Characterization and antimicrobial spectrum of bacteriocins produced by lactic acid bacteria isolated from traditional Bulgarian dairy products.
OBJECTIVE
To isolate bacteriocin-producing lactic acid bacteria (LAB) with high wide spectrum antibacterial activity and to characterize their inhibitory peptides.


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 degrees C for 15 min, stable at pH 2-10, sensitive to protease, insensitive to alpha-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.


CONCLUSIONS
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.
Simova
E D
ED
Laboratory of Applied Microbiology, Institute of Microbiology, Bulgarian Academy of Sciences, Plovdiv, Bulgaria.
Beshkova
D B
DB
Dimitrov
Zh P
ZhP
D000595:Amino Acid Sequence; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001430:Bacteriocins / Q000494:pharmacology*; D002031:Bulgaria; D003611:Dairy Products / Q000382:microbiology*; D005516:Food Microbiology; D056546:Lactobacillales / Q000302:isolation & purification* / Q000378:metabolism; D017045:Lactococcus / Q000302:isolation & purification / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D008970:Molecular Weight
D000900:Anti-Bacterial Agents; D001430:Bacteriocins