A lot of grain is left behind as a result of brewing. Scientists are using this waste to make environmentally friendly biofuels. Researchers will present their results at the spring meeting of the American Chemical Society (ACS).
“The brewing industry is in dire need of waste reduction,” emphasizes Haibo Huang, Ph.D., the project’s principal investigator. His team teamed up with local breweries to find a way to turn leftover grain into value-added products.
“Waste grain has a very high percentage of protein compared to other agricultural waste. Our goal was to find a new way to extract and use it, ”adds Yanhong He, a graduate student who will present the results of his work at the meeting.
Craft brewing is more popular than ever. The increased demand has led to an increase in production, causing a significant increase in brewery waste, 85% of which is used grain. This byproduct contains up to 30% protein and up to 70% fiber. And while cows and other animals can digest waste grain, it is unsuitable for humans due to its high fiber content.
To turn this waste into something more functional, scientists have developed a new wet-milled fractionation process to separate protein from fiber. Compared to other methods, the new process is more efficient because researchers do not need to pre-dry the grain. They tested three commercially available enzymes in this process – alkalase, neutralase, and pepsin – and found that treatment with alkalase provided better separation without losing large amounts of any of the components. After the screening step, the result was a protein concentrate and a fiber-rich product.
Up to 83% of the protein in the crushed grain is recaptured into the protein concentrate. Researchers initially suggested using it as a cheaper substitute for fishmeal for feeding farm shrimp. But more recently, scientists have begun to investigate the use of protein as an ingredient in foods, meeting consumer demand for alternative sources of protein. However, as a result, the fiber-rich product was still left without much use.
As a result, the bacteria Bacillus lichenformis came in handy. It converts various sugars into 2,3-butanediol, a compound used to make many products such as synthetic rubber, plasticizers, and 2-butanol, a fuel.