Discovery could reduce cost of biofuel production

Scientists have demonstrated how to design and genetically engineer enzyme surfaces to bind less with corn stalks and other cellulosic biomass, reducing enzyme costs in the production of biofuels such as ethanol.

A study detailing the research by scientists from Rutgers University-New Brunswick and Michigan State University, has been published in the journal ACS Sustainable Chemistry and Engineering.

"The bottom line is we can cut down the cost of converting biomass into biofuels," Shishir P. S. Chundawat, senior author of the study and an assistant professor in the Department of Chemical and Biochemical Engineering at Rutgers University-New Brunswick, told Science Daily.

The enzymes used to turn switchgrass, corn stover and poplar into biofuel account for roughly 20% of the total biofuel production costs, according to an article appearing in Science Daily. Enzymes cost about 50 cents per gallon of ethanol, so recycling or using fewer enzymes would make biofuels significantly cheaper.

Corn grain is primary feedstock of ethanol, although in recent years some refineries have started to use non-edible parts of corn in ethanol production. "The challenge is breaking down cellulose (plant) material, using enzymes, into sugars that can be fermented into ethanol," Chundawat said. "So any advances on making the enzyme processing step cheaper will make the cost of biofuel cheaper. This is a fairly intractable problem that requires you to attack it from various perspectives, so it does take time."

The Rutgers and Michigan State University researchers showed how specially designed enzymes could be restricted from binding to and being inactivated by lignin. That would ultimately lower enzyme use and make enzyme recycling feasible for biorefineries in the near future, Chundawat told Science Daily.