Monday, July 25, 2011
Grand Ballroom, 5th fl (Sheraton New Orleans)
The largely available plant-derived lignocellulosic biomass is an attractive source for hydrogen (H2) production but it needs to be hydrolyzed to fermentable sugars before being utilized by most H2 producers. Enzymatic hydrolysis of biomass is still very expensive whereas chemical hydrolysis is often unsuitable for fermentation as it generates microbial growth inhibitory compounds. It would be beneficial if the H2-producing microorganisms could directly utilize the lignocellulosic biomass without a chemical pretreatment for H2 production. The focus of this study was on the isolation of a new thermophilic bacterial strain and its performance in H2 production from switchgrass. A novel, extremely thermophilic bacterium was isolated from Yellowstone National Park, WY. This microorganism produced high levels of H2 when grown at 80°C on switchgrass biomass as a sole carbon source in a mineral salt medium. Subsequent substrate utilization analyses revealed that the isolate was able to utilize many complex polymeric substrates such as cellulose and hemicellulose in addition to C5 and C6 sugars. The major byproducts from the isolate metabolism were H2, CO2, acetate, and lactate. Research is underway to further optimize conditions for H2 production using this promising isolate.