Monday, April 30, 2012
Napoleon Ballroom C-D, 3rd fl (Sheraton New Orleans)
Second generation bio-alcohols from lignocellulosic feedstocks are sustainable alternatives to fossil fuels. Decreasing the costs for hydrolytic enzymes would contribute to making bioethanol and other commodities produced from cellulosic substrates less expensive. On-site enzyme production with metabolically versatile filamentous fungi offers an opportunity to exploit residual streams from lignocellulosic biorefineries. The concept of using residual lignocellulosic substances in spent hydrolysates for enzyme production was introduced by Alriksson et al. (Appl Environ Microbiol 2009, 75, 2366–2374), who investigated production of bioethanol and cellulase in sequential fermentation processes based on pretreated spruce and sugarcane bagasse. After fermentation with yeast, recombinant Aspergillus niger was used in a subsequent fermentation step for production of endoglucanase. Cavka et al. studied co-production of bioethanol and xylanase from waste fiber sludge using yeast and recombinant A. niger (J Ind Microbiol Biotechnol 38, 891-899). Trichoderma reesei, an efficient producer of cellulases and xylanases, was studied by Jun et al. with regard to its potential for enzyme production utilizing unconventional carbon sources (Microb Cell Fact 2011, 10, 68).
The present investigation focused on enzyme production by T. reesei grown on media based on pretreated corn cobs, including a corn-cob stillage. Secreted proteins were analyzed using two-dimensional gel electrophoresis to gain a better understanding of the potential of T. reesei for on-site enzyme production from industrial media. The study indicate that sequential fermentations with yeast and filamentous fungi result in efficient utilization of substances solubilized by hydrolysis of lignocellulosics, and that on-site production of hydrolytic enzymes warrants further attention.