The termite is one of the planet’s most efficient bioreactors
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Researchers at Berkeley Lab’s Joint Genome Institute, California Institute of Technology, and Verenium Corporation have discovered and sequenced over 300 microbes in the hindgut of a Costa Rican termite and identified over 600 genes that encode for enzymes that may play a role in the termite’s conversion of wood mass to sugars. The enzymes could enable more efficient strategies for the production of liquid biofuels from a variety of feedstocks.
Termites are extremely successful at degrading plant biomass including wood and grass, and are therefore important sources of biochemical catalysts that might be used in industrial lignocellulose degradation. Recent research has supported the idea that symbiotic microbes found in the termite hindgut play a direct role in cellulose and xylan hydrolysis – the step that has been the economic bottleneck in man-made systems that convert cellulose to biofuels. In fact, these microbes are so efficient that they are capable of producing about 2 liters of hydrogen from fermentation of a typical sheet of paper.
A relatively small set of fungal enzymes is used today for the hydrolysis of cellulose to simple sugars for subsequent fermentation, but the process is energy intensive, may involve toxic chemicals for pretreatment, and no discernable pathway exists for significant improvement. An optimized cocktail of the new termite-microbe enzymes could lead to conversion that is both energy and chemically efficient.
The Berkeley Lab-ClT-Verenium research is the first system-wide gene analysis of a microbial community specialized towards plant lignocellulose degradation. It revealed that the hindgut of the “higher” Nasutitermes species contains a broad diversity of bacteria representing 12 phyla and 216 phylotypes, and is dominated by two major bacterial lineages, treponemes and fibrobacters. While treponemes have been known to exist in the termite gut, fibrobacters are an exciting new find because they have relatives in the cow rumen known to degrade cellulose and are specialists in this regard.
Berkeley Lab scientists are continuing research on the enzymes in order to define the set of genes with key functional attributes for the breakdown of cellulose and to determine metabolic pathways involved in the processes.
The technology is useful for converting plant lignocellulosic biomass to simple sugars for fermentation into biofuels, and hydrogen. It offers the advantages of being more energy and chemically efficient than the fungal enzymes currently in use and with combinations of the enzymes could be optimized for a particular feedstock
Berkeley Lab co-inventors Phil Hugenholtz and Falk Warnecke.
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The patent pending is available for licensing or collaborative research. Reference Number: Ib-2343
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For More Information:
Warnecke, F. et al, “Metagenomic and Functional Analysis of Hindgut Microbiota of a Wood-Feeding Higher Termite,” Nature 2007, 450, 560-565.
Berkeley Lab’s Joint Genome Institute Press release: