NEW YORK (GenomeWeb News) - The secrets to making biofuel production far more feasible may reside deep in the belly of the tiny termite, say researchers working with the US Department of Energy’s Joint Genome Institute who have published a metagenomic study of the murky region in Nature.
A group led by the DOE’s Joint Genome Institute and the California Institute of Technology conducted metagenomic shotgun sequencing of the contents of the hindgut of a species of tree-dwelling Costa Rican worker termites, and found 12 different phyla of bacteria inhabiting the area.
These bacteria are essential to the termite’s ability to digest cellulose and lignite, which impede the use of plants as fuel sources.
The JGI and Caltech researchers collaborated with biofuels company Verenium, the National Biodiversity Institute of Costa Rica, and IBM’s Thomas J. Watson Research Center on the study.
Raymond Orbach, JGI’s undersecretary for science, said in a statement that the termite is “a remarkable machine,” that is able to digest “a frightening amount of wood in a very short period of time.”
Orbach said the study allowed JGI to identify some of the “genetic structures” that enable the termite to break down the cell walls of plant materials.
“Our task now is to discover the metabolic pathways generated by these structures to figure out how nature digests plant materials. We can then synthesize the novel enzymes discovered through this project to accelerate the delivery of the next generation of cellulosic biofuels," Orbach said.
JGI used Sanger sequencing to generate around 71 million base pairs from 165 specimens, which were computationally reassembled to identify around a dozen different phyla.
The research team identified two major bacterial lineages, treponemes and fibrobacters, in the hindgut. Treponemes were known to inhabit the termite gut, “but fibrobacters were an exciting new find," said co-author Phil Hugenholtz, head of DOE JGI's Microbial Ecology Program, in a statement. These bacteria are related to species in cow rumen that are known to degrade cellulose, he said, noting that the combination of microbes makes the termite “a mobile miniature bioreactor."
Over 500 genes were located in the hindgut that are related to enzymatic deconstruction of cellulose and hemicellulose. That information has been placed on JGI’s metagenome data management and analysis system for public review.
While the studies of the termite gut have identified structures that could be useful in biofuel production, turning that information into an industrial-scale system will be “far from easy,” said JGI director Eddy Rubin.
"Termites can efficiently convert milligrams of lignocellulose into fermentable sugars in their tiny bioreactor hindguts. Scaling up this process so that biomass factories can produce biofuels more efficiently and economically is another story,” Rubin added.
”To get there, we must define the set of genes with key functional attributes for the breakdown of cellulose, and this study represents an essential step along that path.”