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KMID : 0545120120220070930
Journal of Microbiology and Biotechnology
2012 Volume.22 No. 7 p.930 ~ p.938
Isolation, Purification, and Characterization of a Thermostable Xylanase from a Novel Strain, Paenibacillus campinasensis G1-1
Hongchen Zheng

Yihan Liu
Xiaoguang Liu
Jianling Wang
Ying Han
Fuping Lu
Abstract
High levels of xylanase activity (143.98 IU/ml) produced by the newly isolated Paenibacillus campinasensis G1-1 were detected when it was cultivated in a synthetic medium. A thermostable xylanase, designated XynG1-1, from P. campinasensis G1-1 was purified to homogeneity by Octyl-Sepharose hydrophobic-interaction chromatography, Sephadex G75 gel-filter chromatography, and Q-Sepharose ion-exchange chromatography, consecutively. By multistep purification, the specific activity of XynG1-1 was up to 1,865.5 IU/mg with a 9.1-fold purification. The molecular mass of purified XynG1-1 was about 41.3 kDa as estimated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Sequence analysis revealed that XynG1-1 containing 377 amino acids encoded by 1,134 bp genomic sequences of P. campinasensis G1-1 shared 96% homology with XylX from Paenibacillus campinasensis BL11 and 77%~78% homology with xylanases from Bacillus sp. YA- 335 and Bacillus sp. 41M-1, respectively. The activity of XynG1-1 was stimulated by Ca2+, Ba2+, DTT, and ¥â- mercaptoethanol, but was inhibited by Ni2+, Fe2+, Fe3+, Zn2+, SDS, and EDTA. The purified XynG1-1 displayed a greater affinity for birchwood xylan, with an optimal temperature of 60oC and an optimal pH of 7.5. The fact that XynG1-1 is cellulose-free, thermostable (stability at high temperature of 70oC~80oC), and active over a wide pH range (pH 5.0~9.0) suggests that the enzyme is potentially valuable for various industrial applications, especially for pulp bleaching pretreatment.
KEYWORD
Paenibacillus campinasensis, Thermostable Xylanase, Isolation, Purification, Characterization
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