Sunday , May 16 2021

Separation of beer waste into proteins for food and fiber for biofuels

Note to editors: Announce that this study will be presented at a meeting of the American Chemical Society.

A press conference on the subject will be held on Tuesday, April 6, at 10 a.m. online at

WASHINGTON, Apr 6, 2021 – Home brewing enthusiasts and large producers experience the same brewing process: leftover leftovers. When all the flavor has been extracted from barley and other grains, a protein- and fiber-containing powder remains, which is typically used in cattle or landfilled. Today, researchers are reporting a new way to separate protein and fiber from the grain used by the brewery and use it to create new types of protein sources, biofuels, and more.

“There is a critical need to reduce waste in the brewing industry,” says Haibo Huang, the project’s lead researcher. His team, in collaboration with local breweries, is looking for a way to convert leftovers from grain into value-added products. Researchers will present the results today at a spring meeting of the American Chemical Society (ACS). ACS Spring 2021 will be held online April 5-30. Live sessions will be held from 5 to 16. April, and on-demand and online content will continue until April 30. The meeting will feature nearly 9,000 presentations on a wide range of scientific topics.

“The grain used has a very high percentage of protein compared to other agricultural waste, so our goal was to find a new way to take and use it,” says Yanhong He, a graduate student who will present the work at the meeting. Both Huang and He are at Virginia Polytechnic and State University (Virginia Tech).

The craft brewery has become more popular than ever in the United States. This increased demand has led to an increase in production, which has led to an increase in brewery waste materials, of which 85% has been used for cereals. This by-product contains up to 30% protein and up to 70% fiber, and while cows and other animals may be able to digest the grain used, it is difficult for humans to digest it due to its high fiber content.

To make this waste more functional, Huang and He developed a new wet milling fractionation method to separate protein from fiber. Compared to other techniques, the new process is more efficient because scientists do not have to dry the grain first. In this process, they tested three commercially available enzymes – alkalase, neutrase, and pepsin – and found that the allasase treatment provided the best separation without losing large amounts of each component. After the screening step, the result was a protein concentrate and a fibrous product.

Up to 83% of the cereal protein used was recovered in the protein concentrate. Initially, the researchers suggested using the extracted protein as a cheaper, more sustainable compensation for feeding shrimp grown for fishmeal. But recently, Huang and He have begun to study the use of protein as a food ingredient, meeting consumer demand for alternative protein sources.

However, the remaining fibrous product still left no special use. Last year, Joshua O’Hair, a postdoctoral researcher at Huang, announced the discovery of a new species of Bacillus lichenformis in the spring in Yellowstone National Park. In the paper, they pointed out that bacteria could convert various sugars into 2,3-butanediol, a compound used in the manufacture of many products such as synthetic rubber, plasticizers and 2-butanol. So He pretreated the extracted fiber with sulfuric acid and then decomposed it into sugars from cellulose and hemicellulose. He then fed the sugars to the microbe, producing 2,3-butanediol.

Next, the team plans to work to increase the process of separating the protein and fiber components in order to keep up with the amount of grain used in the breweries. They are also working with their colleagues to determine the economic feasibility of the separation process, as the enzymes currently used to separate protein and fiber components are expensive. Huang and He hope to find suitable enzymes and green chemicals to make the process more sustainable, scalable and cost-effective.

Scholars acknowledge the support and funding of the Southern Sustainable Agriculture Research and Education Graduate Student Grant, the Virginia Agriculture Council, and the John Lee Pratt Graduate Researcher Program.

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