Two Virginia Tech researchers have discovered yeast is good for a lot more than making bread.

A research team led by Xueyang Feng, assistant professor of biological systems engineering, developed a way to make versatile alcohols from yeast, a discovery that could lead to environmentally friendly ways to manufacture a wide range of products that have historically been made with petroleum.

The study that was recently published in Scientific Reports, part of the Nature family of publications, details how the team discovered that a compartment in yeast could be used to produce fatty alcohols in the cell itself.

"Theoretically, in the future these alcohols could be used to supplement the biofuels industry in a more sustainable way," said Jiayuan Sheng, first author on the paper and a post-doctoral associate in the Feng lab. “These fatty alcohols are sometimes derived from petroleum, so using yeast would negate that need for fossil fuels. Right now, however, there are immediate solutions for industries that use fatty alcohols in their production of materials.”

The Department of Biological Systems Engineering is in both the College of Agriculture and Life Sciences and the College of Engineering.

The discovery has myriad industry applications according to Feng.

Fatty, or long- and medium-chain alcohols are used in a wide variety of industries and products, from detergent to ice cream, and are value-added chemicals that generate $3 billion annually. In 2006, more than 1.3 million tons of fatty alcohols were used in everyday consumer products.

“We’re the first to develop this method of using the compartment within yeast cells to create medium-chain alcohols from yeast,” Feng said.

The most common products that incorporate fatty alcohols are cosmetics, lubricants, detergents, and food items that use them as thickeners or emulsifiers.

Fatty alcohols often have an even number of carbon atoms and are categorized by their number. Primary alcohols with chain lengths of 12 to 14 carbons are used to produce personal-care products, detergents, and materials that facilitate the dye process of textiles. C16, for example, is used in cosmetics as cetyl alcohol.

In order to make the medium-chain fatty alcohols, Feng’s team hijacked a pathway in a compartment in a yeast cell. Most eukaryotic cells, or cells containing a nucleus and organelles, are made up of varying microorganisms, including peroxisomes, which are located outside the nucleus in a sea of cytoplasm. Peroxisomes contain enzymes that oxidize certain molecules normally found in a cell, such as fatty and amino acids, and are responsible for turning hydrogen peroxide into water and oxygen. Using a compartmentalized organelle like the peroxisome as a staging ground was what set this study and methodology apart from previous work.

The team found that medium-chain fatty alcohols could be produced in yeast via targeted expression of a fatty acyl-CoA reductase, or TaFAR, in the peroxisome of Saccharomyces cerevisiae.

Bigger than a bread box peroxisomes surely are not, but Feng and Sheng have proven yeast is responsible for a lot more than making toast.

Written by Amy Loeffler

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