The science of turning food waste into biofuels is thriving in the lab and in the field, potentially reducing a major global source of landfill methane, according to a recent dispatch in Biofuels Digest.
“Roughly one-third of the food produced in the world for human consumption every year—approximately 1.3 billion tons—gets lost or wasted,” the industry daily reports, citing the UN Food and Agriculture Organization. Much of it ends up in landfills, where it rots in an anaerobic environment and produces methane, an extremely potent greenhouse gas.
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But with awareness of the problem growing, researchers are looking to convert the waste to energy.
Some, like Michael Timko and his team of chemical engineers at Worcester Polytechnic Institute (WPI) in Massachusetts, are working to improve “the yield of oil from the waste food conversion process”, using catalysts to keep carbon compounds from being lost during an early stage in the process when the waste is boiled in water under high pressure.
Ugandan engineering graduate Lawrence Okettayot developed the Sparky Dryer, a food dehydrator that runs on biofuel from a farmer’s garden and burns with zero-carbon emissions. In a country where food loss and waste due to spoilage is a significant issue for farmers, “the dryers start at about $80 and can dehydrate 10 kilograms of mango in two hours, running on two kilograms of biofuel.”
In 2016, a group of researchers in Singapore developed a genetically modified variant of Yarrowia lipolytica yeast that can produce butanol from fats in food waste, a process they say is more efficient and less greenhouse gas-intensive than incineration.
That same year in the UK, tech startup Entomics began collecting Black Soldier flies, giving them food waste to eat, and harvesting them two weeks later. “Acting as a conversion catalyst, their bodies produce an oil that can be transformed into biodiesel, with protein animal feed and fertilizer as byproducts,” the Digest notes. The company is now working with the Sainsbury’s grocery chain to commercialize the process, using the stores’ food waste as a feedstock.