Turning waste to food

Vogt, Jess

Today, while researching possible outlets for scrap wood and furniture at my Goodwill internship, I came across a paper sponsored by the U.S. Department of Agriculture published in 1999 for The International Research Group on Wood Preservation on the possibility of converting wood waste into edible mushrooms. Wood into mushrooms? In the lab? Could this be the epitome of the “waste to food” concept proponents of “cradle to cradle” design so espouse?
In this study, wood waste is inoculated with a certain white-rot fungus from the genus Pleurotus and low concentrations of sugar to stimulate fungi colonization and growth. The “wood wastes” can be conventional wood waste (e.g. leftover materials from construction and demolition), agricultural (e.g. trees, branches, and woody brush), and even paper product waste.
Apparently, a variety of different mushrooms grow well on different compositions of waste material; some grow better on sawdust, while others prefer the corn stocks of agricultural refuge. The fruiting bodies of each mushroom were large – 5-15 cm in diameter – when harvested and could be harvested, or “flushed,” up to ten times at up to 250 grams per flush before the fungi stopped producing fruit.
What’s more impressive is the biological efficiency of this whole process: 1 lb of fresh mushrooms grown in the wild from 1 lb of dry substrate (4 lbs wet) is 100-percent biologically efficient, whereas the mushrooms grown in the wood waste process are between 300- and 500-percent biologically efficient. That means this process is more efficient than nature itself!
But how well did this idea take off? The paper I ran across initially was published in 1999, so I did a little more research to see if there has been any further research on the subject, and – most importantly – to see if anyone is actually growing mushrooms on wood waste.
Turns out, there have been a number of articles published on the economic potential of wood-degrading mushrooms from the Pleurotus genus. Someone has even patented kits for the cultivation of shitake mushrooms on wood waste. An article published in Mushroom News in August of 2007 stated that many specialty mushrooms are now preferentially grown on sawdust substrate.
Who knew that the specialty mushroom you eat in your next gourmet mushroom soup could have been grown on the wood waste from your local construction company? Using wood waste to grow food crops is certainly sustainable and indeed is an example of the “cradle to cradle” production process. “Cradle to cradle” holds that the waste product generated by one industry should be the resource for another industry. This is an expression of the principle more simply know as “one man’s garbage is another man’s gold.”
In a world of increasing pressure on the natural world in the form of rising human consumption and pollution, converting wood waste to food such as mushrooms can be a viable method of dealing with the shortage of landfill space, mitigating the carbon dioxide emissions caused by the burning of wood products and dealing with the growing shortage of natural resources in a world of increasing demand.
As the resource shortages increase, innovations that turn waste into a valuable product are going to be increasingly necessary to sustain our world.
Now, if only someone could convert our old tennis shoes into Cheetos. …
Sources: “Bioconversion of wood wastes into gourmet and medicinal mushrooms” by Suki Croan, from “Proceedings of The International Research Group on Wood Preservation 30th Annual Meeting,” Mushroom News

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