Ethanol produced from biological material (biomass) has been identified as a possible energy source to help alleviate our dependence on petroleum-based fuels. Currently, the majority of ethanol produced from fermentation uses corn as its biomass. For ethanol to be produced in larger quantities alternate sources of biomass need to be used.
One of the roadblocks to producing ethanol from other sources of biomass is the multi-step process involved. Complex materials like wood chips, grasses, or other similar materials have had to be broken down into simple sugars before they can be fermented into ethanol.
Now researchers at at the University of Rochester have identified gene sequences that appear to turn on the breakdown of biomass into simple sugars. Making changes to the genome of a bacterium may boost its efficiency as an alcohol producer.
David H. Wu, professor in the Department of Chemical Engineering at the University of Rochester has identified a microorganism named C. thermocellum that has the ability to accomplish both the biomass breakdown and fermentation steps to produce ethanol in a single process. C. thermocellum (shown at left) is not currently used commercially because its biomass conversion process is too inefficient. Wu documented the process by which the C. thermocellum bacterium selects which of over 100 enzymes it will produce to breakdown any given biomass. The results of the selection process activate the appropriate genes in the bacterium to produce more of the correct enzyme for biomass conversion.
Wu is now working to increase the enzyme production by genetically modifying C. thermocellum. He is also scanning the rest of C. thermocellum's genome to find enzyme combinations that will enable it to efficiently ferment grasses, corn stovers, food waste, and other common biomass.
"I don't think this is the revolution that makes ethanol a mainstay," says Wu, "but I believe this is a part of what will lead to the revolution."