Uses of the spent mushroom substrate

Nowadays, more and more people and companies are starting to grow diverse types of mushrooms all across the world. Statistics say that global production has increased to about 27 billion kg in 2012. Along with the steadily growing industry comes the increased volume of spent mushroom substrate. The production of mushrooms always results in significant residual material after harvest. The term “spent mushroom compost” (SMC) is mainly used by Europeans, while “spent mushroom substrate” (SMS) by Americans.  SMS/SMC is made from various agricultural materials like hay, gypsum, wheat-straw horse manure, sawdust, cocoa shells. Commonly, each cultivation cycle lasts for about 5 to 6 months and the spent substrate is usually disposed although it still has some available nutrients. Usually, before removing it from the mushroom house, the person in charge “pasteurizes” it with steam to kill any pathogens that might be found in the substrate. All in all, mostly all seeds, insects and agents that may cause mushroom disease are killed.

The abundance of spent substrate and the lack of waste management supervision has led the world in the search of new alternative ways of recycling and reusing.

Bioremediation

Bioremediation represents the use of living organisms such as bacteria and fungi in the removal and neutralization of different air, soil, water contaminants. The mushroom enzyme system has compounds like laccase, lignin peroxidase and manganese-dependent peroxidase which are responsible for catalyzing the metabolization of many structures like Polycyclic Aromatic Hydrocarbons and Phenols. SMS adsorbs the organic and inorganic pollutants and the microbes that inhabit the substrate have the ability to break down organic xenobiotic compounds. They also have strong pollutant catabolizing capabilities.

Crop Production

Mushrooms are generally cultivated using organic substrates and therefore scientists have searched different methods of using the spent substrate for growing different plants. Spent substrate of Agaricus bisporus has been used for asparagus, beetroot, onion, potato, radish and many more plants and has proved itself to have nutritional qualities.

In India, SMS has been used with success as “manure”. It’s converted to a liquid fertilizer and used on the soil. Also, the spent substrate of Pleurotus has been evaluated as a potential biofertilizer.

Biogas for heating or cooking

SMS is an ideal material for the production of marsh gas. It holds many nutrient substances that provide the basis for long-term propagation of bacteria that produces methane. Studies have showed that 3 to 5 kg of SMS can produce 6-10 m3 of biogas, enough for the daily use of a family.

Plant hormone

Scientists in Japan have developed a liquid plant hormone by using spent mushroom substrate. This was used on cucumbers, tomatoes, soybeans to promote their growth and increase the overall production.

Food for animals

Mushroom substrate holds different ingredients that are usually present in animal diets. They contain cereal straws and multiple grains that provide nutritional value. Lentinula edodes spent substrate is used in ruminants for digestion and Ganoderma balabacense to aid milk production.

Renewable energy

Agaricus bisporus, Pleurotus and Lentinula edodes are candidates to produce biogas, biofuel and alternative fuel. The substrate from mushrooms holds an optimum C/N ratio and therefore it improves the susceptibility to digestion of anaerobic fermenters. The low lignin content hand in hand with high nitrogen and ash content make the spent mushroom substrate more easily digested and therefore not working with it is less complicated.

Conclusion

Years of research have concluded that spent mushroom substrate is no longer a waste product that should be thrown away but a renewable source with numerous uses. Moreover, its utilization will not be limited to a few applications, SMS will be seen as a constant challenge for famers, scientists and entrepreneurs who will brainstorm more and more strategies for its roles.

A report by Malina Puia

 

References

Danny Lee Rinker “Spent Mushroom Substrate Uses”, 2017

Peter Oei et al., “The alternative uses of spent mushroom compost”, 2007

“Recycling of Spent Mushroom Substrate to use as Organic Manure” book

J. Maher, “The Use of Spent Mushroom Substrate (SMS) as anOrganic Manure and Plant Substrate Component”, 1994

Chia-Wey Phan, VikinesvarySabaratnam, “Potential uses of spent mushroom substrate and its associatedlignocellulosic enzymes”, 2012

https://extension.psu.edu/spent-mushroom-substrate

The nasty side of mushrooms

Mushroom farming is not only a source of nutritional rich food but also a provider of effective medicinal products. In the last decades, mushroom cultivation has become very popular among people all over the world. 31 billion tons was the number of the world’s total edible and medicinal mushroom registered in 2012. Different cultivating techniques have developed throughout the years and this has contributed to an increase in mushroom production. Cultivation has evolved from a relatively primitive method to a highly technological industry. The basic principles are the same for all mushrooms, but the practical approaches differ depending on the species. A person who decides to grow mushrooms for the purpose of consumption has to be aware that even though he or she does not skip any step of the grow process, toxic substances may still be present within the resulted frutibodies, and they should not be neglected. As one starts out in this field, the strategy should be identifying a strain that is compatible with the climate conditions in that specific area, is able to grow on the available substrates, has a quick production and requires a decent cost and infrastructure to sustain harvest consistently.

The presence of toxic substances like heavy metals in soil, air, water and organisms has always been of great concern and considered a threat to human health. They are cytotoxic, carcinogenic and mutagenic. Some of them are toxic even at trace levels. They tend to accumulate in tissues and organs and cause serious harm.

Interest is shown especially in the content of these substances found in edible mushrooms. Although cooking and preservation might decrease the levels it does not make them disappear. Fungi are indicators of heavy metal concentration in the environment. They reflect the level of contamination through different metabolic and morphological characteristics. Exposure to the heavy metal content results in physical, neurological and muscular disorders. There are several factors that contribute to the accumulation ability like species, heavy metal identity, the substrate’s pH, age of culture mycelia, etc. EFSA (European Food Safety Authority) has listed some safe levels for heavy metal ingestion known as TDI (tolerable daily intake). Nickel, a naturally occurring metal can be found in food and water as a result of industrial contamination. The TDI is 2.8 µg/kg of body weight. Mercury, a heavy metal of elevated risk is tolerable in 1.3 µg/kg of body weight. Cadmium, another very popular metal is labeled at 2.5 µg/kg of body weight TWI (tolerable weekly intake). Lead is an environmental contaminant whose occurrence is sustained by different human activities. Regulations have decided that the maximum levels present in mushroom should be of 0.30 mg/kg wet weight.

Researchers have found that the content of heavy metals in fruitbodie increases in polluted areas. What’s peculiar about this is that some species of mushroom are not affected by the pollution and the content of heavy metals found in them is significantly lower compared to others. Also, it was discovered that the cap held higher concentration than the stalk in most cases. A study performed on distinct species of mushrooms and conducted by several scientists found out that the highest cadmium concentration was signaled in Agaricus arvensis, 117 mg/kg. The highest nickel, Pleurotus ostreatus, 145 mg/kg. Concerning the concentration of mercury, an amount of 120 mg/kg was found in only one sporophore of Lycoperdon utriforme. Most species accumulate cadmium, lead and nickel.  There are some types of mushrooms that can present two metals in high concentrations: Agaricus bisporus, Lepista nuda (lead and nickel), Marcolepiota procera (lead and mercury), Agaricus sylvicola (cadmium and nickel).

Apart from heavy metals, fungi can also carry insecticides. Sugarcane bagasse is used in mushroom compost production. In order to prevent and combat pests, people use a substance called fipronil. It effectively controls insects but using it might lead to the formation of toxic metabolites. Exposure to insecticides is neurotoxic. Sun mushrooms have the tendency to accumulate fipronil from the compost if available and this poses threat to human consumption. Studies have revealed that the presence of fipronil in the compost did not lead to accumulation in fruit bodies. On the other hand, when added to the soil casing layer, the results showed bioaccumulation in the mushrooms. One interesting fact is that fipronil adsorption is higher in soils rich in organic matter.

Mushrooms are also vulnerable to radiocesium contamination occurring from a radioactive fallout. Boletus badius is commonly known to hold affinity for contamination with radioactive substances. After the Chernobyl nuclear incident, researchers have gathered samples of mushrooms from different parts of Poland and analyzed them for nuclear traces. The abundance of radiocesium in mushroom can be attributed to three factors: soil contamination, the specific uptake of various species and mushroom requirements. The radioactive compounds are adsorbed and deposited on the top organic layer of the soil. Some fungi with simplistic mycelia can accumulate these elements readily and in considerable amounts.

It is highly important to take into consideration every minor aspect when deciding to grow mushrooms. Growing them organically, even though it might imply more funds, tests and regulations, has more benefits on the long run but even with this on we won’t be absolutely sure that the mushrooms that we eat are clean.

A report by Malina Puia

 

References

www.efsa.europa.eu

“Organic Mushroom Farming and Mycoremediation: Simple to Advanced and Experimental Techniques for Indoor and Outdoor Cultivation” book by Tradd Cotter

  1. Chang, S. P. Wasser, “The Cultivation and Environmental Impact of Mushrooms”, 2017

Mogildea Daniela, “BIOACCUMULATION OF TOXIC HEAVY METALS IN MUSHROOMS – A REVIEW”, 2016

  1. A. Carvalho et al., “Bioaccumulation of insecticide in Agaricussubrufescens”, 2014
  2. Falandyz, et al., “Evaluation of the radioactive contamination in fungi genusBoletus in the region of Europe and Yunnan Province in China”, 2015
  3. Das, “Heavy metals biosorption by mushrooms”, 2005
  4. D. Raj, et al., “MUSHROOMS IN THE REMEDIATION OF HEAVY METALS FROM SOIL”
  5. Dulay, M. De Castro, “CADMIUM AND CHROMIUM TOLERANCE ANDMYCOREMEDIATION ABILITYOF TIGER SAWGILL MUSHROOM, Lentinustigrinus”, 2016

Liora Yuklea’s Fine Line highlights world’s food waste issue

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Image courtesy: fineline.my.co

Even though we might usually be too busy to contemplate about it, we all know it: the world today faces a lot of problems. Whether they are environmental, political or economic or whether they arise by mistake, ignorance or culture, we have to deal with them sooner or later. When enough resources are found, researches are undergone, which increases the chances for that problem to be eventually tackled. But even though you presented facts to a person which would make you more credible than if you only talked about it, it is not certain you would produce a change of perspective – humankind can be particularly stubborn when it comes to holding on to its interests and beliefs.

In these kind of situations, art comes in handy. For centuries, it has served as a tool for artists to spread a certain message, to reflect the society or to underline perhaps a not so evident thing to people. It can be an effective way of critique towards the establishment and could bring societal change or simply raise awareness. Obviously, as any tool, it can be used in malevolent ways, just like the dictatorial states have used it for propaganda. However, it can do what sometimes incomprehensible and dusty researches cannot do – convince the people.

This is what Liora Yuklea, a MFA student at the Design for Social Innovation program at the School of Visual Arts in New York, tried to do in her first semester. The result of the semester was a piece she entitled “A Fine Line”.

The project started out from the problem of food waste: a third of the food produced is thrown away. Imagine the world’s biggest stadium full to its entire capacity – that’s how much good quality untouched food goes to waste every single day in the USA. But simply throwing food away is not the only cause for this problem; a lot of food gets wasted because it doesn’t meet the “aesthetics standards” of size, color, weight and blemish level. In Britain, 40% of the fruit and vegetable crops don’t make it to the shops because they look too “ugly”. Our obsession with appearance creates ‘a fine line’ between two types of fruits or vegetables perfectly good to consume.

She created a dining set (a table with two chair and two plates) halved in two different realities – one part that is industrially produced and with a perfect finish and the other part, grown organically from a mix of mushroom mycelium and wood waste. She based the naturally grown part in the principle that the fungus can digest anything that is cellulose based. In the process of growing the material, the mycelium forms a spongy matrix of a material called chitin; it can take up any space and the growth continues as long as there is something for the mushroom to feed on and as long as there is moisture. If you dry it (at around 180 F) you stop the growing process.

This principle is the same Ecovative uses when manufacturing the packaging or the bricks. Liora started experimenting by inoculating petri dishes and jars of woodchips, gypsum and wheat germ with Reishi and Oyster mycelium. However, because of lack of experience a lot of the samples were contaminated and thus unusable. This lack of experience with growing organic furniture and also the pressure of time made her contact Ecovative itself to ship her their live mycelium and wood waste mix plus some already prepared mycofoam panels as back up. In the end, she managed to have the art piece created in time for the exhibition and deliver her ingenious metaphor.

You can find the whole development of her project and get inspired at fineline-my.co.

 

A report by Ioana Popescu

The eco-friendly burial suit uses carnivorous mushrooms

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Photo courtesy: beautifuldecay.com

Every day, we go on with our lives, with our more or less conscious routines, striving to survive or succeed in this world. And even though each member of the society is well-aware of the fact that death will eventually interfere with his or her life, we all are culturally used to dismiss the thought, doing everything in our capability to avoid thinking about death. You can see this in the mainstream obsession with looking young or the amount of money and time invested in this aim, but also in the tradition of embalming the deceased.

However, beyond cultural perception, it is high time we addressed the issue of dying as cemeteries are becoming too full for new ‘residents’. A consequence of this is the increase in cremations burials which hardly seems like a better alternative since it is extremely polluting – in the UK, 16% of the mercury pollution was caused by cremation, due to our dental fillings.

Indeed, there seems to be a new solution to this problem: green burials. This practice which started in the 1980’s as a backlash against crowded cemeteries in the UK translates into abandoning these unnatural practices such as formaldehyde-based embalming, metal caskets or concrete burial vaults. It’s basically how humans have been burying the dead for hundreds of years: letting the body be food for the soil.

Unfortunately, researches showed that even this way it’s not that environmentally good as one might hope for. Truth is that during our lifetime we store a lot of environmental toxins in our body. The most common might be bisphenol A (BPA) which is a material hardener and a synthetic estrogen that’s found in the lining of canned foods and some types of plastics. It mimics the hormones of our body and can cause neurological and reproductive problems. Studies found that BPA can be found in 93% of people aged 6 or older. But the Centers of Disease Control in the US argues that there are over 200 toxic chemicals in our body; these include tobacco residues, dry cleaning chemicals, pesticides, fungicides, flame-retardants, heavy metals, preservatives, etc. And after we die,all of them end up into the environment, through our bodies.

But artist Jae Rhim Lee came up with a solution, creating the Infinity Burial Project and what she refers to in her Ted talk as the “ninja pijamas”. With the idea in mind that the toxins in our body should not enter the ecosystem through decomposition, she created a mushroom burial suit. The costume is accompanied by a fungal strain that consumes dead human tissue, thus decontaminating the body, in a process of mycoremediation. This practice is already used in cleaning toxic sites and the lead researcher in this field is Paul Stamets. With organic toxins, fungi break down molecular bonds this way neuterlizing toxins or they break toxins down into simpler, less toxic chemicals. With heavy metals for example, the fungi bind the toxins through a process called chelation, making the chemicals harmless.

The mushrooms used are of two types: edible and mycorrhizal. The first ones are decomposers that can break down a variety of food producing enzymes while the latter type creates relationships with plant roots while also delivering nutrients to them.

By feeding dead skin, hair and nail to the mushrooms, Lee cultivated a fungal strain that would be able both to produce edible mushrooms and remediate toxins in our body. (However, the part with production of edible mushrooms is still being experimented with). In 2015, she joined with Michael Ma and founded together Coeio, a “green funeral start-up”. Their Infinity Burial Suit is a handcrafted garment, is biodegradable (of course) and was designed with the help of the zero waste designer Daniel Silverstein. As far as I know, one person already was buried in this suit and here is his story

To conclude, although the fact that even in death we can still pollute the Earth is thoroughly depressing, at least mushrooms combined with science and creativity can offer us eco-friendly funerals.

 

A report by Ioana Popescu

Textile innovations – bio-degradable mushroom dress

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Source & photo courtesy: neffa.nl

After all these reports I’ve been writing, I bet every reader has understood by now how wondrous fungi are. Moreover, as researches are exploring new possibilities, I think it’s very clear what an environmentally sustainable alternative the kingdom of fungi offers to already existing mundane things such as packaging, bricks or even paper.

So why would the fashion industry be the exception to this rule? Even though inspiration might come from past trends, designers are up to experimenting with different things in their humane quest to innovate the craft. Nowadays, probably the most inspiring tool is provided by technology which offers a new and limitless playground. Also, this technology is used for testing ideas for products with smaller impact on the environment, a subject that keeps on expanding as the concern regarding the future of our planet is growing.  Thus, it seems more than logical that the second most polluting industry on Earth should look for ecological alternatives.

One such initiative comes to life through Neffa company. Their name means in Dutch “wanting to do things just that bit differently” and their self-described mission is “to create textiles that act like living organisms and with which we live in symbiosis”. They aim to create materials using biotechnology that would resemble the skin and its dynamic. They are researching several organisms, for example algae and mycelium, but what I’ll be talking about is how the company uses mycelium to create a sort of textile, which they called mycoTex.

The soul of the company is Aniela Hoitink, a textile designer. In the beginning she was interested in creating a textile out of a living product, which will eventually end up in a wearable piece of clothing. That is how she began experimenting with mycelium that is the vegetative part of a fungus. What encouraged her in using the mycelium were the insulating and moisture-absorbing proprieties of it, which a lot of textiles miss. However, she was not alone in her endeavor: the University of Utrecht and Maurizio Montalti were helping with the technical part. What they tried to experiment with was: growing mycelium onto natural fibers, growing it with polymer spacer fabrics and growing it in a 3D star shaped petri-dish.

Some of the initial findings of these experiments were that mycelium does not grow on a tight knitted or woven fabric and that mycelium does not use the textile as a food source.

Eventually, Aniela developed the composite product named MycoTex and then decided to build a textile out of modules and shaped these circular pieces around a body form, thus creating the Neffa dress. This creation is groundbreaking because it can be built whilst being made, fitting the customer’s wishes, because it eliminates the possible leftovers made during the process and it can be composted when it’s no longer desired.

Another such invention came to life by the hands of Danish product designer Jonas Edward, who created a material called MYX, which is grown from mushroom spores and plant fibers. His idea combines natural plant fibers (agricultural waste) and oyster mycelium. During the production of the material which takes about two weeks, the mycelium spreads through the textile matt (hemp and linen fibers), behaving like a glue between the fibers. The mycelium who continues to collect energy from the plant material, breaks down the cellulose into sugar, in this way producing mushrooms ready to be eaten! (If the material is dried, there will be no “offsprings”). In the end, the creation of this material, from which the designer made a lamp with, produces no waste – something that the creator aimed for and which is also a great achievement in today’s manufacturing.

 

A report by Ioana Popescu