Enzyme discovery could aid lignin-based biofuels

| June 16, 2011

University of Warwick professor Timothy Bugg hopes a new lignin-degrading enzyme found in bacteria will help unlock previously unattainable sources of biofuel feedstock. With help from researchers at the University of British Columbia, Bugg has discovered bacteria found in the soil, Rhodococcus jostii, which possess the ability to break down lignin. The research efforts were supported by the Engineering and Physical Research Council and the Biotechnology and Biological Sciences Research Council based in the U.K.

One of the most important aspects of the research, according to Bugg, is the enzyme present in a vehicle like bacteria as opposed to fungi. “Groups have been working on lignin-metabolizing enzymes from fungi since the mid 1980s,” he said, “but I was interested in reports that bacteria could also break down lignin. I think working with bacterial enzymes offers some potential advantage.” Those advantages start with the molecular biology of bacteria, which Bugg pointed out “is more straightforward.” The process to express the recombinant proteins is more straightforward, he said, “and it’s realistic to find thermophillic enzymes that could be very useful for biotechnology.”

The genome sequencing for the enzyme-carrying bacteria has already been completed, creating the possibility for it to be modified more quickly to produce large quantities for commercial use. “We hope that this is the first of a group of lignin-degrading enzymes present in bacteria. The availability of recombinant lignin-degrading enzymes might allow the use of pathway engineering to produce renewable chemicals from lignin,” Bugg said. The impact of a lignin-degrading enzyme could be big for biofuels. “If a biological pretreatment for lignin could be developed then that could be applied to biofuel production from lignocelluloses, and would greatly reduce the energy needed for pretreatment.”

The team will continue to research the enzyme-carrying bacteria but it will also look for similar bacteria strains that might be useful, specifically, those that are more thermostable. To find bacteria that will be suitable for the high heat and pressure requirements of most industrial processes, the team will look at bacteria from places such as volcanic vents.

Duncan Eggar with the BBSRC said on the research that “burning wood had long been a significant source of energy,” but “using modern bioscience we can use woody plants in more sophisticated ways to fuel our vehicles, and to produce materials and industrial chemicals.” Companies like Lignol Corp. are currently developing lignin-based processes for biobased chemicals. “There are many technological hurdles that need to be overcome to make these,” Bugg said, “but the lignin-oxidizing enzymes are key players in this area.”