Characterization and antimicrobial spectrum of bacteriocins produced by lactic acid bacteria isolated from traditional Bulgarian dairy products |
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Authors: | ED Simova DB Beshkova ZhP Dimitrov |
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Institution: | Laboratory of Applied Microbiology, Institute of Microbiology, Bulgarian Academy of Sciences, Plovdiv, Bulgaria; LB 'Bulgaricum' Research and Development Centre, Sofia, Bulgaria |
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Abstract: | Aims: To isolate bacteriocin-producing lactic acid bacteria (LAB) with high wide spectrum antibacterial activity and to characterize their inhibitory peptides. Method and Results: Seven LAB strains Lactobacillus casei ssp. rhamnosus (PC5), Lactobacillus delbrueckii ssp. bulgaricus (BB18), Lactococcus lactis ssp. lactis (BCM5, BK15), Enterococcus faecium (MH3), Lactobacillus plantarum (BR12), Lactobacillus casei ssp. casei (BCZ2)], isolated from authentic Bulgarian dairy products were capable of producing bacteriocins, inhibiting the widest range of pathogenic bacteria. The bacteriocins were resistant to heating at 121°C for 15 min, stable at pH 2–10, sensitive to protease, insensitive to α-amylase and lipase. Two of bacteriocins produced by Lact. bulgaricus BB18 (bulgaricin BB18) and E. faecium MH3 (enterocin MH3) were purified and the molecular masses were determined. The N -terminal amino acid sequence of bulgaricin BB18 did not show strong homology to other known bacteriocins. Conclusions: Lactobacillus bulgaricus BB18 and E. faecium MH3 produce two novel bacteriocins highly similar to the pediocin-like nonlantibiotics. Significance and Impact of the Study: The two bacteriocins are potential antimicrobial agents and, in conjunction with their producers, may have use in applications to contribute a positive effect on the balance of intestinal microflora. Furthermore, bulgaricin BB18 strongly inhibits Helicobacter pylori . |
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Keywords: | bacteriocin Enterococcus inhibitory spectrum Lactobacillus Lactococcus |
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