is no evidence that states that the use of such extracts in diabetic patients will have similar effects. However consuming foods rich in antioxidants and fibers have been shown to aid in healthy aging. Diabetes in most cases is a result of metabolism going bad. When we are young and relatively active, our body is more capable of dealing with the stresses of daily life. As time progresses, the accumulating stress overcomes the natural defenses the body has and pushes it towards a disease state. By aiding the body’s fight against the disease state, health span increases even if lifespan does not. In fact, it has been shown that chronic high-fat diets lead to insulin resistance and eventually diabetes. Tackling the issue from the onset can help offset this pathway and may even prevent it. 

Low serum triglycerides and cholesterol are important indicators of good cardiovascular health. It is most often cholesterol and triglycerides that end up being deposited in the small arterioles and venules of our bodies. The deposits eventually block these capillaries and can lead to what is commonly known as heart attacks, thromboses, or strokes depending on where they occur. By reducing fat absorption, high-fiber diets help support cardiovascular health. By preventing the build-up of sludge, flavonoids keep our capillaries healthy. 

Biochemical analysis of P tuber regium fruiting bodies showed that they are rich in proteins, fibers, and carbohydrates and low in fats. Carbohydrates in this case do not equate to glucose since the carbohydrates here refer more to complex carbohydrates and will not contribute to the glucose load as much as starch prevalent in many other vegetables. These mushrooms also contain all of the essential amino acids making them a complete source of protein. Obese and diabetic rats fed with dried and powdered P. tuber-regium had similar serum lipid profiles to rats treated with the antidiabetic drug Glibenclamide. 

1. tuber-regium is a unique mushroom that has been used by traditional communities for hundreds of years to help treat various ailments. Are they truly medicinal, we can’t say for sure. They sure are delicious though!

Stay tuned for the final part of this series!

References

Ikewuchi, Catherine Chidinma et. al. 2017. “Restoration of plasma markers of liver and kidney functions/integrity in alloxan-induced diabetic rabbits by aqueous extract of Pleurotus tuberregium sclerotia”. Biomedicine and Pharmacotherapy.  DOI:10.1016/j.biopha.2017.09.075

Huang, Hui-Yu et. al. 2012. “Pleurotus tuber-regium Polysaccharides Attenuate Hyperglycemia and Oxidative Stress in Experimental Diabetic Rats”. Evidence-Based Complementary and Alternative Medicine. DOI:10.1155/2012/856381

Huang, Hui-Yu et. al. 2014 “Effect of Pleurotus tuber-regium Polysaccharides Supplementation on the Progression of Diabetes Complications in Obese-Diabetic Rats”. Chinese Journal of Physiology. DOI:10.4077/CJP.2014.BAC245

Onuekwuzu, Ifeanacho et. al. M 2019. “Anti-Diabetic Effect of a Flavonoid and Sitosterol – Rich Aqueous Extract of Pleurotus tuberregium Sclerotia in Alloxan-Induced Diabetic Rabbits”. Endocrine, Metabolic and Immune Disorders – Drug Targets. DOI:10.2174/1871530319666190206213843

Lin, Shaoling et. al. 2021. “Research on a Specialty Mushroom (Pleurotus tuber-regium) as a Functional Food: Chemical Composition and Biological Activities”. Journal of Agricultural and Food Chemistry. DOI:10.1021/acs.jafc.0c03502

Adeyi, Akindele Oluwatosin et. al. 2021. “Pleurotus tuber-regium inclusion in diet ameliorates dyslipidaemia in obese-type 2 diabetic rats”. Clinical Phytoscience. DOI:10.1186/s40816-021-00321-0

 Tyagi, Sandeep et. al.  2011. “The peroxisome proliferator-activated receptor: A family of nuclear receptors role in various diseases”. Journal of Advanced Pharmaceutical Technology and Research. DOI:10.4103/2231-4040.90879

Lattimer, James M. and Haub, Mark D. 2010. “Effects of Dietary Fiber and Its Components on Metabolic Health”. Nutrients. DOI:10.3390/nu2121266

When we were starting our journey, we were completely new to the mushroom space and hardly knew anything about cultivating them. We took up mushroom cultivation because it seemed like something that could meet our goals- sustainable, profitable and scalable. If you want to know more about us and why we do what we do, please check out our About us page.

Our journey into the Indian mushroom cultivation space was far from smooth and had a lot of ups and downs. The important thing is that we made it this far and have figured out a lot of interesting things on the way which would have saved us a lot of time, effort and money if we knew it earlier.

This blog post is our way of passing on some important bits and pieces of information that we have acquired in our journey so that beginners don’t have to go through all the trouble we did.

 

1.     Choose your mushroom well

Each mushroom comes with its own set of advantages and disadvantages, some are easy to grow and grow really fast, others can fetch you a lot more money but they might be quite challenging and expensive to cultivate. You have to ask yourself a few questions which will help you find the mushrooms best suited to your requirements. Here are some questions that you can think about: 

• How much time and money am I willing to invest in this business? 
• How long can I wait before each harvest? 
• Which mushrooms are best suited for the climate around me? 
• Do I want to grow mushrooms seasonally or throughout the year? 
• Can I find the raw materials required to grow the mushrooms around me in an economical way?  

Mushrooms are not just what you see in the supermarket, they are also ingredients in various different industries such as food and beverage industry, nutraceuticals and functional foods, personal care, retail etc and are consumed in different forms – whole dry mushrooms, dry mushroom powder, fresh mushrooms, mushroom extract etc. When choosing your mushroom, you also need an understanding of where all it can be used and in what all forms.

Most trainers and courses will recommend Oyster mushrooms as a good mushroom to start with. They are not wrong but they aren’t completely right either. Yes, Oyster mushrooms are really easy to grow and they are quite forgiving of our mistakes. If you dig deeper, you will find that they have a really short shelf-life of 2-3 days from harvest. To make matters worse you will also realize that there is hardly any demand for them in the Hotels/Restaurants/Café sector because of their unpopularity among Indians. All the above factors make oyster mushrooms a not-so-good candidate for large-scale farms. You might be tempted to grow Button mushrooms because the demand for them is high but you cannot cultivate them without a climate-controlled setup (unless your local weather conditions are suitable) since they need temperatures between 16-19 degrees Celsius for it to fruit. So, please consider all angles before you choose which mushrooms to grow. Don’t just follow trends, take time to understand what has demand in your area and what can be grown easily.

2.     Understand the market

Once you have chosen which mushroom to cultivate, you have to study the local market for the same in-depth. You will have to find out before-hand which are the industries and channels that are currently using your mushroom and at what volumes and at what price. Try and talk to others in the same business if possible, to understand challenges that they might have faced. Make sure that you factor in things like ease of transportation and cost of packaging while you choose which channels to focus on. Understanding the market also means understanding the pain-points of the existing market so that you are better equipped at dealing with them. This step is very critical to ensure you succeed because without understanding the market you will not know how to position yourself or how to market your finished product.

3.     Develop your own market

After you have done an in-depth study of the market, you have all your facts and figures ready. Some questions to ponder at this stage are: 

• Which segments of the market can you realistically satisfy?
• What can you do to make your product stand out from the local competition?
• Some retailers require you to give them a fixed quantity on a daily basis, can your production meet those demands? 
• What resources do you need to satisfy the capacity you have settled on? 

Remember, you can always start small and scale up. For example: to get a feel of the fresh mushroom market start by selling to close friends and family or to your neighbors, to create your own loyal client base. You could even drop off samples at restaurants nearby and ask the chefs to give your mushrooms a try. Figure out what matters most to them (The freshness? Value for money? Packaging? Aesthetics?) and in the process learn how to best satisfy your customer. The easiest strategy would be to work with a few customers in such a way that you have forward orders for your harvest. You are ensuring that you have a ready market for your produce so that you can put all your energy and attention into cultivating high quality mushrooms in a way that your customers love them.

4.     Get the right training

This step is extremely crucial and the step which we here at Nuvedo had a hard time with. When we were starting out, we could hardly find any courses (both online and offline) which seemed legitimate. The courses were either too basic and lacked scientific explanation behind the processes involved or promised far too much to seem realistic – like lifetime support on cultivation and timely updates on technical advancements in cultivation for a fee of INR 750? I don’t think so! 

In our experience, we found that a lot of trainers were ex-mushroom cultivators themselves but turned away from cultivation and towards training because it was more lucrative. I don’t think that this is a good sign. If you’re getting trained make sure that it is under someone who either has a successful mushroom cultivation up and running or from a reputed consultant with a proven track record. We here at Nuvedo offer multiple avenues for different experience levels and requirements- starting from our DIY Mushroom growing kit for beginners to advance hands-on courses for specific mushrooms. Check out our Workshops section to stay up to date with our latest in-person workshops..

5.     Have a trusted vendor for spawn and raw materials

Once you have had some basic training and experience growing your first batch of mushrooms, you need to figure out how to get quality inputs for cultivation. The most critical input in ensuring you get a profitable yield is having good and reliable spawn. Without good spawn, you are bound to fail. You have two options: either 1) make your own spawn, which is time consuming and involves considerable effort or 2) buy it from a vendor, which might be a bit risky. When looking for vendors, make sure you find vendors who give you at least generation 2 spawn and have a hygienic and standardized setup with documented results. In India, getting high quality spawn can be a challenge because of lack of regulations or standards in the industry. If you want to ensure that what you’re paying for is of the quality that they promise, you can go through our in-depth blog on spawn. We here at Nuvedo have our own super spawn- NuvoSpawn, which is manufactured in our lab using the latest technology and best quality ingredients. We have documented the conditions in which our spawn performs best, so that you can get best yields each and every time. To know more about what spawn is and how it is used please visit our Spawn FAQ.

Apart from spawn, ensure that you have a steady source of substrate material that is available locally and at a cost that makes sense for your profitability goals. Different substrates can have varying effects on yield and quality of the mushrooms that you grow. If you want to know more about the effect that different substrates and techniques can have on your yield and quality, do check out our DIY Mushroom Growing Kit. As part of the kit, we provide an information pamphlet with various different substrate recipes along with a table to track your progress. The pamphlet contains basic definitions and even some formulas to calculate biological efficiency, hydration etc. 

6.     Prepare yourself for failure

Making one grow bag of Oyster mushrooms during training doesn’t prepare you well enough for the challenges that you will face while handling a bigger operation. Most people fail in the beginning when they try cultivating mushrooms at a commercial scale because there are too many variables involved and it is extremely hard to standardize the whole process. So, make sure that you are mentally prepared to accept failure. Your strategy should be- fail small and fail fast, so that you learn from your mistakes quickly and they don’t cost you so much money. You have to ensure that you document every single step so that you have evidence of what worked and what did not. This will allow you to finetune your entire process and develop standard operating procedures for each step. Standardizing your process and steps involved is critical to ensure that you can reproduce your results every time.

7.     Start Small and scale up

Your trainers or consultants might tempt you to go for a 100 Ton setup and you might be tempted to do so after your successful oyster grow but always start small. Start at a capacity where you are confident that you have a ready market for whatever it is that you produce. Once you have mastered the art of cultivating at a small or intermediate capacity then you can confidently invest money in the right places to increase your capacity and scale up production. Remember, selling mushrooms can be harder than growing them, so ensure that you have a ready market before you decide to scale up production. Starting small will allow you to make changes to your layout or process flow without incurring large losses. 

8.     Build a larger ecosystem of cultivators in your area

Like any other business, mushroom cultivation can fall prey to a lot of issues which can affect your turnover. Drastic changes in weather, contaminated spawn, equipment failure, labor shortage etc. can negatively impact your business. This is why it is important for you to ensure that you have a network of mushroom cultivators in your locality who can help you in case of emergencies like equipment failure or loss of cultures due to contamination etc. We at Nuvedo take pride in saying that we work closely with all our community members in ensuring that they succeed. Nuvedo gives its network of cultivators access to documented cultivation techniques, new advancements in cultivation technologies and also a list of our trusted vendors across the mushroom cultivation ecosystem. Nuvedo also has a group of highly trained and experienced professionals who help our customers troubleshoot and get the best possible output from their cultivation unit. We cannot thank our community members enough for all the support they’ve provided us on our journey so far. 

9.     Think about other streams of revenue

Apart from just cultivating and selling fresh mushrooms it helps to have other streams of indirect revenue coming in. For example, dehydrating and maintaining an inventory of dried mushrooms, making value added products from your mushroom such as pickles, soup powders, cookies etc. These additional sources of income ensure that you can protect yourself from market disruptions and other influences beyond your control. In the hypothetical case that the price or demand for fresh mushrooms drops in your locality, you now have the option of drying them and using them in your value-added products. With India still reeling in the aftermath of the pandemic, it is critical now more than ever to diversify your business into multiple streams of revenue so that you can keep your business safe from external challenges.

10.   Keep learning and share your knowledge

Mushroom cultivation is a fairly new space and there are lots of technological advancements being discovered on a daily basis. It is important to keep updating our knowledge on the latest developments in the field of fungiculture so that we can continuously improve the quality and output of our cultivation unit. It is equally important to share whatever knowledge we have with others in the mushroom ecosystem so that the whole community can develop and better serve the market. In today’s day and age the most successful companies keep much of their information open source as they know the importance that sharing the right knowledge can have on the larger business ecosystem. Investing time and resources in keeping yourself up to date and in innovation has a very large payoff in the long run. We here at Nuvedo, live by the philosophy “A thousand candles can be lit from the flame of one candle, and the life of the candle will not be shortened” . So go on and spread the spores of knowledge far and wide so that at least some of them can fruit when the conditions are right. 

 

Pleurotus tuber regium. The King Tuber Oyster Mushroom. This warm-weather mushroom has long been revered for its medicinal properties in parts of Western Africa, China and North East India. As the only sclerotium-forming member of the Pleurotus genus, it is unique in its ability to store nutrients for a rainy day. Here is a 3 part series taking a look at 3 diseases that this wonderful mushroom can protect you from.

 

In Part 1, we will refrain from fixating on the evolutionary wonders of the sclerotia but instead, look to them as sources of medicinal compounds. In particular, we will investigate some existing evidence relating the sclerotial extracts to antitumor or anticancer properties.

Part 1: Cancer

Beta-glucans as active molecules

Our journey begins at the Chinese University of Hong Kong where Peter Cheung and colleagues made use of hot alkaline water to extract polysaccharides from the sclerotia of P. tuber-regium. Polysaccharides are long chains of sugar molecules such as glucose that are connected to each other through chemical bonds. These polysaccharides are important structural components of every fungal cell. In their study, the researchers chose to focus primarily on the long and branched polysaccharide molecules known as beta-glucans.

The researchers used two commonly used cancer cell lines to test the effects of their beta-glucan extracts. HL-60 cells are derived from a patient suffering from acute myeloid leukemia (AML), a form of blood and bone marrow cancer that is also the most common form of such cancer in adults. When they treated the cells with their beta-glucan extracts, they noticed that the outer membranes of the cells became more porous. A blue dye called Trypan blue which is normally kept out of the cancer cells by the cell membrane was able to enter the cells and stain them blue. This indicated that the extracts were able to disrupt the integrity of the cell membrane of the leukemia cells. 

To verify whether the extracts could work on other forms of cancer, the researchers used another cancer cell line called HepG2 cells. HepG2 cells are derived from hepatocellular carcinoma (a form of liver cancer) and are commonly used to screen drugs for toxicity and study liver cancer. When these cells were treated with the P. tuber regium beta glucan extracts their metabolic activity decreased. A decrease in metabolic activity indicates stressed, dying, or non-functional cells. This indicated that the P. tuber regium beta-glucan extracts had a negative effect on the HepG2 cells as well.

At this point, an obvious question that the researchers had to answer was whether the adverse effects seen by the extracts were only on cancer cells. The extracts could have similarly deleterious effects on normal and healthy cells too, which would make them hazardous for consumption. To check if this was true, they tested the extracts on kidney cells obtained from an African green monkey (Vero cells) and found that the effects that they had observed on the cancer cells could not be seen here. This was an indication that the extracts were more harmful to cancer cells than to normal cells.

The importance of solubility

Now that they had some evidence that the beta-glucan extracts from P. tuber regium had some anti-cancer effects, the scientists wanted to improve the solubility of the extracts to make them more easily consumed. To do this, they modified the beta-glucan molecules by adding water-loving or hydrophilic chemical groups to them through a process known as carboxymethylation. This made the molecules easily soluble in water and therefore more bioavailable. They then added different doses of this modified beta-glucans to a human breast cancer cell line (MCF 7 cells). They observed a dose-dependent decrease in the metabolic activity of these cells. By monitoring the change in the number of DNA molecules in the treated and untreated cells they showed that the treated cells were multiplying much slower than the untreated ones. Further investigation showed that the treated cells were more prone to death as well. This highlighted the anti-cancer abilities of these extracts against breast cancer cells.

Size matters

The evidence provided by the studies so far sheds some light on the ability of P tuber regium sclerotial extracts to prevent or reduce the growth of cancer cells. However, a cell in a dish in the lab does not replicate the dynamic environment within the body. Another group of scientists from China’s Wuhan University decided to dissect this very aspect. They chose to work with Sarcoma 180 cells, a highly malignant mouse cancer cell line widely used in the field of cancer biology. They extracted water-soluble compounds from the sclerotia of P. tuber regium and further separated the molecules based on their sizes and biochemical properties. Once again the beta-glucans proved to be the molecules of interest. Moreover, the size of the beta-glucans had an impact on their effectiveness. Longer beta-glucan chains were more active when compared to the shorter ones. When it came to beta-glucans and their anti-cancer activities, size did matter it seemed.

In vivo effects

To replicate a more likely pre-clinical scenario, the Sarcoma 180 cells were transplanted under the skin of mice and allowed to form an active tumour. These mice were then injected with either 5-fluorouracil (an anticancer drug) or the beta-glucan extracts from P. tuber regium every day for eight days. On the ninth day, the tumours were dissected and weighed. Two of the extracts tested outperformed 5-fluorouracil and showed a greater reduction in tumour weight. This indicated that the extracts were not only able to prevent cancer cell growth in a dish, but also do so when injected into live animals. 

 

Taking a look at the evidence so far points to the ability of the polysaccharide extracts from Pleurotus tuber regium to inhibit the growth of cancer or tumor cells. However, it is important to keep in mind that all of these studies have been performed under highly controlled laboratory settings using well-established, immortal cell lines and do not necessarily recapitulate the true behavior of the disease. The in vivo mouse study by Zhang et. al. does indicate that the injected molecules are able to find the tumor and affect its growth negatively. However, the mode of injection, the location of the tumor, and the dosing protocol did not perfectly reflect an actual clinical scenario in a human patient. No successful clinical trials have been conducted to date that conclusively shows the efficacy of such extracts in the treatment of cancers or tumors. Keeping this in mind, we must evaluate the evidence that continues to grow day by day. Can these mushrooms help in the treatment of cancer?

Only time can tell. But they sure are delicious!

Read Part 2 on Diabetes of the blog King Tuber Oyster Mushroom: 3 Diseases it can protect you from: (PART 2/3)

References

Cheung, Peter C. 2001. “Chemical structure and chain conformation of the water-insoluble glucan isolated from Pleurotus tuber-regium.” Biopolymers.

Zhang, L. 2001. “Evaluation of mushroom dietary fiber (nonstarch polysaccharides) from sclerotia of Pleurotus tuber-regium (Fries) singer as a potential antitumor agent.” J Agric Food Chem.

Zhang, Lina. 2008. “Characterization of polysaccharide-protein complexes by size-exclusion chromatography combined with three detectors.” Carbohydrates Research. 

Zhang, Lina. 2009. “Chemical modification and antitumor activities of two polysaccharide-protein complexes from Pleurotus tuber-regium.” Int J Bio Macromol.

Zhang, Mei. 2003. “Molecular mass and chain conformation of carboxymethylated derivatives of beta-glucan from sclerotia of Pleurotus tuber-regium.” Biopolymers.

Zhang, Mei. 2004. “Carboxymethylated β-glucans from mushroom sclerotium of Pleurotus tuber-regium as novel water-soluble anti-tumor agent.” Carbohydrate Polymers.

 

Before you start exploring this blog about mushroom spawn, It will be really helpful if you are familiar with the basics of what mushrooms are and how they are cultivated. If you’re new to mushroom cultivation, please check out these blogs to know more about how mushrooms grow and the jargon used in mushroom cultivation:

• Lifecycle of a Mushroom
• Glossary | All things Fungi

Mushroom spawn is very critical if not the most important input in the mushroom cultivation process. We try to clarify the most commonly asked questions about mushroom spawn in this blog, in order to equip you with the right knowledge. Here is a look at the different questions that we will be addressing:

• What is mushroom spawn?
• Why can’t we cultivate from spores?
• How is spawn made?
• What is the difference between grain spawn and sawdust spawn?
• What are the qualities of good spawn?
• How do we store spawn properly?
• How do we know if the spawn we have is good?

What is mushroom spawn?

Mushroom spawn is basically mycelium, the living fungal culture, grown onto a substrate. It is the most critical input in mushroom farming and is used by mushroom growers similar to how farmers and gardeners use seeds. Mushroom spawn, unlike seeds, is grown from selected genetics and cloned so that it is possible to consistently produce a particular cultivar (cultivated variety) of mushroom which exhibits desired traits. This is similar to how people grow fruit trees via grafting as opposed to planting their seeds. Grafting is done to make sure that the fruit tree consistently produces delicious fruits because of a particular set of genetics that are chosen. Spores (and seeds for that matter!) are a genetic lucky dip dependent on two individual sets of genetic material, whereas spawn is a single, unique genetic culture that can be indefinitely propagated from the same ‘mother’ culture. Our ‘mother’ cultures are kept in the laboratory on agar petri dishes and maintained at the optimal temperature.

 

Spawn bags being prepped under sterile conditions in the lab

 

 

Why can’t we cultivate mushrooms from spores?

In the wild, mushrooms produce tens of thousands of spores (some even billions!) and get scattered across the forest by wind, rain, insects and other agents. They are on a quest to find the most suitable growing conditions but sadly the vast majority of spores will never grow into a mushroom fruit-body. As a cultivator this is not a risk that you can take, you want to ensure that you get consistent, reliable and repeatable results every time.

Another factor to consider is that spores are not sterile and growing using spores directly might lead to an increase in contamination rates which will affect your productivity drastically.

At Nuvedo we select productive strains of edible and medicinal fungi to make spawn which have been proven to give consistent results in the Indian setting, so that our cultivators can maximize their success.

How is spawn made?

All spawn start out their journey on a petri-plate as a pure fungal culture of mycelium. Once the mycelium has fully colonized the surface of the agar, a tiny piece of the mycelium is transferred to boiled grain. This mycelium is then allow to grow on the surface of the boiled grain for 3-4 weeks until it colonizes all of the grain. This myceliated grain is what is called grain spawn.

 

Step 1

 

Step 2

Apart from different grains such as wheat, jowar (sorghum), millet, rice, etc. some spawn producers even use sawdust and wooden dowels as a substrate for making spawn. The substrate used to make spawn serves three functions-

• Act as a surface for the mycelium to grow and spread on
• Provide the mycelium with macro and micronutrients so that it stays alive and healthy till it is inoculated on the final substrate material
• Act as multiple points for the mycelium to grow from and colonize the final substrate material at a faster rate from different parts of the substrate

We produce all of our spawn at our state-of-the-art facility in Bengaluru. NuvoSpawn is produced on sorghum grain in sterile lab conditions. We start by taking mushroom cultures from our culture bank and then growing them out on sterilized grain in a controlled environment, using our own standardized process and media, to ensure that our customers get the best quality time and again!

To ensure consistent results we grow our own mushrooms at regular intervals and keep track of the cultivation parameters of each and every strain. We do not sell spawn of any mushroom that we ourselves have not grown. If you’re buying spawn for the first time, make it a point to ensure that your spawn vendor grows their own mushrooms to ensure the variety is still performing consistently.

 

Nonabsorbent cotton plugs being inserted into the neck of the spawn bag inside a Laminar Air Flow

 

Inoculation of sterilized sorghum with a myceliated agar wedge

 

 

Final packing of spawn bag after inoculation under aseptic conditions

 

What is the difference between sawdust spawn and grain spawn?

Grain contains a lot more nutrition as compared to sawdust. This can lead to contamination or increased chances of attack by pests if used to make outdoor beds or logs. When the cultivator wants to grow in an outdoor environment where there could be pests or where the chances of contamination are higher, sawdust spawn is a much better option. Using sawdust spawn for conventional cultivation can lead to lower yields and slower colonization as compared to grain spawn.

What are the qualities of good spawn?

The most critical parameters for good spawn from a cultivator’s point of view is:

• It should be free from contamination

  1. The spawn has to be made under aseptic conditions preferably under a Laminar Air Flow to ensure the best results
  2. All materials used must be of the highest quality. Using low-quality or broken grain can lead to increased chances of contamination post inoculation.
  3. Grain used has to be boiled to the right consistency to ensure that it doesn’t break or get squished post inoculation. This is really important in ensuring low contamination rates.
  4. Grains/sawdust needs to be sterilized in an autoclave at 121 degrees Celsius and 15 PSI pressure to make sure that no microbial life persists

• It should be fast colonizing

  1. Genetics that are old or not maintained well undergo “senescence” or deterioration, leading to slow growth and poor yields

• It should give good yields

  1. Strains are one of the most critical factors which determine yield so spawn manufacturers should use commercial cultures which give high yields
  2. If cultures are not maintained well, the fungus can lose its virility over time leading to poor yields

• It should be free from toxic chemicals, antibiotics, and pesticides

  1. Some spawn manufacturers have been seen using hazardous chemicals such as formaldehyde to fumigate their labs and some even add antibiotics such as gentamycin to their media to keep it free from microbial contamination
  2. Over time, exposure to these chemicals can cause detrimental health issues to the cultivator who handles these materials
  3. Fungi can bioaccumulate complex molecules and the resulting mushrooms may contain trace amounts of these chemicals which will eventually affect the health and wellbeing of the consumer.

• It should give consistent results every time

  1. Some genetics are prone to mutation more than others and this can lead to variation in cultivation parameters such as speed of colonization, physical characteristics of the mushroom itself, and even yields.

 

Qualities of Good Spawn

We take pride in saying that NuvoSpawn is not just another bag of spawn. It is a technically superior product guaranteed to maximize your success by giving you consistent results time and again. We document the optimal growing conditions of our cultures to ensure that our customers can make the best use of our product.

NuvoSpawn:

• Is enriched with first-quality grain which ensures vigorous colonization and healthy growth.
• Is completely dry, pure fungus without wet patches to eliminate chances of bacterial contamination.
• Has been proven to give higher yields due to greater bio-efficiency because of our genetics and unique media.
• Is manufactured in a sterile environment which leads to a healthier growth of fungus.
• Uses disinfected nonabsorbent cotton to reduce chances of contamination.

 

How do we store spawn properly?

Your mushroom spawn is alive!! Yes, it is a living, breathing organism. In order to keep it healthy, happy, and strong we need to make sure that it is stored properly. A question we keep hearing is “how long can I store my spawn?” How long you can store your spawn depends on 3 things mainly:

• Cultivated variety or cultivar
• Storage Temperature
• Storage Conditions

 

Factors Affecting Spawn Storage

 

Let’s take a look at the factors one at a time:

• Cultivated variety:

It has been observed that varieties in which the mycelia grow slowly tend to have the longest shelf-life. To put it simply, the slower the growth of the variety the longer you can store it.

There are some basic signs to look for to understand if your mycelia are undergoing senescence or biological aging. The following are signs of the aging process of mycelia, in their order of appearance:

• The mycelia become more compacted
• The appearance of hard-looking crusts or lumps
• Formation of foul-smelling, colored liquid
• Self-digestion or autolysis of mycelium and degradation of mushroom spawn

 

4 Stages of Spawn Ageing

 

The mycelium is perfectly healthy and usable in stages 1 & 2 through the spawn might not feel as crumbly as it does when it is fresh. Self-digestion or autolysis starts happening at the end of stage 3, hence it is strongly recommended that you use your mushroom spawn before it happens. The mycelium has reached the end of its life in stage 4 and therefore the spawn should be discarded at this stage.

 

• Storage Temperature:

The ideal temperature for the storage of spawn is 0 to 4 degrees Celsius. At this temperature, spawn can be stored for anywhere from 2 months to 4 months. However, there are a few exceptions to this, for example, Pink Oyster mushroom spawn or Milky mushroom spawn tend to degrade if refrigerated since they are both tropical varieties.

 

• Storage Conditions:

If you have ordered boxes of NuvoSpawn, make sure that you place the boxes on shelves or stack them in an alternative manner like bricks, always making sure that you leave around 10 cm space between the boxes for airflow. If spawn for mushrooms like oysters has to be stored for extended periods, then take out each bag from the box and put them separately on the shelves inside the refrigeration unit. The refrigeration unit will have to be opened on a daily basis to ensure there is enough circulation of fresh air for spawn survival.

We strongly recommend you not to order or store your spawn months before the actual date of use. Whatever money you may save on shipping will be compensated by an increased yield and lower chances of contamination losses using fresh spawn.

At Nuvedo we do not keep any spawn that has aged more than 3 weeks to ensure that our customers get the best results, so it becomes really difficult to entertain last-minute requests as we are almost always booked out. The best-case scenario for us would be if you let us know 14-21 days before you need your spawn so that we can ensure the availability of fresh spawn. We will ship it out to you exactly in time for your inoculation!

 

How do we know if the spawn we have is good?

So, you’re waiting on your first batch of NuvoSpawn from Nuvedo or have a batch of mushroom spawn that you’ve been storing for a while now?
Without testing, you might have to inoculate your substrate and then wait a few weeks to come to the realization that the spawn you used was too old or not strong enough. To save yourself all that trouble you now want a quick and easy method to see if you can proceed with inoculation without worrying if the spawn you used was good enough. Well, you’ve come to the right place, all you need to do is follow the instructions mentioned below!

There are 2 ways of doing this, the hard way (which gives you more reliable results) or the easy way (which is cheaper and requires a lot less effort)

Let’s start with the easy way:

1. Take a sample of a few grams of spawn from each bag you wish to test.
2. Take a clean plastic container and put a small pile of wet paper (tissue paper, toilet paper, cardboard) on it.
3. Place the spawn on top of the paper.
4. Place the container in a clean, cool place away from direct sunlight.

The mycelium should be growing visibly on the paper in less than a week. This method is not foolproof and can give you false results so we would recommend you to follow the technique mentioned below.

The hard but reliable way:

1. Take a petri dish that has been prepared with PDA or MEA mixture.
2. Open the dish under sterile conditions, preferably under a laminar airflow, to avoid contamination. (Contamination can give your false results)
3. Using a sterile tool, such as a spoon sterilized under a naked flame, place a few kernels of mushroom spawn around the petri dish.
4. Under the laminar air flow, roll the kernels around under the petri dish. Close and label the petri dish.
5. Let the petri dish mature for 5 days to a week at a temperature beneficial for mycelium. We recommend around 20 Degrees for Oyster mushroom spawn or Shiitake mushroom spawn.

In a week you should observe mycelium growth from the place where the kernels were rolled over the agar medium and from the kernels themselves

The result: The strength of the spawn is indicated by the amount of mycelium growth present after a week. If the growth is fast and intense, your spawn is still very active. Old spawn also has a capacity to colonize the substrate like fresh spawn but the rate of growth will be much slower. So, the same applies to the kernels on your petri dish/paper towel. If you don’t see any growth in 5 days or so then that means that your spawn is too old and needs to be discarded. It is not that old spawn will not be active, it grows so slowly that contaminants get the upper hand and might take over your substrate. So, better safe than sorry.

Now that you have checked your spawn quality, you can confidently proceed with the next steps of mushroom cultivation if your test results came out well or order a fresh batch of NuvoSpawn in case your spawn is too old.

This brings us to the end of this blog, if you have any further questions or need any clarifications about spawn, feel free to reach out to us. We are more than happy to answer your queries.

Before I get into the mushroom side of things, let’s take a look at 3 not-so-good statistics about the current state of affairs in India –

1. 2022 was the hottest summer in India in the last 10 years with temperatures in parts reaching 49 degrees Celsius.
2. According to the latest National Family Health Survey (NFHS-5), India witnessed a 62% increase in the number of overweight children from 2016 – 2020. This alarming statistic is an indication that if neglected, we might face an obesity crisis.
3. Despite the blanket ban on plastics nationally, India still generates over 26,000 Tonnes of plastic every day with 60% of this ending up in landfills.

So, to put it simply- global warming is showing its true colors, our population is getting more obese by the day and our lands are being choked by plastic waste.

The million-dollar question on your mind now must be – what does all this have to do with mushrooms?!

Well, let’s find out!

As humans, we are drawn to mushrooms because of the unusual physical characteristics of their fruitbodies which magically appear after the first rains in fields and woodlands. Mycelium, which might not be visible, but is passively present within the ground below, waiting for favorable conditions.

Pleurotus tuber-regium has a similar story for us. This beautiful ochre colored mushroom was first stumbled upon by a member of our Cultivation Team at Nuvedo,while on a trip through the tropical jungles of Goa. He was quick to grab his camera and send us a couple of photos of this unique looking mushroom. Little did we know that this mushroom would soon be the reason for a lot of research, experiments, discussions and sleepless nights in our journey to work with the most healing mushrooms out there.

Ethnomycological Significance

Pleurotus tuber regium or King Tuber Oyster mushroom as it is commonly called is a relatively new mushroom for a lot of us in the mushroom space. They have been used by communities in West Africa and even in parts of North East India for many centuries as both an edible delight and also as folk medicine. These are not to be confused with the popular gourmet mushroom King Oyster (or Pleurotus eryngii) though they both share the characteristic feature of growing from the top surface of the substrate, rather than sideways like your conventional Oyster mushrooms do. Apart from this feature King Tuber and King Oyster mushrooms are two very different mushrooms. This mushroom derives its name from its unique ability to form truffle-like tubers underground, which are actually hard bundles of mycelium called sclerotia (which also act as food reserves for fungi). Apart from being a culinary delight, sclerotia contain a considerable amount of polysaccharides that are responsible for the multitude of medicinal properties that these mushrooms exhibit. If these facts haven’t blown your mind yet, let me tell you more!

 

Heat Tolerant Mushroom

King Tuber Oyster mushrooms are one among the most heat tolerant cultivable mushrooms out there, capable of withstanding temperatures up to 40 degrees Celsius! Now that’s one hot mushroom! With temperatures around the world increasing year after year, the effects of global warming cannot be dismissed. Keeping this in mind, these mushrooms have the potential to become a food source in places where other crops might find it hard to survive due to high temperatures.

These mushrooms have a lot of potential for commercial cultivation but a lot more research needs to be done to develop commercial strains which have superior yields before these mushrooms can become available to the masses. As of today, these mushrooms are a rare delicacy that is wild foraged from tropical forests in Africa, Asia, and Australasia.

We even have tribal communities in Tripura who use these wild-harvested mushrooms to cook up some amazing delicacies.

 

In the wild, King Tuber Oysters can be seen growing from rotting wood or from the soil. In the forests of Nigeria, these mushrooms can be seen growing around the African breadfruit tree. They are considered primary decomposers and can be cultivated on lignocellulosic waste similar to other gourmet and medicinal mushrooms. In their natural habitat, these mushrooms first form a thick bundle of mycelium underground, the sclerotia. Under favorable conditions, the fruiting bodies start to emerge from the sclerotia and appear above ground as beautiful light ochre mushrooms with funnel-shaped caps. These caps turn flat and proceed to turn wavy after the mushrooms reach full maturity. The sclerotia can be harvested and used to grow these mushrooms by simply planting it inside the soil, the same way you do with seeds!

Medicinal Uses 

Traditionally these mushrooms have been used in folk medicine in Ghana (4) for the treatment of a variety of health conditions including asthma, and high blood pressure and even to assist in weight gain for malnourished children. For all these purposes the mushroom/sclerotia is dried and powdered first and then used in soups or broths or even as an additive to flour used in cooking. One quick search for this mushroom on google will leave you with a multitude of research papers that show the therapeutic benefits of this special fungus.

King Tuber Oyster mushroom contain bioactive molecules which have been shown to help with-

• Lowering high blood pressure (2)
• Lowering high blood sugar (1)
• Lowering Cholesterol (1)
• Anti-Tumor/Cancer: (2,5)
• Anti-microbial properties (for Herpes Simplex) (2) (5)
• Anti-Obesity (2)
• Liver protection (2, 5)

Apart from medicinal benefits, King Tuber Oysters are also very high in potassium(3), anti-oxidants (2), and dietary fiber (equivalent to legumes or even seaweed)(5). It is an excellent prebiotic (2) and has also been explored as one of the few vegetarian sources of Glucosamine (5) which is used by patients suffering from various joint, bone, and inflammatory diseases such as arthritis.

Another really interesting property of this mushroom is its ability to break down polyethylene, which is a commonly used type of plastic! Don’t believe me, see the result of the study for yourself! As can be seen below, Pleurotus Tuber regium was able to decrease the weight of the polyethylene strips by a good 13.25% which is almost 50% higher than that compared to Pleurotus pulmonarius.

So we have with us a rare mushroom that grows in tropical jungles, is capable of withstanding scorching high temperatures, has the potential to treat a multitude of health conditions, and can eat plastic to top it off it also happens to be super tasty!

The obvious question most of you have right now would be where can I find these mushrooms? Or how do I cultivate these mushrooms at home? Don’t worry, we got you covered! Over the last year, our R&D team at Nuvedo HQ has been busy tinkering and finding a way to bring this powerhouse of a mushroom to your hands. After a lot of trial and error, we were successfully able to come up with the cultivation technology for this amazing mushroom which is now available for you to experience at home in the form of an easy-to-use grow kit!

You can grab one here: https://nuvedo.com/product/king-tuber-oyster-mushroom-growing-kit/

One last point that I want to touch upon before concluding is the culinary nature of King Tuber Oyster mushroom. Due to its high fiber content, the texture of the caps can be quite chewy compared to other mushrooms. Also, the stipe of the mushroom is hard and difficult to chew but brings in a unique texture, unlike any other variety. Throwing the stem away is not advised because there are a lot of polysaccharides and bioactive molecules present in it. You can chop them up or put them in the blender and make a paste out of it, which can later be added to soups or brother. The blended mushroom can be used in a similar fashion as a grated coconut!

Before you start exploring this blog, I am assuming that all of you are familiar with the basics of what mushrooms are and how they are cultivated. If you’re new to this, please check out these blogs to know more about mushroom cultivation and the jargon used:

• Lifecycle of a Mushroom
• Glossary | All things Fungi
• 3 tips for the Best Oyster Mushroom Growing Experience

Mushroom cultivation by its very nature is sustainable and has a positive impact on the environment. Just by cultivating mushrooms, we upcycle a lot of agricultural waste which would have otherwise been disposed of or burnt. Mushrooms also use only a fraction of water used by commercially cultivated crops.

What makes things better? The substrate leftover after growing mushrooms is a really good compost starter!
If you want to explore the positive environmental impact of mushroom cultivation then this blog is for you: Why India Needs More Mushroom Farmers: Environment

But all things said, the resting guilt most mushroom cultivators face, is the usage of single-use plastics. In this blog, we are going to look deeply at the use of plastics in the mushroom industry, viable alternatives, and advancements in the field of biopolymers that may be possible solutions.

To begin with – let’s get down to basics.

Why does one need to use plastics in mushroom cultivation in the first place?

Here are the 5 main uses for plastics in the mushroom cultivation process:

1. Prevent evaporation: Most of the commonly cultivated mushrooms are composed of ~80% water. This water is absorbed by the mushroom from the sterilized or pasteurized substrate which is hydrated to hold 55 – 70% water, as a percentage of the total weight of the substrate. The plastic acts as a physical barrier to ensure that the water present in the substrate doesn’t get lost due to evaporation.
2. Protect against contamination: Plastic is inorganic. It lacks the nutrition and hence doesn’t support the growth of any unwanted microorganisms that can negatively affect the growth of mycelium.
3. Keep pests out: Plastic acts as a physical barrier to stop pests from entering and eating up or contaminating your substrate.
4. Protect against physical damage: The plastic cover ensures that the loose substrate stays intact while it is being moved around and while the mycelium slowly spreads through the substrate making it one single mass.
5. Provide suitable microclimate: Certain mushrooms like Antler Reishi (shown in the picture below), King Oyster & Enoki need a specific microclimate (high in C02 for example) to grow a certain way, the plastic helps in maintaining certain cultivation parameters.

 

 

Are there ways to grow mushrooms without using plastic?

Now that we’ve established the uses of plastic, another important question we need to address before we proceed is, are there any established methods of cultivating mushrooms without the use of plastics? Yes! there are plastic-free ways to grow mushrooms, the most common methods being log/totem cultivation and bed cultivation. In log/totem cultivation, logs of suitable trees and the right dimensions are inoculated with mycelium. The mycelium then feeds on the log and colonizes it, giving out mushrooms when the weather is right. Many mushrooms such as Shiitake, Oyster, and Reishi can be grown outdoors using logs.

 

 

The major disadvantage with this method is that the cultivator has to wait a year or two before his first harvest and also the fact that harvests will be seasonal, making it hard to cultivate mushrooms throughout the year.

Finding the right wood, at the right time of the year and in the required dimension can be hard. Another challenge with logs is that they are heavy, moving and handling them can be very energy-intensive. Apart from logs, outdoor beds are also a great way to grow mushrooms without the use of plastics. In this method, the cultivator makes an outdoor bed using a pasteurized substrate that has been layered with spawn. One major drawback of this method is that the number of species that can be cultivated is very low, for example, Paddy Straw, Wine Caps, and certain species of oyster mushrooms.

Growing in beds can also lead to increased chances of contamination and attacks by pests. Both methods described above are still used in different parts of the world today and can be viable for the cultivator depending on his location and requirements but for a cultivator looking for consistent yields and year-round production, bag cultivation remains the most practical option.

Let’s dig a little deeper and understand what are the different types of plastic available in the market and which ones are suitable for growing mushrooms.

Based on what they are made of and how they degrade, plastics can be put in one of 4 categories:

• Bio-based and Biodegradable: These plastics are derived from natural sources and are biodegradable. Eg: PLA, PHA, PBS, Starch blends, etc
• Non-bio-based and Biodegradable: These plastics are derived from artificial sources and are biodegradable. Eg: PBAR, PCL, etc.
• Biobased and non-biodegradable: These plastics are derived from natural sources but are not biodegradable. Eg: Bio-based PET, PE, PTT, etc
• Non-bio-based and non-biodegradable: These plastics are derived from artificial sources and are not biodegradable. Nearly all conventional plastics fall into this category.

 

This categorization makes it very clear that just because something is made from a natural source doesn’t mean that it is automatically biodegradable and on the other hand just because something is made artificially it doesn’t necessarily have to be biodegradable. Another common mistake is thinking that compostable and biodegradable imply that if you simply throw away that piece of plastic, it will degrade by itself. This is incorrect, the words “compostable” and “biodegradable” imply that it can be composted or degraded under industrial conditions for composting or bio-degradation!

This brings us to our next question, what is the most suitable type of plastic available for mushroom cultivation and why?

Most cultivators prefer using Polypropylene number 5 or PP5 for short. PP5 is commonly used as packaging for foodstuffs and as containers for food as it is a very safe and stable polymer that doesn’t degrade easily. It is the safety coupled with the fact that it can withstand temperatures of 121 degrees and 15 PSI pressure with ease, (this temperature and pressure are encountered in an autoclave which is typically used to sterilize substrate bags) that makes polypropylene bags for mushroom cultivation most popular. Unlike PP5, biodegradable polymers such as PLA, PHA, etc. cannot withstand such high temperatures or pressure and have poor barrier properties. This makes these biodegradable mushroom bags unsuitable for mushroom cultivation commercially.

 

This being said, if you’re pasteurizing your substrate and can find a way for the substrate to retain moisture, you can try using biodegradable polymers available in the market for mushroom cultivation. Post use, they need to be sent to the right facility to be composted. There are scientific papers out there that have examined the ability of certain plastic eating mushrooms (some oyster mushroom species for example) to degrade bioplastics such as PLA. Keeping this in mind, please be sure that you are using a type of bioplastic which the mushroom mycelium cannot degrade! To know more about this please read this article.

A few materials that we often get asked about for mushroom cultivation are jute bags and clay/ceramic pots. Both of these aren’t viable alternatives to plastic. Jute bags are porous, so evaporation will not be controlled and since it is made from plant matter they can get contaminated very easily. As for earthen pots, they are full of micropores which can act as a surface to attract contaminants, and similar to jute, the porous nature of the material will result in a loss of moisture from the substrate. Apart from this, clay/ceramic pots are fragile and heavy, handling them without damage can become an issue if they are used at a commercial level.

Though plastics are bad for the environment, there is no denying that it is a really good material that has a lot of uses and is economically viable for mushroom cultivation. One viable alternative that a mushroom cultivator can try is growing mushrooms in containers. These reusable PP5 containers have a long life and can be used over multiple cycles without any need to be replaced. Mind you, this alternative may not be suitable for all varieties of mushrooms and there will be an additional step of cleaning and maintaining these buckets, which will need additional resources. For example: Growing King Oyster mushrooms in buckets will not work the same way as other oyster mushrooms because King Oysters grow vertically from the top as compared to other oyster mushrooms which grow from the sides. For that matter growing Shiitake mushrooms in buckets is not a good idea either since the blocks need to be removed from the buckets to initiate fruiting.

 

 

 

 

 

 

 

 

 

Here are some representations of the same: Enoki mushrooms and King Oyster mushrooms being cultivated in reusable mushroom growing containers:

While writing this I am hopeful about the future and I feel that it is just a matter of time before performance-based bio-materials become widely available and cost-effective enough to replace plastics altogether in the mushroom cultivation process. Mushroom cultivators around the world are rooting for the day when biodegradable mushroom bags for cultivation will become widely available. We might even have completely sustainable and biodegradable mushroom plastic or mycelium based plastic alternatives which can be used for mushroom cultivation in the future. Till then, let’s all be on the hunt for more sustainable materials and practices, and let’s all do our bit in growing the mycelium network!