Thursday, August 14, 2008 - 3:00 PM
S159
Lignocellulosic-Materials Degradation Using Mesophilic and Thermophilic Cultures from the Deep Subsurface of Homestake Mine, Lead, South Dakota
Due to an increasing awareness of problems with crude oil, including price increases, regional instabilities among suppliers, and greenhouse gas impacts, the nationwide support for bioprocessing has been accelerated specifically the biorefinery concept. The Energy Independence and Security Act of 2007 from the White House declared the need for 36 billion gallons per year of biofuel production. To meet these demands, it is critical that all available biomass including lignocellulosic-materials should be transformed into biofuels. One of the best strategies to treat lignocellulosic substrates is to develop cost-effective thermostable enzymatic digestion systems.
In the present study we present the culturable cellulose- and sawdust-degrading mesophilic and thermophilic microbial diversity present in the soil samples collected from the deep subsurface of mine (4850 feet) which is currently known as a NSF Deep Underground Science and Engineering Laboratory (DUSEL); characterization of pure isolates; and the characterization of lignocellulosic substrate hydrolyzing enzymes.
The main findings were 1) majority of the bacteria belonged to Bacillales and Clostridiales; 2) few of the clones were very distantly related to known bacteria and might represent novel lineages; and 3) characterization of cellulases using pure DUSEL cultures (Geobacillus sp. STB2, Geobacillus sp. TERI NSM, Bacillus thuringiensis). Overall, the present work revealed the presence of different bacterial lineages in the unique environment of DUSEL, would provide a novel enzyme cocktail that could be used economically to hydrolyze lignocellulosic substrates, and will improve our overall understanding of the fundamental physical, chemical, and biological parameters that influence lignocellulose hydrolysis under thermophilic conditions.
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