The Effect of Cellulose Crystal Structure and Solid-State Morphology on the Activity of Cellulases

[摘要] Consistent with the US-DOE and USDA ???Roadmap??? objective of producing ethanol and chemicals from cellulosic feedstocks more efficiently, a three year research project entitled ???The Effect of Cellulose Crystal Structure and Solid-State Morphology on the Activity of Cellulases??? was initiated in early 2003 under DOE sponsorship (Project Number DE-FG02-02ER15356). A three year continuation was awarded in June 2005 for the period September 15, 2005 through September 14, 2008. The original goal of this project was to determine the effect of cellulose crystal structure, including allomorphic crystalline form (Cellulose I, II, III, IV and sub-allomorphs), relative degree of crystallinity and crystallite size, on the activity of different types of genetically engineered cellulase enzymes to provide insight into the mechanism and kinetics of cellulose digestion by ???pure??? enzymes rather than complex mixtures. We expected that such information would ultimately help enhance the accessibility of cellulose to enzymatic conversion processes thereby creating a more cost-effective commercial process yielding sugars for fermentation into ethanol and other chemical products. Perhaps the most significant finding of the initial project phase was that conversion of native bacterial cellulose (Cellulose I; BC-I) to the Cellulose II (BC-II) crystal form by aqueous NaOH ???pretreatment??? provided an increase in cellulase conversion rate approaching 2-4 fold depending on enzyme concentration and temperature, even when initial % crystallinity values were similar for both allomorphs.

[发布日期] 2014-11-17

[学科分类] 燃料技术