Elucidation of cellulose accessibility, hydrolysability and reactivity as the major limitations in the enzymatic hydrolysis of cellulose

详细信息    查看全文

• 作者：Prabuddha Bansal^a ; Bryan J. Vowell^a ; Mé ; lanie Hall^a ; ^b ; Matthew J. Realff^a ; Jay H. Lee^a ; ^c ; Andreas S. Bommarius^a ; ^d ; ^{Andreas.Bommarius@chbe.gatech.edu}
• 关键词：Accessibility ; Hydrolysability ; Reactivity ; Enzymatic cellulose hydrolysis ; Kinetic modeling
• 刊名：Bioresource Technology
• 出版年：2012
• 出版时间：March 2012
• 年：2012
• 卷：107
• 期：Complete
• 页码：243-250
• 全文大小：1107 K

文摘

The precipitous decline in the rates of enzymatic hydrolysis of cellulose with conversion is one of the major limitations to the commercialization of second-generation biofuel. In this work, various rate-limiting factors (fractal kinetics, changes in crystallinity, accessibility, reactivity and hydrolysable fraction, enzyme clogging, and degree of polymerization) were investigated employing experimental as well as computational studies. Model-guided experiments showed cellulose accessibility and the hydrolysable fraction of accessible substrate (a previously undefined and unreported quantity) to decrease steadily until a conversion level of nearly 70 % , while cellulose reactivity, defined in terms of hydrolytic activity per amount of actively adsorbed cellulase, remained constant. Substrate depletion, accessibility and hydrolysability decrease accounted for approximately 90 % of rate retardation up to 70 % conversion. Faster restart rates were observed on partially converted cellulose as compared to uninterrupted hydrolysis rates, supporting an enzyme clogging phenomenon that could possibly be responsible for the additional rate decrease.