(374ag) Production, Characterization and Application of Hydrolytic Lignocellulose-Degrading Enzymes From a Thermophilic Microbial Consortium

Authors: 
Christopher, L. P., South Dakota School of Mines & Technology
Bhalla, A., South Dakota School of Mines & Technology
Muthukumarappan, K., South Dakota State University
Sani, R. K., South Dakota School of Mines & Technology
Zambare, V., South Dakota School of Mines & Technology


The production, characterization and application of a hydrolytic enzyme complex from a thermophilic microbial consortium (TMC) for efficient degradation of lignocellulosic substrates was examined. The production of carboxymethyl cellulase and xylanase was studies on pretreated prairie cord grass and corn stover. The TMC enzyme complex was active and stable in a broad pH (4-10) and temperature (30-800C) range. The optimum temperatures of the TMC cellulase and xylanase were 60 and 70oC, respectively. At 60oC, the half lives of the cellulase and xylanase were 15 and 18 h, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the crude enzyme complex exhibited protein bands of 25-77 kDa. Zymograms revealed multiple enzyme activities containing 3 cellulases and 3 xylanases. The crude enzyme was 77% more active on insoluble crystalline cellulose compared to soluble cellulose. This could have important implications of the TMC enzyme complex in the enzymatic breakdown of lignocellulosic biomass for the establishment of a robust and cost-efficient process for production of lignocellulosic ethanol. It was demonstrated that the lignocellulosic hydrolyzate generated by the TMC enzyme complex could be fermented to bioethanol by a recombinant pentose and hexose fermenting strain.