Partial characterization of a bacteriocin produced by Lactobacillus helveticus

Aims: To investigate the antimicrobial activity of a strain of Lactobacillu s helveticus. Methods and Results: The culture supernatant fluid Lact. helveticus G51 sho wed antimicrobial activity against thermophilic strains of Lactobacillus. P urification of the active compound was achieved after gel filtration and io n exchange chromatography. As revealed by SDS-PAGE, active fractions were r elatively homogeneous, showing a protein with a molecular mass of 12.5 kDa. The antimicrobial compound was heat labile, inactivated by proteolytic enz ymes and had a bactericidal mode of action. Conclusions: The antimicrobial activity expressed by Lact. helveticus G51 w as correlated with the production of a bacteriocin with properties that wer e different to other helveticins. Significance and Impact of the Study: The study has provided further data o n Lact. helveticus bacteriocins. The strong activity of the bacteriocin tow ards various thermophilic lactobacilli warrants further investigation for i ts potential to obtain attenuated cultures for the enhancement of the chees e-ripening process.