Sunday, August 12, 2012
Columbia Hall, Terrace Level (Washington Hilton)
It is now widely accepted that extremophilic microbes including thermophiles are recognized as one of the most efficient microbial groups in the conversion of solid wastes including lignocellulosic biomass into biofuels e.g., bioethanol, biodiesel, biobutanol, and biogas (e.g., H2). Therefore this study focuses on the enrichment of soil samples for thermophiles (>60 °C) taken from the biosphere of the Sanford Underground Research Facility (SURF) at Homestake in Lead, South Dakota. The enrichment was carried out for aerobic and fermentative thermophiles using seven substrates: untreated prairie cord grass (UPCG), untreated corn stover (UCS), municipal solid waste (MSW), yard compost (YC), coal, lignin, and acetate. After seven transfers, all enriched cultures were tested for liquid and gaseous biofuels and exopolymeric substances (EPS -value added products). Aerobic thermophiles grown on UPCG, UCS, MSW, and YC produced a significant amount of lignocellulose-deconstructing enzymes, in the form of cellulases and xylanases, and EPS. Anaerobic thermophiles grown on UCS and MSW produced a significant amount of hydrogen, in addition to cellulases, xylanases, and EPS. Therefore, our results show that waste materials, including untreated lignocellulosic biomass, can be converted into biofuels and value-added products in one step, which is a novel form of consolidated bioprocessing, using unique thermophiles isolated from SURF.