Characterization of Mannanase from a Novel Manhahase-Producing Bacterium

摘要

Locust bean gum (LBG) was employed to screen mannanase-producing bacteria. The bacterium with highest mannanase ability was identified as Paenibacillus cookii. It revealed highest activity (6.67 U/mL) when, cultivated in 0.1% LBG with 1.5% soytone and 0.5% tryptone after 4 days incubation at 27 °C. Its mannanase was purified to electrophoretical homogeneity after DEAE-Sepharose and Sephacryl S-100 separation. The purified mannanase, with an N-terminus of GLFGINAY, had pH and temperature optimum at 5.0 and 50 °C, respectively, and was stable at pH 5.0-7.0, ≤50 °C. It was strongly activated by β-mercaptoethanol, dithiothreitol, cysteine, and glutathione, but inhibited by Hg~(2+), Cu~(2+), Zn~(2+), Fe~(3+), PMSF, iodoacetic acid, and EDTA. According to substrate specificity study, the purified mannanase had high specificity to LBG and konjac.