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ISOLATION AND CHARACTERIZATION OF BACTERIOCIN‐PRODUCING MICROORGANISMS FROM AGOS‐OS
Author(s) -
TAN JULIE D.,
GALVEZ FLOR CRISANTA F.,
TOMITA FUSAO
Publication year - 2000
Publication title -
journal of food safety
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.427
H-Index - 43
eISSN - 1745-4565
pISSN - 0149-6085
DOI - 10.1111/j.1745-4565.2000.tb00296.x
Subject(s) - bacteriocin , biology , microbiology and biotechnology , escherichia coli , bacteria , fermentation , lactococcus lactis , leuconostoc , lactic acid , lactococcus , lactobacillus , enterococcus faecalis , food science , pediococcus , antimicrobial , staphylococcus aureus , biochemistry , genetics , gene
Agos‐os, a fermented meat and sweetpotato mixture, was produced and analyzed for its microbial characteristics. pH decreased during fermentation. Mold and anaerobic bacterial counts increased while yeasts and aerobic bacterial counts decreased during the third and seventh day of fermentation. Six isolates with the widest zones of inhibition on the indicator lawn were selected for bacteriocin production. These isolates had exactly the same morphological, physiological and biochemical characteristics. The ribosomal RNA sequence was 99.5% identical with Enterococcus faecalis VRE 1492. The identification was confirmed through DNA homology test by the EMBL Genbank, Canada. This bacterium produced the L‐isomer lactic acid. The amount of bacteriocin produced by the bacterium was optimized by growing the bacterium at different growth media, initial pH and fermentation time. Maximum production of bacteriocin was achieved in MRS (De Man Rugosa and Sharpe) medium (with glucose) at pH 7.50. The crude bacteriocin inhibited the growth of gram‐positive bacteria such as Lactobacillus sake 15521 and Listeria innocua. The gram‐negative bacteria such as Escherichia coli DH 5‐alpha (with plasmid, PUC) , Salmonella typhii and Staphylococcus aureus were weakly inhibited. Other microorganisms such as Lactobacillus curvatus D31685 , Lactobacillus confusius M23036 , Lactococcus lactis MG1363 , Leuconostoc paramesenteroides S67831 , Pediococcus pentosaceus M58834 , Saccharomyces cerevisiae SS553 (wild type) and Escherichia coli JM109 (no plasmid) were not inhibited.