title: An alkali-tolerant xylanase produced by the newly isolated alkaliphilic Bacillus pumilus from paper mill effluent.
abstract: An alkaline active xylanase, XynBYG, was purified from an alkaliphilic Bacillus pumilus BYG, which was newly isolated from paper mill effluent. It had an optimum pH of 8.0-9.0, and showed good stability after incubated at pH 9.0 for 120 min. The optimum temperature for the activity was 50°C, and the enzyme retained below 55% of its original activity for 30 min at 55°C. The gene coding for XynBYG consists of 687 bp and encodes 229 amino acids. Similarity analysis indicated that XynBYG belong to family 11 glycosyl hydrolases. Site-directed mutagenesis was performed to replace five sites (Tyr/Ser) to Arg/Glu and the results demonstrated that the optimum temperature of the mutant Y7 (S39R-T146E) increased 5°C and the half-life of inactivation (T1/2) at 60 and 65°C was 1 h and 25 min, respectively. Thus, it provides a potential xylanase that can meet the harsh conditions in the industrial applications.
authors: College of Animal Sciences and Technology, Northwest A&F University, 712100, Yangling, People's Republic of China.
authors: Jing
authors: J
authors: Wang
authors: Wei-wei
authors: WW
authors: Zhang
authors: Jin-ni
authors: JN
authors: Liu
authors: Yao-ling
authors: YL
authors: Cao
authors: Xiao-ting
authors: XT
authors: Bai
authors: Yue-sheng
authors: YS
authors: Gong
authors: Pei-lin
authors: PL
authors: Cen
authors: Ming-ming
authors: MM
authors: Yang
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects; D000468:Alkalies / Q000494:pharmacology*; D001407:Bacillus / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification*; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D043364:Endo-1,4-beta Xylanases / Q000096:biosynthesis*; D004795:Enzyme Stability / Q000187:drug effects; D004926:Escherichia coli / Q000187:drug effects / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D005798:Genes, Bacterial / Q000235:genetics; D006863:Hydrogen-Ion Concentration / Q000187:drug effects; D007220:Industrial Waste / Q000032:analysis*; D016297:Mutagenesis, Site-Directed; D010209:Paper; D017422:Sequence Analysis, DNA; D013696:Temperature; D014865:Waste Disposal, Fluid
chemical_list: D000468:Alkalies; D007220:Industrial Waste; D043364:Endo-1,4-beta Xylanases