Researchers say grain waste from beer production -- a protein- and fiber-rich powder-like substance -- can be turned into novel protein sources and biofuels, according to a study to be presented Tuesday at the spring meeting of the American Chemical Society.Beer sales have declined in recent years, but it remains the most popular alcoholic beverage in the United States, with the average American adult consuming more than 26 gallons each year.
Currently, after the flavors have been extracted from barley, millet, wheat and other grains, some of the byproduct is used to make cattle feed, but most ends up in landfills.
Scientists turn brewing waste into fresh yeast to make more beer.
Now, scientists have developed a technique for turning the waste material into novel protein sources -- for animals, as well as humans -- and biofuels.
"There is a critical need in the brewing industry to reduce waste," lead investigator Haibo Huang, a postdoctoral researcher at Virginia Tech, said in a press release.
In the beer industry, craft brews have enjoyed a tremendous renaissance over the last two decades, fueling demand for a wide variety of grains -- and yielding large amounts of waste.
According to the latest research, that waste is 70 percent fiber and 30 percent protein. All that fiber is no problem for cows, but it's too much for the human digestive system.
To separate the fiber and protein, researchers developed what's called a wet milling fractionation method. Other separation techniques require the waste grain to be dried, but the new method works with wet grain powder, fresh from the beer processing plant.
After testing a trio of commercially available enzymes, researchers found alcalase separated the fiber and protein most efficiently. Once separated, the grain pulp is sieved, yielding a protein concentrate and a fiber-rich product.
At first, scientists proposed using the protein powder to make fish feed for aquaculture, but more recently, researchers have been experimenting with the powder as a protein source in human food products.
To utilize the fiber-rich product, researchers turned to Bacillus lichenformis, a bacteria species only recently discovered in a spring at Yellowstone National Park.
The bacteria is capable of breaking down sugars in the product into 2,3-butanediol, an organic compound used to make a variety of products, including rubber and biofuel.