Pilasombut, Komkhae

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Preferred name
Pilasombut, Komkhae
Alternative Name
Pilasombut, K.
Main Affiliation
Email
komkhae.pi@kmitl.ac.th

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    Item type:Publication,
    In vitro characterization of bacteriocin produced by lactic acid bacteria isolated from Nem Chua, a traditional Vietnamese fermented pork
    (2015-08-01)
    Pilasombut, Komkhae
    ;
    Rumjuankiat, Kittaporn
    ;
    Ngamyeesoon, Nualphan
    ;
    Duy, Le Nguyen Doan
    The aim of this study was to screen and In vitro characterize the properties of bacteriocin produced by lactic acid bacteria isolated from Vietnamese fermented pork (Nem chua). One hundred and fifty LAB were isolated from ten samples of Nem chua and screened for bacteriocin-producing lactic acid bacteria. Antimicrobial activity of bacteriocin was carried out by spot on lawn method against both gram positive and gram negative bacteria. One isolate, assigned as KL-1, produced bacteriocin and showed inhibitory activity against Lactobacillus sakei, Leuconostoc mesenteroides and Enterococcus faecalis. To characterize the bacteriocin-producing strain, optimum temperature, incubation period for maximum bacteriocin production and identification of bacteriocin-producing strain were determined. It was found that the optimum cultivation temperature of the strain to produce the maximum bacteriocin activity (12,800 AU/mL) was obtained at 30°C. Meanwhile, bacteriocin production at 6,400 AU/mL was found when culturing the strain at 37°C and 42°C. The isolate KL-1 was identified as L. plantarum. Antimicrobial activity of cell-free supernatant was completely inhibited by proteolytic enzyme of trypsin, alpha-chymotrypsin and proteinase K. Bacteriocin activity was stable at high temperature up to 100°C for 10 min and at 4°C storage for 2 d. However, the longer heating at 100°C and 4°C storage, its activity was reduced.
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    Purification and characterization of a novel plantaricin, KL-1Y, from Lactobacillus plantarum KL-1
    (2015-06-13)
    Rumjuankiat, Kittaporn
    ;
    Perez, Rodney Horanda
    ;
    Pilasombut, Komkhae
    ;
    Keawsompong, Suttipun
    ;
    Zendo, Takeshi
    Three bacteriocins from Lactobacillus plantarum KL-1 were successfully purified using ammonium sulfate precipitation, cation-exchange chromatography and reverse-phase HPLC. The bacteriocin peptides KL-1X, -1Y and -1Z had molecular masses of 3053.82, 3498.16 and 3533.16 Da, respectively. All three peptides were stable at pH 2–12 and 25 °C and at high temperatures of 80 and 100 °C for 30 min and 121 °C for 15 min. However, they differed in their susceptibility to proteolytic enzymes and their inhibition spectra. KL-1Y showed broad inhibitory activities against Gram-positive and Gram-negative bacteria, including Salmonella enterica serovar Enteritidis DMST 17368, Pseudomonas aeruginosa ATCC 15442, P. aeruginosa ATCC 9027, Escherichia coli O157:H7 and E. coli ATCC 8739. KL-1X and -1Z inhibited only Gram-positive bacteria. KL-1X, KL-1Y and KL-1Z exhibited synergistic activity. The successful amino acid sequencing of KL-1Y had a hydrophobicity of approximately 30 % and no cysteine residues suggested its novelty, and it was designated “plantaricin KL-1Y”. Plantaricin KL-1Y exhibited bactericidal activity against Bacillus cereus JCM 2152<sup>T</sup>. Compared to nisin, KL-1Y displayed broad inhibitory activities of 200, 800, 1600, 800, 400 and 400 AU/mL against the growth of Bacillus coagulans JCM 2257<sup>T</sup>, B. cereus JCM 2152<sup>T</sup>, Listeria innocua ATCC 33090<sup>T</sup>, Staphylococcus aureus TISTR 118, E. coli O157:H7 and E. coli ATCC 8739, respectively, whereas nisin had similar activities against only B. coagulans JCM 2257<sup>T</sup> and B. cereus JCM 2152<sup>T</sup>. Therefore, the novel plantaricin KL-1Y is a promising antimicrobial substance for food safety uses in the future.