The commercial production system of Agaricus bisporus relies entirely on composting to generate a mushroom-specific substrate. This process is energy, time, and labor-intensive and releasing odor and high nutrients into the environment.
The goal of many researchers is, therefore, to find alternative processes and or substrates, which reduces on the one side the costs and on the other side the impact on the environment while maintaining high production.
Hence, in this video, I will talk first about the traditional way of growing button mushrooms, then second, about alternative methods, and third, if these new alternatives are being used and, if not, why not and how to make it work.
The standard process of preparing the substrate for the cultivation of the button mushroom is by composting it. The composting process itself is divided into three phases. In phase one, the substrate is wetted and turned over every day for 3 to 19 days. During this phase, the substrate will self-heat up to around 75°C / 167°F.
In the second phase, the substrate is then fill in tunnels and pasteurized at 57 to 60°C (135-140°F) for 6 to 8hr, and afterward maintained at 45 to 49°C (113-120°F) for 7 to 10 days. In this last step, the volatile ammonia, which is formed during the composting phase and suppresses the growth of the mushroom, will be removed from the substrate.
The total duration of these three steps can sum up to 40 days.
In the next step, the substrate gets inoculated and filled into beds and maintained at around 22°C/72°F. After the mycelium has fully colonized the substrate, it is covered with a casing layer (typically peat) and maintained at 18°C/64°F.
When it comes to alternative processes, I want to focus on non-composted substrates. The first one is the grain-based substrate. The author of the study uses commercial grain spawn and supplemented it with high protein delayed-release supplements. He called this process Satellite Mushroom Production Systems or short – SMPS.
After mixing the commercial grain spawn with the delayed-release supplements, the substrate is filled over perlite in trays and then cased with a peat-based casing layer. After the mycelium fully colonized the casing layer, the steps are similar to the traditional production system.
The author compared it to the Complete On-Site Mushroom Production System or short COMPS. Meaning all steps starting with the spawn production are done on-site. To produce the spawn, sterilized grains were supplemented with oilseeds and other ingredients. After the grain is fully colonized, the process is similar to the composted substrate.
The second non-composted substrate is grass-based. Here another author used Pangola grass, corncob, plus different supplements, which then were pasteurized at 65°C/149°F for 30 hours, turned and finished after 45 hours. Substrate and spawn were mixed and filled in bags and incubated at 24 to 26°C/75-79°F. After the bags were fully colonized, the bags were opened, and a casing layer was applied. The temperature was dropped down to 18°C/64°F and maintained for 3 weeks.
The third alternative is the sawdust-based substrate. Here again, from another study, the author used a 50:50 mixture of the non-composted substrate and spent mushroom compost. The non-composted substrate consists of a mixture of oak sawdust, millet, rye, peat and different supplements. Standard autoclaving was used to sterilize the substrate.
Comparing the process duration, yield, biological efficiency, and production cost per unit weight is necessary to evaluate these alternatives.
The compost-based substrate takes around 70 days from start to the first harvest. This is our reference point.
The SMPS takes roughly 47 days which is 33% faster than the reference. For the COMPS, the author mentioned around 75 days, which is slightly longer than the reference. The longer process time for the COMPS comes from the slower growth of mycelium on grain than on the composted substrate.
The grass-based substrate is with 46 days, similar to the SMPS.
Unfortunately, for the sawdust-based substrate, no data are available.
When it comes to the yield and biological efficiency, we get the following values. For the composted substrate 26+ kg/m² and a BE 178. These values will be used as our reference point.
For the SMPS we get for the 14.3 kg/m² and a BE 177. For the COMPS 21.3 kg/m² and a BE 273. Both yields are lower than the reference.
For the grass-based substrate 26,0 kg/m² or a BE 176 could be achieved. Which is almost similar to the reference.
And for the sawdust-based substrate 27.2 kg/m² with a BE of 144.
Overall, the alternative non-composted substrates can reach similar yields to the composted-substrate.
But yield and biological efficiency is only one side of the same coin. The retail price is around $4/kg mushroom. The sales price to retailers 50% lower (or more).
The cost for the compost-based substrate is around 75ct/kg mushrooms. Which means this process can be profitable. For the SMPS, the author mentioned around $4/kg of mushrooms. Which makes it par with the retail price. But higher than you can sell it for. In this case, the process will lose money.
The COMPS, on the other side, were at $1.40/kg mushrooms. At this cost level, the COMPS can be profitable. No data were available for the grass-based substrate and the sawdust-based substrate.
With all these numbers in mind, we can now understand why, until today, the alternative substrates haven’t been commercially adopted.
But that is only one part of the equation. To understand the other part, we have to talk about innovation. Let us start with how sustaining and disruptive innovation happens, according to Clayton M. Christensen.
In case you have never heard of him. Christensen was a professor at the Harvard Business School and developed the theory of “disruptive innovation,” which he wrote about in several books.
Besides, he was the co-founder of Rose Park Advisors, a venture capital firm, and Innosight, a management consulting and investment firm specializing in innovation. The first book, for which he is known, is The Innovator’s Dilemma.
If we look at any market, we can distinguish the leader from the rest by looking at their performance. Performance is here a function of a product.
For personal computers, in the beginning, it was clock speed. For hard drives, it was capacity. For cameras, it was the sensor resolution.
Over time the performance of any given product will or at least should improve. If it improves, it is more likely that new markets can be entered, and the product or service can move towards the high-end market.
The first mobile phones were bricks and did not reach the mass markets. But they attracted a specific customer base at the low end of the market that was open using these bricks to communicate. Through sustaining innovation, these phones were getting smaller and smaller. They got more reliable and, therefore, attracted more and more people, aka a new market.
If we look at Apple. Their smartphones are at the high end of the market. But this opens room for competitors to enter the market on the low end. Even if this new smartphone were not as good or as functional as an iPhone. But they satisfied the need for a different demographic, which were more, for example, price-sensitive.
This means sustaining innovation allows a product to enter the high-end of a market. By moving into the high-end market, the product is less likely to fulfill the needs at the lower end. It can and will have features that are of no interest at this level. The increasing gap between market needs at the low-end market and the product gives other products the possibility to enter the market.
What is the performance of the current button mushroom industry?
Color, size, yield, price
With what we know, we can set the entry point of the high market at around 25 kg/m² and or a price point of lower than $1/kg mushroom. We, therefore, can conclude that composted substrate feeds the need of the high-end market. Pun intended.
What is the performance to enter the low-end market?
In our current setting, we can assume that a price point of $2 would fit the need. We now understand why the non-composted substrate struggles to enter the market from the point of innovation.
BUT, according to Christensen, there is another dimension when it comes to innovation. While the model I just talked about describes only the existing market, there is a market currently not served by the industry. Christensen wrote about this new dimension in his book The Innovator’s Solution.
Entering this new market changes everything. The performance of the old market, for example, the price point, is not the benchmark anymore. Instead, other criteria like, for example, environmentally friendly (no odor) or vegan (no manure) will take its place.
Therefore, the non-composted substrates can compete within the button mushroom industry as it serves a different customer base. These customers are more likely to pay a higher price as long as the other criteria are fulfilled. Therefore, the non-composted substrate does not compete with the existing market but serves the new market of non-consumption.
If you are worried that the incumbents will jump into this new market, think twice. There are other factors in place that will prevent or at least reduce the likelihood of it. But that is a topic for another video.
If you are interested to know why the incumbents are less likely to jump into the new market, leave a comment below and upvote the comment.
Talk to you in the next video.
Bechara Mark Anthony. Alternative Mushroom Production System Using Non-composted Grain-based Substrates. PennState Universtiy, 2007. https://etda.libraries.psu.edu/catalog/8066
Colmenares-Cruz, S., Sánchez, J.E. & Valle-Mora, J. Agaricus bisporus production on substrates pasteurized by self-heating. AMB Expr 7, 135 (2017). https://doi.org/10.1186/s13568-017-0438-6 http://creativecommons.org/licenses/by/4.0/
Jóse E Sánchez, Daniel J Royse, Adapting substrate formulas used for shiitake for production of brown Agaricus bisporus, Bioresource Technology, Volume 77, Issue 1, 2001, Pages 65-69, ISSN 0960-8524, https://doi.org/10.1016/S0960-8524(00)00130-9