Abstract
The enzymatic hydrolysis of cellulose is a thermodynamically challenging catalytic process that is influenced by both substrate-related and enzyme-related factors. In this study, a proteolysis approach was applied to recover and clean the partially converted cellulose at the different stages of enzymatic hydrolysis to monitor the hydrolysis rate as a function of substrate reactivity/accessibility and investigate surface characteristics of the partially converted cellulose. Enzyme-substrate interactions between individual key cellulase components from wild-type Trichoderma reesei and partially converted cellulose were followed and correlated to the enzyme adsorption capacity and dynamic sugar release. Results suggest that cellobiohydrolase CBH1 (Cel7A) and endoglucanases EG2 (Cel5A) adsorption capacities decreased as cellulose was progressively hydrolyzed, likely due to the “depletion” of binding sites. Furthermore, the degree of synergism between CBH1 and EG2 varied depending on the enzyme loading and the substrates. The results provide a better understanding of the relationship between dynamic change of substrate features and the functionality of various cellulase components during enzymatic hydrolysis. Biotechnol. Bioeng. 2017;114: 503–515.
Original language | English |
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Pages (from-to) | 503-515 |
Number of pages | 13 |
Journal | Biotechnology and Bioengineering |
Volume | 114 |
Issue number | 3 |
DOIs | |
State | Published - Mar 1 2017 |
Bibliographical note
Funding Information:Research conducted by the BioEnergy Science Center (BESC) and Joint BioEnergy Institute (JBEI) was supported by Office of Biological and Environmental in the Office of Science of the U.S. Department of Energy under Contract Numbers DE-PS02-06ER64304 and DE-AC02-05CH11231, respectively. We also acknowledge the Center for Environmental Research and Technology (CE-CERT) of the Bourns College of Engineering for providing the facilities and the Ford Motor Company for funding the Chair in Environmental Engineering that facilitates projects such as this one. Work at WSU was partially funded by DARPA Young Faculty Award contract # N66001-11-1-414, and the authors acknowledge the Bioproducts, Sciences and Engineering Laboratory and Department of Biosystems Engineering at Washington State University for providing facilities and equipment to perform our research. We acknowledge the National Science Foundation under Cooperative Agreement No. 1355438 for partial support of the effort at University of Kentucky. We acknowledge Xiaodi Gao for assisting enzyme adsorption experiments. We thank Drs. Edmund Larenas and Colin Mitchinson from Genencor, a Danisco Division (now DuPont Industrial Biosciences) for generously providing purified CBH1 and EG2 enzymes and offering valuable suggestions to this research.
Publisher Copyright:
© 2016 Wiley Periodicals, Inc.
Keywords
- cellulase
- cellulose
- enzyme–substrate interactions
- proteolysis
- reactivity
ASJC Scopus subject areas
- Biotechnology
- Bioengineering
- Applied Microbiology and Biotechnology