“Mining” Cows for New Enzymes to Degrade Biomass


Successful development of biofuels depends on being able to break down cellulose-rich feedstocks such as switchgrass. In nature, enzymes called cellulases break down plant material into simple sugars that can be converted into biofuels. Cattle and other plant eating animals have microbes that carry out this breakdown in the rumen portion of their stomachs. Now scientists at the DOE’s Joint Genome Institute (JGI) report on a metagenomics study of the microbes in the cow rumen. The JGI team was able to obtain and sequence 270 billion DNA bases from the resident microbes feeding on switchgrass in the rumen of a fistulated cow. The researchers developed a candidate set of 30,000 genes that encoded biomass degrading enzymes. They tested a sample of 90 of the proteins encoded by these genes and found that more than 50% had cellulose degrading activity. The JGI researchers were also able to assemble complete genomes of 15 novel microbial species from the cow rumen sample. The research demonstrates that large scale sequencing and data analysis capabilities are enabling researchers to accurately identify genes of biological interest and to provide draft genomes of uncultured novel organisms in the environment. It also defines a powerful strategy for finding new enzymes with significance for DOE missions. The research was led by Matthias Hess of the JGI and is published in the January 28, 2011, issue of Science.

Principal Investigator(s)

Matthias Hess
Joint Genome Institute


Hess, M., A. Sczybra, R. Egan, T.-W. Kim, H. Chokhawala, G. Schroth, S. Luo, D. Clark, F. Chen, T. Zhang, R. Mackie, L. Pennacchio, S. Tringe, A. Visel, T. Woyke, Z. Wang, and E. Rubin. 2011. “Metagenomic Discovery of Biomass-Degrading Genes and Genomes from Cow Rumen,” Science 331, 463–67. DOI: 10.1126/science.1200387.