Identification of strong promoters based on the transcriptome of Bacillus licheniformis.

ABSTRACT

OBJECTIVES: To expand the repertoire of strong promoters for high level expression of proteins based on the transcriptome of Bacillus licheniformis. RESULTS: The transcriptome of B. licheniformis ATCC14580 grown to the early stationary phase was analyzed and the top 10 highly expressed genes/operons out of the 3959 genes and 1249 operons identified were chosen for study promoter activity. Using beta-galactosidase gene as a reporter, the candidate promoter pBL9 exhibited the strongest activity which was comparable to that of the widely used strong promoter p43. Furthermore, the pro-transglutaminase from Streptomyces mobaraensis (pro-MTG) was expressed under the control of promoter pBL9 and the activity of pro-MTG reached 82 U/ml after 36 h, which is 23% higher than that of promoter p43 (66.8 U/ml). CONCLUSION: In our analyses of the transcriptome of B. licheniformis, we have identified a strong promoter pBL9, which could be adapted for high level expression of proteins in the host Bacillus subtilis.