Researchers Develop Value-Added Products from Fats, Oils

Biodegradable industrial materials produced by microbial fermentation of vegetable oils and animal fats are being developed by Agricultural Research Service scientists in Wyndmoor, Pa.

The scientists at the ARS Eastern Regional Research Center are using inexpensive fat and oil feedstocks to contain the cost of production. The resulting materials are alternatives to products derived from petroleum feedstocks, according to the ERRC research team of Daniel K.Y. Solaiman, Richard D. Ashby, and Thomas A. Foglia. Ashby presented the findings yesterday at the 222^nd national meeting of the American Chemical Society in Chicago, Ill.

They examined the ability of a bacterium, Pseudomonas resinovorans, to produce poly(hydroxyalkanoate) polymers, or PHAs, when grown on various agricultural oils and fats. Certain microorganisms produce these plastic-like substances as a survival mechanism when fed excessive carbon and deprived of other nutrients.

PHAs naturally break down over time, which makes them suitable for environmentally friendly consumer and medical products ranging from plastics and films to adhesives, depending on the fatty acid composition of the feedstock source, Ashby reported.

These polymers are either rigid or elastomeric, depending on their chemical structure, the organism that produces them and the fat or oil feedstock, according to Ashby. ERRC scientists want to control PHA properties to address suitable industrial uses. They are interested in finding strong yet pliable materials. Recently, they discovered that a related bacterial strain, Pseudomonas oleovorans NRRL B-778, could produce both types of PHA polymer from a single substrate.

In related research, the scientists used a yeast, Candida bombicola, to produce sophorolipids (SLs--microbial surfactants--from simple sugars and a number of oils and fats. Surfactants include such surface-active substances as detergents and emulsifiers. These biosurfactants have properties comparable to chemically produced surfactants, are biodegradable and are not derived from petroleum. The group collaborated with Alberto Nuñez, a research chemist from the same research unit, to develop an analytical method to characterize biosurfactants produced by the yeast.

ARS is the U.S. Department of Agriculture's chief scientific research agency. Solaiman and his colleagues work in the ERRC's Hides, Lipids and Wool Research Unit.