Leuconostoc lactis strain APC 3969 produces a new variant of cyclic bacteriocin leucocyclicin Q and displays potent anti-Clostridium perfringens activity

Clostridium perfringens is an important foodborne pathogen that produces diverse toxins and is often associated with foodborne gastroenteritis. In this sense, novel biopreservatives with anti-C. perfringens activity are of interest. Among them, bacteriocins produced by lactic acid bacteria stand out as potential candidates. This study describes leucocyclicin C, a novel variant of the bacteriocin leucocyclicin Q, capable of inhibiting C. perfringens. The bacteriocin comprises 61 amino acids, has a molecular mass of 6,081.44 Da, and is produced by the strain Leuconostoc lactis APC 3969. Like many circular bacteriocins, leucocyclicin C has a broad spectrum of activity, is protease resistant, and has high stability against thermic and pH stresses. The leucocyclicin C genetic cluster comprises ten genes instead of the five genes previously described for leucocyclicin Q. Also, this genetic cluster seems to be part of a putative composite transposon. Leucocyclicin C has a minimum inhibitory concentration (MIC) of 3.288 µM against C. perfringens, comparable with other antimicrobial peptides. These results suggest that leucocyclicin C has the potential as a biopreservative for controlling C. perfringens in food.