Development of an inducible gene expression system for Lactobacillus sakei


L. Axelsson, MATFORSK, Norwegian Food Research Institute, Osloveien 1, N-1430 Ås, Norway (e-mail:


Aim: To develop an inducible gene expression system for Lactobacillus sakei, based on the regulatory system of sakacin A production.

Methods and Results: A Lactobacillus/Escherichia coli shuttle vector; pKRV3, was constructed including the signal transducing system genes of the bacteriocin sakacin A. The gusA gene fused to PsapA promoter, cloned in this vector allowed for inducible β-glucuronidase expression in L. sakei and L. plantarum following the addition of the sakacin A inducing peptide. PsapA appeared to be a strong and tightly controlled promoter when compared with known promoters.

Conclusion: The pKRV3 system can be used as an inducible gene expression system in lactobacilli.

Significance and Impact of the Study: A novel, inducible gene expression system has been developed for lactic acid bacteria relevant in food fermentations.