Researchers at the USDA’s Agricultural Research Service are developing an effective way to break down plant fiber using feruloyl esterases (FAEs), a special group of enzymes found in cow rumen.

Previous studies showed that FAEs are capable of breaking down key links between polymers, and that they are produced by certain types of microbes that degrade plant materials, according to Dominic Wong, lead chemist on the project at the ARS Western Regional Research Center in Albany, Calif. Wong collected the microbial population from cow’s rumen and screened their genetic compositions to find the genes that produce FAE enzymes.

“There are very few gene sequences available for this particular group of enzymes, mainly because there’s no efficient way of screening the genes for microorganisms,” Wong said.

The researchers targeted the linkage between hemicellulose polymers and also between hemicellulose and lignin. The cross-link result was ferulic acid, a component of lignin and a precursor in the manufacture of other aromatic compounds, Wong added.

In collaboration with scientific partners at Cargill Inc., Wong isolated, sequenced and cloned 12 genes capable of being introduced into E. coli for production of the enzymes, which can then be used to break down the polymeric network in plant cell walls. Wong and the Cargill team filed a provisional patent application on the FAE genes and enzymes.

“We tested the enzymes on different substrates, mainly corn stover,” Wong said, adding that his team has worked alongside Cargill on this research for two years now.

Wong said further research is expected to increase conversion efficiency of lignin-rich biomass to simple sugars.

In addition to increasing the efficiency of biomass conversion for cellulosic ethanol production, the enzymes could also be used to enhance digestibility and nutritional qualities of animal feeds, aid in development of nutritional supplements, and more.