Biofuels From Beer

November 3, 2021

Homebrew enthusiasts and large brewers alike experience the same result of the beer-making process: lots of leftover grain. Once all the flavor has been extracted from the barley and other grains, what remains is a protein and fiber-rich powder that is often used in livestock feed or dumped in landfills. Scientists report a new way to extract protein and fiber from the grain used by brewers and use it to create new types of protein sources, biofuels and more.

The researchers present their results at the spring meeting of the American Chemical Society (ACS). ACS Spring 2021 is held online April 5-30. The live sessions will be held from April 5 to 16, and on-demand and online content will continue until April 30. The meeting features nearly 9,000 presentations on a wide range of scientific topics.

“The brewing industry is in dire need of reducing waste,” says Dr. Haibo Huang, the project’s principal investigator. His team partnered with local brewers to find a way to transform leftover grain into value-added products.

“Leftover grain has a very high percentage of protein compared to other agricultural residues, so our goal was to find a novel way to extract and use it,” explains Yanhong He, a graduate student presenting the work at the meeting. Both Huang and He study at Virginia Polytechnic and State University (Virginia Tech).

Craft beer has become more popular than ever in the U.S. This increased demand has led to increased production, leading to a significant increase in brewery waste, 85% of which is grain used. This by-product contains up to 30% protein and 70% fiber, and although cows and other animals can digest used grain, humans find it difficult to do so because of its high fiber content.

To transform these residues into something more functional, Huang and He developed a novel wet milling fractionation process to separate protein from fiber. Compared to other techniques, the new process is more efficient because researchers do not have to dry the grain first. They tested three commercially available enzymes – alklase, neutrase and pepsin – in this process and found that the alkalse treatment provided the best separation without losing large amounts of any of the components. After a sieving step, the result was a protein concentrate and a product rich in fiber.

Up to 83% of the protein from the used grain was recaptured in the protein concentrate. Initially, the researchers proposed using the extracted protein as a cheaper and more sustainable substitute for fishmeal to feed farmed shrimp. But more recently, Huang and He have begun exploring the use of protein as an ingredient in food products, responding to consumer demand for alternative protein sources.

However, that still left the remaining high fiber product without a specific use. Last year, Huang’s postdoctoral researcher, Dr. Joshua O’Hair, reported the discovery of a new species of  Bacillus lichenformis  in a spring in Yellowstone National Park. In the paper, they observed that the bacteria could convert various sugars into 2,3-butanediol, a compound that is used to make many products, including synthetic rubber, plasticizers and 2-butanol, a fuel. So he pretreated the extracted fiber with sulfuric acid and then decomposed it into cellulose and hemicellulose sugars. He then fed the sugars to the microbe, producing 2,3-butanediol.

Next, the team plans to work on expanding the process of separating protein and fiber components to keep pace with the volume of used grain that is generated in breweries. They are also working with colleagues to determine the economic feasibility of the separation process, as the enzymes currently used to separate the protein and fiber components are expensive. Huang and He hope to find suitable green chemicals and enzymes to make this process even more sustainable, scalable and affordable.

Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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