CONTROLLED FUNCTIONAL EXPRESSION OF THE CIRCULAR BACTERIOCIN ENTEROCIN NKR-5-3B AND THE LEADERLESS BACTERIOCIN LACTICIN Q

Abstract

Bacteriocins are antimicrobial peptides that possess a number of desirable properties that can be utilized for application in various industries including the food and pharmaceutical industries. Enterocin NKR-5-3B (Ent53B) and lacticin Q (LnqQ) are well characterized bacteriocins that exhibit exceptional stability and potent antimicrobial activity. Here we report the establishment of a dual-plasmid expression system of these bacteriocins by exploiting the quorum sensing production system of nisin known as the nisin inducible controlled expression (NICE^TM) system. Using this dual-plasmid expression system, the production of Ent53B and LnqQ can be controlled by the addition of exogenous nisin at sub-lethal concentration, either in pure or crude form, to induce the transcription of the genes responsible for the production of these bacteriocins. Using this system, cheap cultivation media instead of the commonly used complex and expensive cultivation media, can be utilized in the production of these bacteriocins thereby significantly lowering the production cost – one of the major limiting factors for its large-scale application. Additionally, this system provides a robust control of bacteriocin production thereby creating an effective bacteriocin application delivery system.