Influence of promoter and signal peptide on the expression of pullulanase in Bacillus subtilis

To achieve efficient expression and secretion of a biologically-active pullulanase, the effect of promoter and signal peptide on the production of pullulanase was studied. Three types of promoters (PP43, P apr and P amy ) and four types of signal peptides (SP sacB , SP amy , SP aprl and SP aprs ) were combined to construct twelve expression cassettes for pullulanase in Bacillus subtilis. The pullulanase activity assay was employed to quantify the level of differential expression, and a real-time PCR assay was applied to comparatively track the transcriptional level. Under the same experimental conditions, the potency ratios among the three promoters were P apr  > P amy  > PP43. The secretion efficiency ratios mediated by the signal peptides were SP sacB  > SP amy  > SP aprs  > SP aprl . The highest yield of pullulanase could be achieved under the promotion mediated by P apr and secretion by SP sacB .