title: Characterization of antimicrobial substance from Lactobacillus salivarius KL-D4 and its application as biopreservative for creamy filling.
abstract: Lactobacillus salivarius KL-D4 isolated from duck intestine produced bacteriocin which was stable at high temperature and a wide pH range of 3-10. Its cell free supernatant at pH 5.5 exhibited wide inhibitory spectrum against both G+ and G- bacteria. The highest bacteriocin production was obtained in MRS broth supplemented with 0.5 % (w/v) CaCO3 at 6 h by gentle shaking. PCR walking using specific primers at the conserved region of class-II bacteriocin resulted in 4 known genes of kld1, kld2, kld3 and kld4 with 100 % similarity to genes encoding for salivaricin α, β, induction peptide and histidine protein kinase of Lb. salivarius GJ-24 which did not previously report for bacteriocin characterization, while showing 94, 93, 59 and 62 % to other salivaricin gene cluster, respectively. The high activities of 25,600 AU/ml indicated a strong induction peptide expressed by kld3 which has low similarity to previous inducer reported. Based on operon analysis, only kld1, kld3 and kld4 could be expressed and subsequently elucidated that only salivaricin α like bacteriocin was produced and secreted out of the cells. Using protein purification, only a single peptide band obtained showed that this strain produced one bacteriocin which could be salivaricin α namely salivaricin KLD showing about 4.3 kDa on SDS-PAGE. Partial purification by 20 % ammonium sulfate precipitation of the product was tested on the artificial contamination of creamy filling by Bacillus cereus, Enterococcus faecalis, Pseudomonas stutzeri, Staphylococcus sp. and Stenotrophomonas sp. resulting the growth inhibitory efficiency of 4.45-66.9, 11.5-100, 100, 0-28.1 and 5-100 % respectively. Therefore, salivaricin KLD can be a tentative biopreservative for food industry in the future.
authors.affiliation: Specialized Research Unit, Probiotics and Prebiotics for Health, Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Bangkok, 10900 Thailand ; Center for Advanced Studies for Agriculture and Food (CASAF), Kasetsart University Institute for Advanced Studies (NRU-KU), Kasetsart University, Bangkok, 10900 Thailand.
authors.forename: Phatthanaphong
authors.initials: P
authors.lastname: Therdtatha
authors.affiliation: Specialized Research Unit, Probiotics and Prebiotics for Health, Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Bangkok, 10900 Thailand.
authors.forename: Chanabhorn
authors.initials: C
authors.lastname: Tandumrongpong
authors.affiliation: Division of Animal Production Technology, Faculty of Agricultural Technology, King Mongkut's Institute of Technology Ladkrabang, Bangkok, 10520 Thailand.
authors.forename: Komkhae
authors.initials: K
authors.lastname: Pilasombut
authors.affiliation: Department of Food and Health Sciences, Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto, 862-8502 Japan.
authors.forename: Hiromi
authors.initials: H
authors.lastname: Matsusaki
authors.affiliation: Specialized Research Unit, Probiotics and Prebiotics for Health, Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Bangkok, 10900 Thailand ; Center for Advanced Studies for Agriculture and Food (CASAF), Kasetsart University Institute for Advanced Studies (NRU-KU), Kasetsart University, Bangkok, 10900 Thailand.
authors.forename: Suttipun
authors.initials: S
authors.lastname: Keawsompong
authors.affiliation: Specialized Research Unit, Probiotics and Prebiotics for Health, Department of Biotechnology, Faculty of Agro-Industry, Kasetsart University, Bangkok, 10900 Thailand ; Center for Advanced Studies for Agriculture and Food (CASAF), Kasetsart University Institute for Advanced Studies (NRU-KU), Kasetsart University, Bangkok, 10900 Thailand.
authors.forename: Sunee
authors.initials: S
authors.lastname: Nitisinprasert
keywords: Bakery products; Biopreservative; Creamy filling; Lactobacillus salivarius; Salivaricin