Biofuel production may get a boost from bacteria

Scientists from the University of Warwick and the University of British Columbia have discovered a lignin-degrading enzyme in bacteria that is capable of breaking down woody plant material, and their findings could make biofuel production more efficient and sustainable.

Biofuels like ethanol play an important role in efforts to increase renewable energy supplies, reduce greenhouse gas emissions and improve energy security.

Presently, ethanol is produced primarily through the fermentation of sugars from crops such as corn and sugar cane. Unfortunately, the use of these crops for fuel production can contribute to rising food prices and deforestation. To alleviate these problems, scientists are striving to develop technologies that will enable the production of ethanol from agricultural waste residues and non-edible crops like switchgrass and fast-growing poplar trees.

Lignin is a chemical compound found in high concentrations in woody plants. Lignin acts to strengthen plant material but it is difficult to break down and can inhibit the production of ethanol from non-edible crops.

In a research project funded in part by the Biotechnology and Biological Sciences Research Council (BBSRC), scientists discovered an enzyme in bacteria that will break down lignin. The bacteria (Rhodococcus jostii) that produce the enzyme live in the soil where they act to degrade plant litter along with other microorganisms such as fungi.

Lignin-degrading enzymes are known to be produced by fungi but this is the first time that these enzymes have been identified in bacteria. Because bacteria grow at a much faster rate than fungi, the production of lignin-degrading enzymes from bacteria would be easier and more commercially viable.

Timothy Bugg from the University of Warwick, who led the research, commented in a press release:

For biofuels to be a sustainable alternative to fossil fuels, we need to extract the maximum possible energy available from plants. By raising the exciting possibility of being able to produce lignin-degrading enzymes from bacteria on an industrial scale, this research could help unlock currently unattainable sources of biofuels.

Further, Duncan Eggar, BBSRC Sustainable Bioenergy Champion, highlighted the importance of the current research in the press release:

Burning wood has long been a significant source of energy. Using modern bioscience we can use woody plants in more sophisticated ways to fuel our vehicles and to produce materials and industrial chemicals. This must all be done both ethically and sustainably. Work like this which develops conversion processes and improves efficiencies is vital.

Dr. Bugg and his research team published their findings about the discovery of a lignin-degrading enzyme in the soil bacterium Rhodococcus jostii in the June 14, 2011 issue of Biochemistry.