Natural yeast-derived proteins curb bacterial contamination in ethanol production


In Illinois, researchers at the University of Illinois wondered if they could improve the battle over lactic acid bacteria that is a common issue during corn and sugarcane ethanol production, by having yeast produce a natural, protein to fight the bacterial contamination that can happen during the fermentation process.

“What’s important is that these endolysins, these proteins, can effectively kill these bacteria in a very specific and handy way,” says Michael Miller, associate professor of food microbiology in the Department of Food Science and Human Nutrition (FSHN) at U of I, and co-author of the paper. “It’s also very easy or at least conceivable to engineer the fermenting yeast to make the proteins for us, which potentially makes addressing the bacterial contamination a lot cheaper.

“That was another big contribution of this paper, in that we were able to successfully get yeast to make and secrete endolysins, and make it be antimicrobial in the fermentation broth,” he adds.

Although endolysins have been added to ethanol fermentation before as a purified enzyme, much like adding antibiotics, Miller says their study is the first to report endolysins being made and secreted by the fermenting yeast.