Common baker's yeast, Saccharomyces cerevisiae, is best known for helping ferment beer and leaven bread.
Now, Agricultural Research Service scientists are working to expand on its applications.
At the ARS Southern Regional Research Center, in New Orleans, LA, scientists have altered the yeast's metabolism with plant genes for converting vegetable oil fats (lipids) into value-added byproducts. Eventually, harnessing the yeast's metabolism on an industrial scale could help open new market outlets for oilseed crops, such as soybeans, cotton and linseed, according to John Dyer, a chemist, at the ARS center's Commodity Utilization Research Unit.
Ordinarily, baker's yeast has little need for lipids, except to reinforce cell walls or store energy. It is a diet of sugars and carbohydrates that really gets the yeast going--and producing the carbon dioxide and alcohol that bakers and brewers so desire.
But when modified with desaturase enzymes from plants, including Arabidopis, and then "fed" a diet of vegetable oil fatty acids, the altered yeast's lipid storage increases up to sevenfold. Depending on which desaturases are activated, and the growth conditions scientists create, the yeast's metabolism converts the lipids into valuable byproducts, such as alpha eleostearic acid--a tung oil component--and alpha linolenic acid. The latter byproduct is an omega 3 fatty acid that has been shown to protect against heart disease and cancer.