Beetle guts to biofuels: Xylome’s quest to lower the cost of cellulosic ethanol

Beetle guts to biofuels: Xylome’s quest to lower the cost of cellulosic ethanol

By Leslie Shown, Great Lakes Bioenergy Research Center

their lab on a 20-acre prairie in Madison, Wisconsin, Xylome scientists are busy tinkering with the yeasts that live in the bellies of wood-boring beetles. A spin-off from the Great Lakes Bioenergy Research Center (GLBRC), Xylome is lowering the cost of making ethanol by creating new yeast strains that more efficiently convert cellulosic biomass to fuel.

While the early stages of biofuel manufacturing focused on fermenting corn grain to ethanol, corn is not the only available feedstock for making biofuel. Cellulosic biomass – i.e., wood, perennial grasses, and the non-food portion of plants – offers another, arguably more sustainable feedstock for fuels.

And yet developing an economically viable cellulosic biofuel pipeline remains a technically challenging endeavor. Compared to corn, the sugars in cellulosic biomass are much more difficult to access and convert to fuel. The sugar xylose, in particular, which accounts for up to 20 –30% of the dry weight of non-food plants, is notoriously difficult to ferment.

“In order to make ethanol out of cellulosic biomass economically,” says Tom Jeffries, Xylome founder and UW–Madison professor emeritus of microbiology and bacteriology, “the technical problem of how to ferment xylose needed to be solved. It’s a problem I’ve worked on for decades.”

It’s also a problem that got a lift in 2006, when Louisiana State University biologist Meredith Blackwell discovered xylose-fermenting yeasts in the guts of wood-boring beetles. Well-acquainted with Jeffries’ research, Blackwell sent him samples of a particularly interesting yeast species she named Spathaspora passalidarum, and it has been the focus of his work ever since. Read more …