title: Isolation and identification of a novel bacterium, Lactobacillus sakei subsp. dgh strain 5, and optimization of growth condition for highest antagonistic activity.
abstract: In the present study, we isolated Lactobacillus sakei strain DGH5 from raw beef meat. This bacterium plays an inhibitory effect against food-spoiling bacteria and food-borne pathogens, including Listeria monocytogenes, a gram-positive and pathogenic bacterium. Lactobacillus sakei strain DGH5 was identified through both phenotypical and biochemical tests accompanied with 16S rRNA sequence analysis. Among all the sources of carbon, nitrogen and phosphorous forms, we selected the most potent compounds to optimize the condition for the highest antagonistic activity. Among the sugars, polygalacturonic acid demonstrated to improve the antagonistic activity. Ammonium nitrate demonstrated to be suitable nitrogen sources. Amongst phosphorous sources, disodium hydrogen phosphate had the greatest antagonistic effect. According to Taguchi's orthogonal array, temperature, disodium hydrogen phosphate and soy Peptone had significant effect on antagonistic activity. Furthermore, mean comparisons showed that the optimum conditions achieved at pH 6.0, 25 °C temperature, 1.5% (w/v) Na2HPO4and 0.5% (w/v) peptone.
authors.affiliation: Department of Biochemistry, Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran.
authors.forename: Amin
authors.initials: A
authors.lastname: Tashakor
authors.affiliation: Department of Biochemistry, Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran.
authors.forename: Mahshid
authors.initials: M
authors.lastname: Hosseinzadehdehkordi
authors.affiliation: Medicinal Genetics, National Institute of Genetic Engineering and Biotechnology, Iran.
authors.forename: Zeynab
authors.initials: Z
authors.lastname: Emruzi
authors.affiliation: Department of Biochemistry, Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran. Electronic address: gholamid@ut.ac.ir.
authors.forename: Dariush
authors.initials: D
authors.lastname: Gholami
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000898:Antibiosis; D002417:Cattle; D015169:Colony Count, Microbial; D004269:DNA, Bacterial; D005516:Food Microbiology; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000254:growth & development; D006863:Hydrogen-Ion Concentration; D000070256:Latilactobacillus sakei / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification* / Q000502:physiology*; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development; D008460:Meat / Q000382:microbiology; D009566:Nitrates / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D010368:Pectins / Q000037:antagonists & inhibitors; D010461:Peptones / Q000037:antagonists & inhibitors; D010710:Phosphates / Q000037:antagonists & inhibitors; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017421:Sequence Analysis; D013696:Temperature
chemical_list: D004269:DNA, Bacterial; D009566:Nitrates; D010461:Peptones; D010710:Phosphates; D012336:RNA, Ribosomal, 16S; D010368:Pectins; D009584:Nitrogen; C018279:sodium phosphate; C006568:ammonium nitrate; C003181:polygalacturonic acid
keywords: Antagonistic activity; Lactobacillus sakei strain DGH5; Listeria monocytogenes; Taguchi's orthogonal array