Dynamic changes of substrate reactivity and enzyme adsorption on partially hydrolyzed cellulose.
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. © 2016 Wiley Periodicals, Inc.
Center for Environmental Research and Technology, University of California, 1084 Columbia Avenue, Riverside, CA 92507.|Deconstruction Division, Joint BioEnergy Institute, Emeryville, California.|Department of Biosystems and Agricultural Engineering, University of Kentucky, Lexington, Kentucky.
Jian
J
Shi
Deconstruction Division, Joint BioEnergy Institute, Emeryville, California.|Biological and Materials Science Center, Sandia National Laboratories, Livermore, California.
Dong
D
Wu
Bioproducts, Sciences and Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, Richland, Washington.
Libing
L
Zhang
Deconstruction Division, Joint BioEnergy Institute, Emeryville, California.
Blake A
BA
Simmons
Deconstruction Division, Joint BioEnergy Institute, Emeryville, California.|Biological and Materials Science Center, Sandia National Laboratories, Livermore, California.
Seema
S
Singh
Center for Environmental Research and Technology, University of California, 1084 Columbia Avenue, Riverside, CA 92507.|Bioproducts, Sciences and Engineering Laboratory, Department of Biological Systems Engineering, Washington State University, Richland, Washington.
Bin
B
Yang
Center for Environmental Research and Technology, University of California, 1084 Columbia Avenue, Riverside, CA 92507.|Department of Chemical and Environmental Engineering, Bourns College of Engineering, Riverside, California.|BioEnergy Science Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee.
Charles E
CE
Wyman
D000327:Adsorption; D002480:Cellulase / Q000737:chemistry / Q000378:metabolism*; D002482:Cellulose / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism; D006868:Hydrolysis; D011485:Protein Binding; D014242:Trichoderma / Q000201:enzymology
D005656:Fungal Proteins; D002482:Cellulose; C407024:endoglucanase Cel5A; D002480:Cellulase
cellulase; cellulose; enzyme-substrate interactions; proteolysis; reactivity