Microbial Genetic System Dissects Biomass to Biofuel Conversion

A team of University of Wisconsin-Madison researchers, working with the DOE Great Lakes Bioenergy Research Center (GLBRC), has made a critical step in the development of cost-effective cellulosic biofuels.

Fulfilling the promise of cellulosic biofuels requires developing efficient strategies to extract sugar molecules in biomass polymers like cellulose. Microorganisms such as bacteria and fungi are capable of converting biomass to simple sugars, but historically have been difficult to study using genetic approaches.

The recent breakthrough at the GLBRC has made it possible to perform genetic analysis on Cellvibrio japonicus, a promising bacterium that has long been known to convert biomass to sugars. Using a technique called vector integration, the team has developed a method to generate a mutation in any gene within the organism.

As a test of the technique, the team constructed a mutation that inactivated a key component of a protein complex called a Type II Secretion System, and the disruption of this system prevented the bacterium from efficiently converting biomass into sugars. This proves for the first time that Cellvibrio uses the Type II Secretion System to secrete key enzymes for breakdown of biomass polymerase, thus providing key insight into how this bacterium obtains sugars from biomass.

"Realizing the promise of cellulosic biofuels requires identifying more efficient methods of releasing sugars from biomass", says GLBRC associate scientist David Keating, who led the team. "This new genetic method will allow us to understand how bacteria carry out this conversion, which should provide new avenues for improving the industrial process."

(UW-Madison)