Researchers for the U.S. Department of Agriculture (USDA) are making advancements on an advanced biofuel, cellulosic ethanol. This article from the USDA says the scientists at the Bioenergy Research Unit in Peoria, Illinois, have recently completed studies on multiple approaches that could help streamline cellulosic ethanol production.

In one study, a team led by ARS chemical engineer Bruce Dien looked at using switchgrass, a perennial grass native to the prairie, for ethanol production. The team concluded that biomass producers could optimize cellulosic ethanol production by planting Kanlow variety—a lowland ecotype—and harvesting at either mid-season or post frost. Results from this study were published in Environmental Technology in 2013.

ARS chemist Michael Bowman led another study of switchgrass xylans, which is challenging to convert to sugars with enzymes because of its complex chemical structure. Bowman determined that structural features of xylan remained the same as the plant matures, even though the amount of xylan changed with maturity. This is good news for biorefiners, because it suggests that they can use the same biomass hydrolyzing enzymes to break down xylans in all switchgrass biomass, no matter when the crop is harvested. Results from this study were published in Metabolites in 2012.

The article also gives progress reports on work with microorganisms needed to ferment xylose—molecules that make up xylans—into ethanol and promising field trials with a yeast strain that grew almost four times faster than other strains that contained XI enzymes and one that could produce ethanol at significantly greater yields than other yeasts engineered to ferment xylose to ethanol.