Wisconsin researchers double ethanol efficiency with “super yeast”

In Wisconsin, scientists at the University of Wisconsin-Madison and the Great Lakes Bioenergy Research Center (GLBRC) have found a way to nearly double the efficiency with which a commonly used industrial yeast strain converts plant sugars to biofuel. The newly engineered “super yeast” could boost the economics of making ethanol, specialty biofuels and bioproducts.

Though Saccharomyces cerevisiae has been the baker’s and brewer’s yeast of choice for centuries, it poses a unique challenge to researchers using it to make biofuel from cellulosic biomass such as grasses, woods, or the nonfood portion of plants. The world-famous microbe is highly adept at converting a plant’s glucose to biofuel but is otherwise a picky eater, ignoring the plant’s xylose, a five-carbon sugar that can make up nearly half of all available plant sugars.

In a study published October 14 in the journal PLOS Genetics, Sato and his GLBRC collaborators describe the isolation of specific genetic mutations that allow S. cerevisiae to convert xylose into ethanol, a finding that could transform xylose from a waste product into a source of fuel. To uncover these genetic mutations, the researchers had to untangle millions of years of evolution, teasing out what led S. cerevisiae to become so selective in its eating habits in the first place.