title: High-level production of a cold-active B-mannanase from Bacillus subtilis BS5 and its molecular cloning and expression.
abstract: Mannanases can be useful in the food, feed, pulp and paper industries. In this research a Bacillus subtilis strain (named Bs5) which produced high-level beta-mannanase was isolated. Maximum level of beta-mannanase (1231.41 U/ml) was reached when Bacillus subtilis Bs5 was grown on konjac powder as the carbon source for nine hours at 32 degrees C. The beta-mannanase was a typical cold-active enzyme and its optimal temperature of 35 degrees C was the lowest among those of the known mannanases from bacteria. In addition, the optimal pH was 5.0 and much wide pH range from 3.0-8.0 was also observed in the beta-mannanase. These properties make the beta-mannanase more attractive for biotechnological applications. The DNA sequence coding the beta-mannanase was cloned and the open reading frame consisted of 1089 bp encoding 362 amino acids. A phylogenetic tree of the beta-mannanase based on the similarity of amino acid sequences revealed that the beta-mannanase formed a cluster with the beta-mannanases of Bacillus subtilis, which was separated from the mannanases of fungi and other bacteria. The beta-mannanase gene could be expressed in Escherichia coli and the recombinant beta-mannanase was characterized by Western blot. This study provided a new source of carbohydrate hydrolysis enzyme with novel characteristics from Bacillus subtilis.
authors.affiliation: College of Bioengineering, Chonqing University, Chongqing 400044. huang_junli@126.com
authors.forename: Jun Li
authors.initials: JL
authors.lastname: Huang
authors.forename: Ling Xiao
authors.initials: LX
authors.lastname: Bao
authors.forename: Han Yan
authors.initials: HY
authors.lastname: Zou
authors.forename: Shu Gang
authors.initials: SG
authors.lastname: Che
authors.forename: Gui Xue
authors.initials: GX
authors.lastname: Wang
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology*; D003001:Cloning, Molecular; D003080:Cold Temperature; D004795:Enzyme Stability; D004926:Escherichia coli; D015964:Gene Expression Regulation, Bacterial; D017422:Sequence Analysis, DNA; D013696:Temperature; D044902:beta-Mannosidase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D044902:beta-Mannosidase