Biofuel from Cows

Scientists have turned to the digestive tract of cows to study how to break down plant matter and convert it into energy. By using genetic materials from a cow’s rumen, the U.S. Department of Agriculture (USDA) has begun developing new ways to break down plant fibers for conversion into biofuel.

To convert switchgrass and corn stover, the leaves and stalks of maize, into biofuel requires the plant fibers to be broken down into sugars. The difficulty comes when cell wall polymers are cross-linked in various ways that make them resistant to breaking down. This finding comes from Dominic Wong, a chemist at the USDA Agricultural Research Service (ARS) Western Regional Research Center, located in Albany, California.

Through previous studies, it was discovered that a unique group of enzymes knows as feruloyl esterases (FAEs) are able to break down key links between the polymers. Studies have also shown that the enzymes are produced by specific types of microbes that degrade plant materials.  Wong collected the microbial population from a cow’s rumen and screened their genetic composition to find which genes produced FAE enzymes.

Wong has worked with scientists at Cargill to isolate, sequence, and clone 12 genes which are capable of being introduced into Escherichia coli for production of the enzymes. These enzymes then can be used to break down the polymeric network in the plant cell wall. Wong and the team of scientists at Cargill have written up a provisional patent application on the FAE genes and enzymes.

Furthermore, the enzymes can also be used to enhance the digestibility and nutritional qualities of animal feed, help with the development of nutritional supplements, and be of use in the development of other value-added products.