USDA ARS researchers looking into boost cellulosic biofuel yields

October 21, 2014 |

In Illinois, at the Agricultural Research Service’s Bioenergy Research Unit in Peoria, one recent research focus has been on determining how switchgrass plant maturity at harvest affects ethanol yields. Chemical engineer Bruce Dien led a study that evaluated samples of two different switchgrass varieties that were harvested at three different points in plant development and then pretreated with diluted ammonia. This approach is similar to a treatment used sometimes for enhancing forage quality.

Chemist Michael Bowman led another study that focused specifically on switchgrass xylans. Xylans are polymer chains composed primarily of the sugar xylose. Bowman studied xylan levels at three different stages in switchgrass development to see whether xylan structures change as the plant matures.

Molecular biologist Ron Hector, meanwhile, led work on the microorganisms needed to ferment xylose into ethanol. Xylose is more difficult to convert to ethanol, compared to glucose. Scientists already knew that an enzyme called “D-xylose isomerase,” or XI, is one of several enzymes required to convert xylose into ethanol. But, to date, it has been difficult to harness XI’s conversion potential because of the difficulty of expressing XI in yeast strains and other technical issues.

 

Category: Research

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