2^nd World Bioenergy Congress and Expo

Biography

Biography: Lew P. Christopher

Abstract

Hydrogen (H2) is considered the “energy of the future” due to its high energy content (143 MJ/Kg) which is 5.3-fold and 3.3-fold higher than that of ethanol and gasoline, respectively, and non-polluting nature, with water as the only product. An environmentally-friendly alternative to the current H2 commercial production via steam reforming of methane is presented through microbial fermentation of simple sugars. However, a production processes based on glucose is not considered cost-competitive as the market price of glucose ($440-600/MT) is approximately 10-fold higher than the cost of lignocellulosics ($39-60/MT). Furthermore, the current cost of lignocellulose conversion to bioenergy (US $15-$25/GJ) exceeds the cost of fossil fuels (US $3.31-$17.37/GJ). A feasible, large-scale production of bio-H2 would require the development of advanced production processes such as Consolidated Bioprocessing (CBP). CBP has been proposed as the ultimate industrial configuration for cost-efficient hydrolysis and fermentation of lignocellulosic biomass. It was demonstrated that the extreme thermophile Caldicellulosiruptor saccharolyticus was able to ferment switchgrass to H2 in one step without any physicochemical or biological pretreatment, whereas H2 production from glucose reached the theoretical maximum for dark fermentation of 4 mol H2/mol glucose. As pretreatment is the single most cost-intensive processing step in biomass bioconversion (25% of total costs on average), combining four processing steps (biomass pretreatment, enzyme production, biomass hydrolysis, biomass fermentation) into a single biorefinery operation makes C. saccharolyticus a promising CBP candidate for sustainable production of H2. The advantages of CBP, thermophiles and low-cost lignocellulosic feedstock for bioenergy production will be reviewed and discussed.