Cloning, production and expression of the bacteriocin enterocin A produced by Enterococcus faecium PLBC21 in Lactococcus lactis.

Replacement of the leader sequence of enterocin A (EntA), a bacteriocin produced by Enterococcus faecium PLBC21, by the signal peptide of enterocin P (EntP), a sec-dependent bacteriocin produced by E. faecium P13, permitted production of EntA in Lactococcus lactis. Chimeras encoding the EntP signal peptide (SP( entP )) fused to mature EntA (entA), with or without its immunity gene (entiA), were cloned into the expression vector pMG36c to generate the recombinant plasmids, pMPA15 (SP( entP ):entA) and pMPA10i (SP( entP ):entA + entiA). Transformation of competent L. lactis subsp. lactis IL1403 and L. lactis subsp. cremoris NZ9000 with the recombinant plasmids permitted production of EntA by the transformed cells, and the co-production of nisin A and EntA by the L. lactis subsp. lactis DPC5598 transformants. Mature EntA fused to SP(EntP) is the minimum requirement for synthesis, processing and secretion of biologically active EntA in L. lactis. The production of EntA by most recombinant L. lactis hosts was larger than in the E. faecium control strains. All L. lactis derivatives showed antimicrobial activity against Listeria spp., and L. lactis (pMPA15) displayed the highest antilisterial effect.