title: Characterization of endo-β-mannanase from Enterobacter ludwigii MY271 and application in pulp industry.
abstract: β-Mannanases are the second most important enzymes for the hydrolysis of hemicelluloses. An endo-β-mannanase from Enterobacter ludwigii MY271 was purified at 11.7 ± 0.2-fold to homogeneity with a final recovery of 15.2 ± 0.2 %. Using purified β-mannanase protein and SDS-PAGE, the molecular mass was found to be 43.16 kDa. The optimal pH and temperature of the enzyme was found to be 7.0 and 55 °C, respectively. The β-mannanase activity was stable over a broad pH range of pH 2.0-10.0. In addition, the purified enzyme was highly activated by several metal ions and chemical reagents, such as Mg2+, L-cysteine, glutathione (GSH) and β-mercaptoethanol. Whereas the enzyme was strongly inhibited by Hg2+, Cu2+, N-bromosuccinimide (NBS), 1-ethyl-3-(3-dimethyl-amino-propyl)-carbodiimide (EDC), phenylmethanesulfonyl fluoride (PMSF), and sodium dodecyl sulfate (SDS). The β-mannanase was highly active towards glucomannan, and showed endo-activity by producing a mixture of oligosaccharides. Moreover, the enzyme displayed a classical endo-type mode on mannooligosaccharides. The β-mannanase coupled with xylanase significantly improved the brightness of kraft pulp, whereas it has no remarkable effect on the tensile strength of the pulp. Our functional studies of the purified β-mannanase indicate that the enzyme is beneficial to industrial applications, in particular, biotechnological processes, such as food, feed and pulp industry.
authors.affiliation: Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei University of Technology, Wuhan, 430068, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Yang
authors.affiliation: Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei University of Technology, Wuhan, 430068, China. caijun@mail.hbut.edu.cn.
authors.forename: Jun
authors.initials: J
authors.lastname: Cai
authors.affiliation: Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei University of Technology, Wuhan, 430068, China.
authors.forename: Changgao
authors.initials: C
authors.lastname: Wang
authors.affiliation: Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei University of Technology, Wuhan, 430068, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Du
authors.affiliation: Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei Provincial Cooperative Innovation Center of Industrial Fermentation, Hubei University of Technology, Wuhan, 430068, China.
authors.forename: Jianguo
authors.initials: J
authors.lastname: Lin
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D004754:Enterobacter / Q000201:enzymology*; D008361:Mannosidases / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D011134:Polysaccharides; C007916:hemicellulose; D008361:Mannosidases; C119276:endo-beta-mannosidase
keywords: Characterization; End-β-mannanases; Enterobacter ludwigii MY271; Oligosaccharides production