a research team composed of scientists from UCLA and the Oak Ridge National Laboratory have genetically engineered a strain of bacteria that can both digest cellulose directly (without need of various pretreatment regimens) and secrete isobutunol. With this microbe the biofuel biobutanol can be made more efficiently and thus at a lower cost than with the other multiple step methods explored so far (with varying degrees of success).
Their achievement, hopefully, will shorten the time horizon for making a cellulose based biofuel a commercial reality.
http://www.sciencedaily.com/releases/2011/03/110307124917.htmWhile cellulosic biomass like corn stover and switchgrass is abundant and cheap, it is much more difficult to utilize than corn and sugar cane. This is due in large part because of recalcitrance, or a plant's natural defenses to being chemically dismantled.
Adding to the complexity is the fact biofuel production that involves several steps -- pretreatment, enzyme treatment and fermentation -- is more costly than a method that combines biomass utilization and the fermentation of sugars to biofuel into a single process.
To make the conversion possible, Liao and postdoctoral researcher Wendy Higashide of UCLA and Yongchao Li and Yunfeng Yang of Oak Ridge National Laboratory had to develop a strain of Clostridium cellulolyticum, a native cellulose-degrading microbe, that could synthesize isobutanol directly from cellulose. "This work is based on our earlier work at UCLA in building a synthetic pathway for isobutanol production," Liao said.
While some Clostridium species produce butanol, these organisms typically do not digest cellulose directly. Other Clostridium species digest cellulose but do not produce butanol. None produce isobutanol, an isomer of butanol.