A system for heterologous expression of bacteriocins in Lactobacillus sake

A system for efficient heterologous expression of class II bacteriocins is described that is based on introducing two plasmids in a bacteriocin-negative Lactobacillus sake strain. The first plasmid (pSAK20) contains the genes necessary for transcriptional activation of the Sakacin A promoter as well as export and processing of bacteriocin precursors. The second plasmid (a pLPV111 derivative) contains the structural and immunity genes for the bacteriocin of interest fused to the sakacin A promoter. Using this system, various bacteriocins were produced at levels equal to or higher than those obtained with the corresponding wild-type producer strains.