Fibrobacter succinogenes is an anaerobic bacterium that breaks down plant cell wall biomass in ruminants and converts the cellulose into glucose. Sequenced at the DOE JGI for the Great Lakes Bioenergy Research Center (GLBRC), the 3.8 million base genome was completed and the information submitted to the National Center for Biotechnology Information in late 2009.
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| F. succinogenes is a cellulose-degrading bacterium found in the rumen of animals such as cows and sheep. (Image courtesy of Wikimedia Commons) |
Researchers have found that compared to other known cellulolytic microbes, the bacterium’s genome sequence does not contain known processive cellulase genes, suggesting that F. succinogenes uses novel methods for breaking down cellulose.
Searching for clues to better understand this novel process, F. succinogenes was functionally annotated by many of the same DOE JGI collaborators involved in sequencing the bacterial genome. In a paper published online August 28, 2010 in Applied Biochemistry and Biotechnology, Lucigen’s David Mead and Julie Boyum re-teamed with US Department of Agriculture’s David Stevenson and Paul Weimer and the GLBRC’s Phillip Brumm identified 20 novel cellulose-degrading enzymes and also found that some genes and enzymes involved in breaking down complex sugars function in structures resembling operons.
Additional findings have led the team to theorize that the bacterium may be breaking down cellulose using molecular motors that remove chains of sugars from the cellulose one at a time and then break them down.