Sunday, May 3, 2009
3-08
Efficiencies of Designed Xylanase Combinations in Releasing Sugars from Hemicellulose Extract on Mixed Northeast Hardwood
One near term option to developing a forest products biorefinery is to carefully pre-extract hemicellulose from incoming wood chips before the main pulping step. This extract can then be fermented to bioethanol or other fermentation products. The release of monomer sugars from a xylan-rich extract, creating a fermentable substrate is a prerequisite for utilization of pulping wood hemicellulose for production of ethanol or other value-added products. Pre-extraction of hemicellulose from northern hardwoods by hot water produces a pH=3.5 extract containing hemicellulose. This project examined the individual and combined effectiveness of six selected, commercial, multicomponent enzyme preparations in catalyzing arabinose and xylose release from hot water hardwood extract: enzyme complex I (from Aspergillus aculeatus), enzyme complex II (from Humicola insolens), xylanase I (from Aspergillus oryzae), xylanase II (from Aspergillus oryzae), xylanase III (from Trichoderma viride), and xylanase IV (from Thermomyces lanuginosus). In this study, different hydrolysis conditions, i.e. enzyme dosage, pH, and temperature, were evaluated for the extent of monomeric sugar yield before fermentation by individual and combined enzyme treatments.
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