Bacillus subtilis efficiently-induced expression system based on artificial series promoter

A method, comprising constructing a recombinant plasmid as a regulating and controlling element in an expression host of Bacillus subtilis (B. subtilis), wherein the recombinant plasmid comprises:

• (1) a vector, (2) an artificial series promoter, (3) a gene for coding a repressor, and (4) a repressor-binding DNA fragment located at downstream of a transcriptional start site of the artificial series promoter and capable of being bound to the repressor, and the artificial series promoter comprises PAWH-D30-106, PAH-D75-106 or PAH-D75-106 with nucleotide sequences that are set forth as SEQ ID NO:1, SEQ ID NO:2 and SEQ ID NO:3, respectively;
• wherein the constructing the recombinant plasmid comprises cloning the artificial series promoter, the gene for coding a repressor, and the repressor-binding DNA fragment into the vector that has a target gene of interest, and obtaining the recombinant plasmid;
• wherein the method further comprises transforming the recombinant plasmid into a culture of B. subtilis, growing the culture under a predetermined condition to obtain recombinant clones and inducing expression of the target gene and producing a target protein by growing the recombinant clones under a predetermined inducing condition, wherein adding different amounts of an inducer result in different levels of induced expression of the target gene.