title: Isolation, purification, and characterization of a thermostable xylanase from a novel strain, Paenibacillus campinasensis G1-1.
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 beta- 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 60 degrees C and an optimal pH of 7.5. The fact that XynG1-1 is cellulose-free, thermostable (stability at high temperature of 70 degrees C~80 degrees C), 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.
authors.affiliation: Key Laboratory of Industrial Fermentation Microbiology, Education Ministry of China, 300457 Tianjin, China.
authors.forename: Hongchen
authors.initials: H
authors.lastname: Zheng
authors.forename: Yihan
authors.initials: Y
authors.lastname: Liu
authors.forename: Xiaoguang
authors.initials: X
authors.lastname: Liu
authors.forename: Jianling
authors.initials: J
authors.lastname: Wang
authors.forename: Ying
authors.initials: Y
authors.lastname: Han
authors.forename: Fuping
authors.initials: F
authors.lastname: Lu
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D003470:Culture Media / Q000737:chemistry; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D020536:Enzyme Activators / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D004795:Enzyme Stability; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D008970:Molecular Weight; D056507:Paenibacillus / Q000201:enzymology* / Q000235:genetics; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature; D014990:Xylans / Q000378:metabolism; D014995:Xylosidases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*
chemical_list: D003470:Culture Media; D004269:DNA, Bacterial; D020536:Enzyme Activators; D004791:Enzyme Inhibitors; D014990:Xylans; D014995:Xylosidases