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 หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Screening and Identification of Effective Thermotolerant Lactic Acid Bacteria Producing Antimicrobial Activity Against Escherichia coli and Salmonella sp. Resistant to Antib ผู้เขียน: ดร.สุนีย์ นิธิสินประเสริฐ, รองศาสตราจารย์ ,  Veeraphol Nilphai, Phunjai Bunyun, ดร.ประกิต สุขใย, รองศาสตราจารย์ , Katsumi Doi, Kenji Sonomoto สื่อสิ่งพิมพ์:pdf AbstractTwo hundred fifty six isolates of lactic acid bacteria (LAB) displaying antimicrobial activity were isolated from chicken intestine. Twenty effective isolates of LAB show bacteriocin – like activity (BLA) against the target strains resistant to antibiotics (Escherichia coli and Salmonella sp.) to varying degrees. Broad spectrum inhibition specific (SIS) were found from 6 h cultivation while the longer cultivation time of 12 and 24 h appeared either the loss of BLA or the inhibition activity against the different target strain. Only 3 effective thermotolerant isolates, i.e., KUB-AC5, KUB-AC16 and KUB-AC20, exerted broad SIS against all target strains except Salmonella sp. S001. However, BLA belonging to KUB-AC5 could not inhibit growth of E. coli E006 and E010 whereas KUB-AC20 did not inhibit only E. coli E006. Based on biochemical, physiological and molecular systematic method, these isolates were classified as Lactobacillus reuteri. |
หัวเรื่อง:ไม่มีชื่อไทย (ชื่ออังกฤษ : Characterization of Bacteriocin-Producing Lactic Acid Bacteria Strain N1-33 Isolated from Edible Fermented Bamboo Shoot) ผู้เขียน:Melaku Alemu, Panthipa Laemkom, Katsumi Doi, Sadahiro Ohmomo, Mizuo Yajima, ดร.สุนีย์ นิธิสินประเสริฐ, รองศาสตราจารย์ สื่อสิ่งพิมพ์:pdf AbstractLactic acid bacteria (LAB) strain N1-33, isolated from edible fermented bamboo shoot, displayed broad spectrum of inhibitory activity against LAB and other Gram-positive food spoilage and pathogenic bacteria. On the basis of its physiological and biochemical properties together with 16S rRNA sequence analysis, N1-33 was identified as Enterococcus faecalis. It was cultivated in MRS broth at 30?C to early stationary growth phase and the resulting cell-free culture supernatant (CS) showed a maximum inhibitory activity of 12800 AU/ml against Lactobacillus sakei subsp. sakei JCM 1157T, with bactericidal mode of action and concomitant cell lysis. The antibacterial activity of the CS was completely destroyed with proteinase K and partially inactivated with pepsin treatments. Moreover, the study on its physicochemical stability indicated that it was heat tolerant up to 121?C and remained bioactive over a pH range of 2-11. Thus, the spectrum of inhibitory activity, sensitivity to proteolytic enzymes and thermostability of the CS clearly suggested that the bioactive substances had proteinaceous structures and hence classified as bacteriocins. The fact that Enterococcus faecalis N1-33 was isolated from edible fermented bamboo shoot together with these desirable physicochemical properties of its bacteriocin-activity and its ability of metabolizing low cost carbohydrates strongly suggested its great potential for use in food biopreservation. This was known to be the first report of the production of bacteriocins from LAB of fermented bamboo shoot. |
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