title: Cloning, expression, and characterization of a new xylanase from alkalophilic Paenibacillus sp. 12-11.
abstract: A xylanase gene, xyn7c, was cloned from Paenibacillus sp. 12-11, an alkalophilic strain isolated from the alkaline wastewater sludge of a paper mill, and expressed in Escherichia coli. The full-length gene consists of 1,296 bp and encodes a mature protein of 400 residues (excluding the putative signal peptide) that belongs to the glycoside hydrolase family 10. The optimal pH of the purified recombinant XYN7C was found to be 8.0, and the enzyme had good pH adaptability at 6.5-8.5 and stability over a broad pH range of 5.0-11.0. XYN7C exhibited maximum activity at 55 degrees C and was thermostable at 50 degrees C and below. Using wheat arabinoxylan as the substrate, XYN7C had a high specific activity of 1,886 U/mg, and the apparent Km and Vmax values were 1.18 mg/ml and 1,961 μmol/mg/min, respectively. XYN7C also had substrate specificity towards various xylans, and was highly resistant to neutral proteases. The main hydrolysis products of xylans were xylose and xylobiose. These properties make XYN7C a promising candidate to be used in biobleaching, baking, and cotton scouring processes.
authors.affiliation: Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, P. R. China.
authors.forename: Yanyu
authors.initials: Y
authors.lastname: Zhao
authors.forename: Kun
authors.initials: K
authors.lastname: Meng
authors.forename: Huiying
authors.initials: H
authors.lastname: Luo
authors.forename: Peilong
authors.initials: P
authors.lastname: Yang
authors.forename: Pengjun
authors.initials: P
authors.lastname: Shi
authors.forename: Huoqing
authors.initials: H
authors.lastname: Huang
authors.forename: Yingguo
authors.initials: Y
authors.lastname: Bai
authors.forename: Bin
authors.initials: B
authors.lastname: Yao
mesh_terms: D000468:Alkalies / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D043364:Endo-1,4-beta Xylanases / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D004795:Enzyme Stability; D015870:Gene Expression; D007700:Kinetics; D008969:Molecular Sequence Data; D056507:Paenibacillus / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D016415:Sequence Alignment; D012722:Sewage / Q000737:chemistry / Q000382:microbiology; D013379:Substrate Specificity
chemical_list: D000468:Alkalies; D001426:Bacterial Proteins; D012722:Sewage; D043364:Endo-1,4-beta Xylanases