Diaper-grown mushrooms to cut down waste
By Darren Quick
September 3, 2014
While their contents might be considered an environmental hazard by many, disposable diapers themselves pose a more significant problem for the environment. According to the EPA, the average baby will work their way through 8,000 of them before they end up in landfill where they'll take centuries to break down. In an effort to reduce the problem, scientists at Mexico's Autonomous Metropolitan University, Azcapotzalco (UAM-A), have turned used diapers to the task of growing mushrooms.
The project led by Rosa María Espinosa Valdemar uses only diapers containing liquid waste, which are first sterilized in an autoclave before being ground up and mixed with material containing lignin from pasture, grape pomace, coffee or pineapple crown to create a substrate.
Fungus spores grown on some wheat or sorghum are then spread on this substrate and placed in a plastic bag, where it is held for two to three weeks in dark conditions with controlled humidity and temperature before being exposed to light. With the mushrooms feeding on the cellulose that is present in the diapers, after a period of two-and-a-half to three months, the diaper degrades and reduces in volume and weight by up to 80 percent.
"For example, if we apply this technology in a kilo (2.2 lb) of diapers, at the end of the process it will be reduced to 200 g (7 oz) and 300 g (11 oz) of mushrooms," says Valdemar Espinosa.
In addition to cellulose, diapers also contain non-biodegradable materials, such as polyethylene, polypropylene, and superabsorbent gel (sodium polyacrylate), which collects fluids. But the plastic materials actually turn out to be beneficial to the growth process, taking up space and providing increased aeration and growing area. Also, the team says that the gel material that retains liquid can be recovered after the mushrooms are harvested for potential use in soils with low moisture retention.
Mushrooms grown from used diapers may not sound that appetizing, but the team was confident enough that they were free of contaminants and infectious organisms that they gave them a taste test.
"We performed an analysis and found that the contents of protein, fat, vitamins and minerals are the same as that of commercial yeast," says Valdemar Espinosa. "It shouldn’t have to be different, mainly because diapers are sterilized."
Despite this, the team doesn't intend mushrooms grown using diapers to end up on dinner plates.
"The project is not intended to produce mushrooms targeted for human consumption, since the main objective is to get rid of diapers to avoid damaging the environment more," Valdemar Espinosa added. "However, the mushrooms could be used as food supplement for cattle, the gel can be used to increase moisture retention in some crops and the plastic can be sent to recycling."
Source: Investigación y Desarrollo via Alpha Galileo