Characterization and safety evaluation of partially purified bacteriocin produced by Escherichia coli E isolated from fermented pineapple Ananas comosus (L.) Merr

• Published in: Brazilian journal of microbiology 2019-01, Vol.50 (1), p.33-42
• Main Authors: Le, Van Thi, Leelakriangsak, Montira, Lee, Seong Wei, Panphon, Somrak, Utispan, Kusumawadee, Koontongkaew, Sittichai
• Format: Article
• Language: English
• Subjects: Ammonium; Ammonium sulfate; Ananas - metabolism; Ananas - microbiology; Animals; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - metabolism; Anti-Bacterial Agents - pharmacology; Antibacterial activity; Aquaculture; Bacteria; Bacteriocins; Bacteriocins - isolation & purification; Bacteriocins - metabolism; Bacteriocins - pharmacology; Biomedical and Life Sciences; Biotechnology and Industrial Microbiology - Research Paper; Cell Survival - drug effects; Coliforms; Cytotoxicity; E coli; Endopeptidase K; Escherichia coli; Escherichia coli - chemistry; Escherichia coli - genetics; Escherichia coli - metabolism; Fermented food; Food Microbiology; Genomes; Gram-Negative Bacteria - drug effects; Gram-Negative Bacteria - growth & development; Gram-Positive Bacteria - drug effects; Gram-Positive Bacteria - growth & development; Humans; Life Sciences; Medical Microbiology; Mice; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Mycology; NIH 3T3 Cells; Pineapples; Proteinase; Sulfates; Toxicity testing; Virulence
• ISSN: 1517-8382; 1678-4405
• DOI: 10.1007/s42770-018-0014-5

Antibacterial activity of cell-free supernatant from Escherichia coli E against selected pathogenic bacteria in food and aquaculture was the highest against Edwardsiella tarda 3, a significant aquaculture pathogen. Biochemical properties of the bacteriocins were studied and bacteriocin was found to be sensitive to proteinase K, demonstrating its proteinaceous nature. In addition, pH and temperature affected bacteriocin activity and stability. The bacteriocins were partially purified by ammonium sulfate precipitation. The antibacterial activity was only detected in 20% ammonium sulfate fraction and direct detection of its activity was performed by overlaying on the indicator strains. The inhibition zone associated with the antibacterial activity was detected in the sample overlaid by E. tarda 3 and Staphylococcus aureus DMST8840 with the relative molecular mass of about 27 kDa and 10 kDa, respectively. Bacteriocin showed no cytotoxic effect on NIH-3T3 cell line; however, two virulence genes, aer and sfa , were detected in the genome of E. coli E by PCR. The characteristics of bacteriocins produced by E. coli E exhibited the antibacterial activity against both Gram-positive and Gram-negative pathogenic bacteria and the safe use determined by cytotoxicity test which may have interesting biotechnological applications.