In Tennessee, a research team at the Samuel Roberts Noble Foundation, Georgia Tech and Oak Ridge National Laboratory have developed a strain of switchgrass that produces about 33 percent more ethanol than conventional switchgrass. The key – decreasing the presence of lignin by one-eighth – thereby reducing the strain’s resistance – or recalcitrance – to the fermentation process.
Specifically, the team decreased a cellular component – the caffeic acid 3-O-methyltransferase, or COMT, gene – in the Alamo variety of switchgrass. Result? A strain more easily converted to biofuels under milder conditions and with much lower costly additions during fermentation. “The transgenic lines require lower temperature preprocessing,” said research leader Zeng Yu Wang, “and only one-quarter to one-third the level of enzymes for equivalent ethanol fermentation compared to the unmodified switchgrass. This significantly lowers the cost of biofuels and biochemicals from this switchgrass.”