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Recombinant expression, characterization, and pulp prebleaching property of a Phanerochaete chrysosporium endo-β-1,4-mannanase

Paper ID Volume ID Publish Year Pages File Format Full-Text
18082 42711 2007 8 PDF Available
Title
Recombinant expression, characterization, and pulp prebleaching property of a Phanerochaete chrysosporium endo-β-1,4-mannanase
Abstract

A Phanerochaete chrysosporium cDNA predicted to encode endo-1,4-β-d-mannanase, man5D, was cloned and expressed in Aspergillus niger. The coding region of the gene man5D was predicted to contain, in order from the N-terminal: a secretory signal peptide, cellulose-binding domain, linker region, and glycosyl hydrolase family 5 catalytic site. The enzyme was purified from culture filtrate of A. niger transformants that carried the recombinant man5D. Recombinant Man5D had an apparent molecular size of about 65 kDa by SDS-PAGE, and optimal activity at pH 4.0–6.0 and 60 °C. It was stable from pH 4.0 to 8.0 and up to 60 °C. The enzyme showed affinity for Avicel cellulose, suggesting that the predicted cellulose-binding domain is biologically functional. The specific activities of Man5D on mannan, galactomannan, and glucomannan at pH 5 and 60 °C ranged from 160 to 460 μmol/(min mg), with apparent Km values from 0.54 to 2.3 mg/mL. Product analysis results indicated that Man5D catalyzes endo-cleavage, and appears to have substantial transglycosylase activity. When used to treat softwood kraft pulp, Man5D hydrolyzed mainly glucomannan and exhibited a positive effect as a prebleaching agent. Compared to a commercial prebleaching with xylanase, the prebleaching effect of Man5D was weaker but with reduced loss of fibre yield as determined by the release of solubilized sugars.

Keywords
ACM, active chlorine multiple; CBD, cellulose binding domain; RT-PCR, reverse transcription polymerase chain reaction; SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresisMannanase; Biobleaching; Phanerochaete chrysosporium
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Recombinant expression, characterization, and pulp prebleaching property of a Phanerochaete chrysosporium endo-β-1,4-mannanase
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 41, Issues 6–7, 1 November 2007, Pages 740–747
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