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Identification and Partial Characterization of a Bacteriocin‐Like Inhibitory Substance (BLIS) from Lb. Bulgaricus K41 Isolated from Indigenous Yogurts
Author(s) -
Zaeim Davood,
SoleimanianZad Sabihe,
SheikhZeinoddin Mahmoud
Publication year - 2014
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/1750-3841.12314
Subject(s) - bacteriocin , listeria monocytogenes , listeria , lactobacillus , bacteria , microbiology and biotechnology , chemistry , proteolytic enzymes , antimicrobial , trypsin , food science , biology , biochemistry , enzyme , fermentation , genetics
Forty‐two strains of Lactobacillus bulgaricus isolated from locally made yogurts were examined and compared for bacteriocin producing ability using spot on lawn assay which improved by taking photo and image processing. Lb. bulgaricus K41 exhibited the highest inhibition level against indicators. K41 Bacteriocin‐like inhibitory substance is sensitive to proteolytic enzymes (proteinase K, pepsin, and trypsin) but α‐amylase makes slight reduction in its activity and it is resistant to lipase. This antibacterial peptide is extremely heat‐stable (121 °C for 15 min) and remains active over a wide pH range (pH = 2 to 10); also nonionic detergents (Tween‐20, Tween‐80, and Triton X100) showed no effect on its activity. The inhibitory spectrum is against Gram‐positive bacteria (except Staphylococcus aureus ) with extremely antilisterial activity and it is almost ineffective against Gram‐negative bacteria. The mode of its action was identified as bactericidal against Listeria monocytogenes . The properties of K41 bacteriocin‐like inhibitory substance add to its safety as a biopreservative produced by a generally recognized as safe (GRAS) bacterium suggesting it can be used in hurdle technology for ready‐to‐eat foods as one of the main sources of Listeria contaminations.