Cloning,Expression and Characterization of Recombinant β -mannanase from Bacillus subtilis

To achieve the heterologous expression of beta-mannanase which is highly specific to Konjac glucomannan,the beta-mannanase gene BsmanA was cloned from Bacillus subtilis G1,linked to the expression vector pACYCDuet-1 and transformed into E.coil BL21(DE3). The results showed that the full length of the beta-mannanase gene BsmanA was 1098 bp and encoded 366 amino acids. After purification by Ni affinity chromatography,the molecular weight of recombinant enzyme was determined to be 38 kD. The results of enzymatic properties of recombinant beta-mannanase showed that the optimum temperature and pH for the enzymatic reaction were 60℃ and pH6.5.The stability of recombinant beta-mannanase could be maintained in the range of pH4.5~7.0 and temperature 50~70℃. In this study,the heterologous expression of beta-mannanase was accomplished,which would provide a new choice for the industrialization of biocatalytic preparation of mannose oligosaccharides.