title: Cloning, expression and characterization of a novel salt-tolerant xylanase from Bacillus sp. SN5.
abstract: A xylanase gene (xyn10A) was cloned from Bacillus sp. SN5 and expressed in Escherichia coli. It encoded a 348-residue polypeptide of ~45 kDa. The deduced amino acid sequence had 68 % identity with the endo-1,4-beta-xylanase from Paenibacillus                 lactis 154 that belonged to family 10 of the glycoside hydrolases. Purified recombinant Xyn10A had maximum activity at 40 °C and pH 7.0, with the specific activity of 105 U/mg and a Km of 0.6 mg/ml for beechwood xylan. Xyn10A retained more than 80 % activity between 25 and 45 °C and 29 % activity at 5 °C. It exhibited the highest activity (134 %) in 0.5 M NaCl and still retained 90 % activity in 2.5 M NaCl. It retained about 87 % activity after incubation in 2 M NaCl for 24 h. The cold-active and halo-tolerant properties of Xyn10A make it promising for application in the food industry, especially in the processing of saline food and sea food.
authors.affiliation: National Engineering Lab for Industrial Enzymes, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China. baiwq@im.ac.cn
authors.forename: Wenqin
authors.initials: W
authors.lastname: Bai
authors.forename: Yanfen
authors.initials: Y
authors.lastname: Xue
authors.forename: Cheng
authors.initials: C
authors.lastname: Zhou
authors.forename: Yanhe
authors.initials: Y
authors.lastname: Ma
mesh_terms: D001407:Bacillus / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004795:Enzyme Stability / Q000187:drug effects; D004926:Escherichia coli / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055049:Salt Tolerance; D012965:Sodium Chloride / Q000494:pharmacology; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D012965:Sodium Chloride; D043364:Endo-1,4-beta Xylanases