Detection, Purification and Partial Characterization of a Novel Bacteriocin Substance Produced by Lactoccous Lactis Subsp. Lactis B14 Isolated from Boza—bulgarian Traditional Cereal Beverage

Cereals are subjected to fermentation in almost all regions of the world where cereals are consumed as stable food and therefore variety of raw materials and conditions of perspective fermentations are quite large. In these fermentations lactic bacteria are the predominant organisms together with yeasts. Boza is a Bulgarian traditional drink based on cereals widely consumed by people of all ages in the Balkan Penninsula. It is a viscous non-alcoholic beverage, produced from different cereals(or mixture of them) and slightly fermented. Little information is available about its microflora [4]. The aim of using bacteriocins to improve the microbial quality and safety of food has stimulated intensive research efforts in recent years. The best characterized inhibitor to date is nisin, a bacteriocin produced by certain strains of Lactococcus lactis. A number of lactococci exhibit antimicrobial activities different from nisin were isolated from different products [3, 6, 13]. The lactococcal bacteriocins examined so far are all small heat stable proteins that kill closely related bacteria. Some of them desighed as Lactococcin Gal, Lactococcin Gb, Lactococcin A, Lactococcin B [5, 12, 17]. The sequence analysis showed that they belong to different subgroups,of class 2 characterized by their heat stability and dimensions less than 10 kDa [10]. The antagonistic activity of lactic acid strains isolated from boza was performed. As a result of these screening several strains were found to produce bacteriocin like substances. The strain identified by physiological and biochemical techniques and Lactococcus. lactis subsp. lactis B14 was used as producer of antimicrobial substance designed as Bozacin 14. Here we report the characterization of a bacteriocin produced by Lactococcus lactis subsp. lactis with wide inhibitory spectrum including a group of foodborne pathogens.