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The adsorption and enzyme activity profiles of specific Trichoderma reesei cellulase/xylanase components when hydrolyzing steam pretreated corn stover

Paper ID Volume ID Publish Year Pages File Format Full-Text
17382 42664 2012 9 PDF Available
Title
The adsorption and enzyme activity profiles of specific Trichoderma reesei cellulase/xylanase components when hydrolyzing steam pretreated corn stover
Abstract

Recycling of enzymes during biomass conversion is one potential strategy to reduce the cost of the hydrolysis step of cellulosic ethanol production. Devising an efficient enzyme recycling strategy requires a good understanding of how the enzymes adsorb, distribute, and interact with the substrate during hydrolysis. We investigated the interaction of individual Trichoderma reesei enzymes present in a commercial cellulase mixture during the hydrolysis of steam-pretreated corn stover (SPCS). The enzyme profiles were followed using zymograms, gel electrophoresis, enzyme activity assays and mass spectrometry. The adsorption and activity profiles of 6 specific enzymes Cel7A (CBH I), Cel7B (EG I), Cel5A (EG II), Xyn 10 (endo-1,4-β-xylanase III), Xyn 11 (endo-xylanase II), and β-glucosidase were characterized. Initially, each of the enzymes rapidly adsorbed onto the SPCS. However, this was followed by partial desorption to an adsorption equilibrium where the Cel7A, Cel7B, Xyn 10, and β-glucosidase were partially adsorbed to the SPCS and also found free in solution throughout the course of hydrolysis. In contrast, the Cel5A and Xyn 11 components remained primarily free in the supernatant. The Cel7A component also exhibited a partial desorption when the rate of hydrolysis leveled off as evidenced by MUC zymogram and SDS-PAGE. Those cellulase components that did not bind to the substrate were generally less stable and lost their activities within the first 24 h when compared to enzymes that were distributed in both the liquid and solid phases. Therefore, to ensure maximum enzyme activity recovery, enzyme recycling seems to be most effective when short-term rounds of hydrolysis are combined with the recovery of enzymes from both the liquid and the solid phases and potentially enzyme supplementation to replenish lost activity.

► Six major enzymes present in Accellerase were isolated and identified. ► Their distribution between the solid and liquid phases during hydrolysis was followed as a precursor to devising possible enzyme recycle strategies. ► All of the enzymes were initially adsorbed followed by partial desorption to varying degrees. ► Cel5A and Xyn11 remain primarily in the liquid phase while Cel7A, Cel7B, Xyn10, and β-glucosidase are present in both phases. ► To maximize enzyme recycle, the enzymes need to be recovered after short-term hydrolysis (24 h) from both the liquid and solid phases.

Keywords
Lignocellulose; Cellulases; Enzymatic hydrolysis; Enzyme adsorption; Enzyme recycle
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The adsorption and enzyme activity profiles of specific Trichoderma reesei cellulase/xylanase components when hydrolyzing steam pretreated corn stover
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 50, Issue 3, 10 March 2012, Pages 195–203
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us