Reply #15: Purdue Yeast Makes Ethanol from Agricultural Waste More Effectively

[Bdog]

http://www.innovations-report.com/html/reports/energy_engineering/report-30711.html

A strain of yeast developed at Purdue University more effectively makes ethanol from agricultural residues that would otherwise be discarded or used as animal feed, and the first license for the yeast has been issued to the biotechnology company Iogen Corp.

Purdue’s genetically altered yeast allows about 40 percent more ethanol to be made from sugars derived from agricultural residues, such as corn stalks and wheat straw, compared with "wild-type" yeasts that occur in nature.

The agricultural residues are primarily made up of cellulose and "hemicellulose," which are known as cellulosic materials. Unlike traditional ethanol feedstocks, such as corn kernels, the cellulosic materials contain two major sugars, glucose and xylose, which cannot both be fermented into ethanol by natural Saccharomyces yeast, the microorganism used by industry to produce ethanol, said Nancy Ho, a senior research scientist and leader of the molecular genetics group in Purdue’s Laboratory of Renewable Resources Engineering, or LORRE. Iogen specializes in producing ethanol from cellulosic material.

A team led by Ho developed the more efficient yeast during the 1980s and 1990s. Conventional yeast can ferment glucose to ethanol, but it cannot ferment xylose. Xylose makes up about 30 percent of t