Partial photo: Adam Wilson
Brewing beer produces a lot of leftover grain, sometimes turned into bread, crackers and dog biscuits but mostly becoming cattle feed or ending up in landfills. By extracting the protein and fiber from beer waste, scientists have made biofuels and new types of protein sources for food.
About 85% of beer brewing byproducts are spent grains. This wet mash left behind after the sugars have been wrung out from beer brewing grains like barley, wheat, and rye contains about 70% fiber and 14–30% protein. Worldwide breweries produce around 40 million tons of this byproduct every year. The high fiber content makes it hard for humans to digest. Researchers soaked spent brewing grains in water containing a commercially available enzyme alcalase, breaking down the grains and making its components easier to separate. After milling the grain, it was sieved, separating the concentrated liquid protein and a fiber-rich material. A novel wet milling process extracted the protein making it more efficient to turn beer waste into renewable fuels.
The concentrate, containing 83% of the protein in the spent grains, could be used as a low-cost, sustainable alternative protein in processed food products. The leftover fiber could be used as raw material for biofuels. Treating it with sulfuric acid to break it down into sugars the scientists fed them to a new species of which bacteria convert the sugars to a compound used to make rubbers and fuel. They are now trying to scale up the technology for industrial use.
www.anthropocenemagazine.org/2021/04/researchers-have-found-a-way-to-recycle-beer-waste-for-food-and-fuel/?utm_source=rss&utm_medium=rss&utm_campaign=researchers-have-found-a-way-to-recycle-beer-waste-for-food-and-fuel&utm_source=Anthropocene&utm_campaign=26893d61ec-Anthropocene+science+to+AM&utm_medium=email&utm_term=0_ececcea89a-26893d61ec-294331733
Source: Separating beer waste into proteins for foods, and fiber for biofuels, ACS Spring 2021 virtual meeting.