The beer-making process produces mounds of leftover grain, which often ends up being processed into cattle feed or put in landfills. Scientists at State University (Virginia Tech) and Virginia Polytechnic have developed a new method of extracting the protein and fiber from that waste for human use.
The team, led by Dr. Haibo Huang, began by collecting barley grain waste from local breweries. While the substance contains a significant amount of protein, its high fiber content makes it difficult for humans to digest.
The scientists subsequently exposed the waste to a wet milling process, which began with the grain being immersed in a blend of water and alcalase, a liquid enzyme. This caused the grains to soften, allowing their components to be more easily separated during the actual milling stage. Unlike a conventional milling process, the waste didn’t have to be dried out first.
After passing the wet-milled grain through a filter, what remained was a liquid protein concentrate and the leftover fiber from which it had been extracted. This concentrate, which contained 83% of the previously “locked up” protein in the grain, could be used as a sustainable fishmeal alternative for aquaculture feed or nutritional supplements.
In contrast, the fiber could work as a feedstock in biofuel production. In a previous study, researcher Joshua O’Hair treated the fiber with sulfuric acid, causing them to break down into sugars. Those sugars were fed to a bacterium called Bacillus lichenformis, leading to the microbes producing the organic compound 2,3-butanediol – which, among other things, can be used to make butanol fuel.
Dr. Huang’s team is now looking for low-cost enzymes to use in the milling process as they work on scaling up the technology for industrial-capacity use.
Over the past few years, scientists have found some exciting ways to use brewery grain waste. In 2019, a team from Queen’s University in Belfast, Northern Ireland, developed a method to convert spent brewery grain into charcoal. Earlier this year, we saw Trebodur – a biodegradable packaging material made 100% from brewers’ spent grain.
