Efficient heterologous expression of alkaline protease SubC in Bacillus subtilis

Abstract:

[Background] Alkaline protease is the enzyme with the largest proportion among industrial enzymes and is widely used in cleaning, food, medical and other industries. Recent studies have found that alkaline protease has great potential in the production of biologically active peptides, which will further broaden its application in the field of health food. [Objective] In this study, Bacillus subtilis was used to heterologously express the alkaline protease SubC derived from Bacillus licheniformis.[Methods] By screening three kinds of Bacillus subtilis host strains (B. subtilis 1A751, MA07 and MA08) and six kinds of signal peptides (AmyE, AprE, NprE, Pel, YddT and YoqM), as well as optimizing the inducer concentration, fermentation medium and fermentation duration, we finally obtained the optimal recombinant strain MA08-AmyE-subC_opt. [Results] The extracellular enzyme activity of the recombinant strain MA08-AmyE-subC_opt was 3.33×10³ AU/mL. Secretory expression level is four times more than that of intracellular soluble protein expression. Compared with the control group WT, the enzyme activity increased by 73.4%.[Conclusion] The heterologous alkaline protease SubC was successfully expressed in Bacillus subtilis, which provided a theoretical basis for the expression of alkaline protease SubC and its industrial application in the field of health food.