title: High-level coproduction of the bacteriocins nisin A and lactococcin A by Lactococcus lactis.
abstract: In this study, a two-plasmid system for enhanced and consistent biosynthesis of the model lactococcal bacteriocin lactococcin A in non-producing Lactococcus lactis hosts was developed. The system comprised a plasmid carrying the genes lcnA and lciA under the control of the nisin-inducible nisA promoter, and a second plasmid harbouring the lcnC and lcnD genes. The introduction of both plasmids into two strains containing the nisRK genes required for nisin-controlled expression, Lc. lactis FI5876 (a nisin A-producer strain) and FI7847, resulted in production of extracellular lactococcin A at a higher level than that for the parental strain, Lc. lactis WM4. In addition, transformation of the nisin-producing host with both plasmids led to a high-level production of both lactococcal bacteriocins, which may provide a means to exploit their complementary properties in cheese ripening.
authors.affiliation: Departamento de Nutrición y Bromatología III, Facultad de Veterinaria, Universidad Complutense de Madrid, 28040 Madrid, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Fernández
authors.forename: Nikki
authors.initials: N
authors.lastname: Horn
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Gasson
authors.forename: Helen M
authors.initials: HM
authors.lastname: Dodd
authors.forename: Juan M
authors.initials: JM
authors.lastname: Rodríguez
mesh_terms: D001430:Bacteriocins / Q000096:biosynthesis* / Q000235:genetics; D003001:Cloning, Molecular; D013294:Lactococcus lactis / Q000235:genetics / Q000378:metabolism*; D009561:Nisin / Q000096:biosynthesis* / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic / Q000235:genetics
chemical_list: D001430:Bacteriocins; C069325:lactococcin A; D009561:Nisin; C102526:nisin A