New Yeasts Could Help Fast-Track Biofuel Production

A new yeast that makes ethanol from both five-carbon and six-carbon sugars without needing oxygen has been developed by an Agricultural Research Service (ARS) scientist.

This could be an important breakthrough in industrial ethanol production, because it’s difficult to control oxygen levels as yeasts ferment sugars into ethanol. The new yeast strain would help alleviate this problem.
Producers already make grain ethanol by using yeast to ferment six-carbon plant sugars like glucose. But cost-effective production of cellulosic ethanol will require using both six-carbon and five-carbon sugars in the process.

ARS molecular biologist Stephen Hughes developed the first yeast strain that doesn’t require oxygen to grow on xylose, a five-carbon plant sugar. Hughes works at the ARS National Center for Agricultural Utilization Research in Peoria, Ill.

The new yeast doesn’t directly convert large quantities of xylose into ethanol. Instead, xylose provides energy the yeast needs to grow and reproduce without oxygen. This means that the glucose that might have been used by the yeast to grow and reproduce is now available for fermentation, and the rate of ethanol conversion increases.

Science Daily