The invention belongs to the technical field of
molecular biology, and in particular, relates to a recombinant
bacillus subtilis strain expressing and secreting beta-mannanase efficiently and a methodfor obtaining the strain. Specifically, the method comprises the steps: a codon-optimized beta-mannanase
gene is cloned to the downstreams of different
signal peptide sequences in a pMA5 vector to secrete to
extracellular sites; then restriction factors involved in the process of
secretion are overexpressed in a host
bacteria genome; and finally promoters on the
expression vector are replaced, and the production of beta-mannanase is increased at the level of
protein synthesis by enhancing transcription and translation processes. The recombinant
bacillus subtilis expressing and secreting beta-mannanase efficiently utilizes a 2*SR culture medium for
fermentation production of mannanase under conditions of the temperature of 37 DEG C and the rotating speed of 220 rpm, the highest
enzyme activity of beta-mannanase in 72 h
fermentation broth can reach 2207 U / mL, and the recombinant
bacillus subtilis strain is a strain with good application prospect.