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Site-directed mutagenesis of an Aspergillus niger xylanase B and its expression, purification and enzymatic characterization in Pichia pastoris ☆

Paper ID Volume ID Publish Year Pages File Format Full-Text
35212 45081 2010 6 PDF Available
Title
Site-directed mutagenesis of an Aspergillus niger xylanase B and its expression, purification and enzymatic characterization in Pichia pastoris ☆
Abstract

Xylanase is an important industrial enzyme. In this research, to improve the thermostability and biochemical properties of a xylanase from Aspergillus niger F19, five arginine substitutions and a disulfide bond were introduced by site-directed mutagenesis. The wild-type gene xylB and the mutant gene xylCX8 were expressed in Pichia pastoris. Compare to those of the wild-type enzyme, the optimal reaction temperature for the mutant enzyme increased from 45 °C to 50 °C, the half-life of the mutant enzyme extended from 10 min to 180 min, and the specific activity increased from 2127 U/mg to 3330 U/mg. However, the Vmax and Km of the mutant xylanase decreased. The enzyme activity in broth obtained from shake flask cultures could be induced to 1850 U/mL in 7 days, which is higher than results reported previously. Furthermore, the highest achievable enzyme activity was 7340 U/mL from 140 g/L of biomass in a 3 L fermentor used in our study.

Keywords
Xylanase; Aspergillus niger; Site-directed mutagenesis; Pichia pastoris; Thermostability; Bioreactor
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Site-directed mutagenesis of an Aspergillus niger xylanase B and its expression, purification and enzymatic characterization in Pichia pastoris ☆
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Publisher
Database: Elsevier - ScienceDirect
Journal: Process Biochemistry - Volume 45, Issue 1, January 2010, Pages 75–80
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