Weissella cibaria 110, isolated from the Thai fermented fish product plaa-som, was found to produce a bacteriocin active against some gram-positive bacteria. Bacteriocin activity was not eliminated by exposure to high temperatures or catalase but was destroyed by exposure to the proteolytic enzymes proteinase K and trypsin. The bacteriocin from W. cibaria 110 was purified, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the purified bacteriocin contained one protein band that was approximately 2.5 kDa in size. Mass spectrometry analysis showed the mass of the peptide to be approximately 3,487.8 Da. N-terminal amino acid sequence analysis was performed, and 27 amino acids were identified. Because it has no similarity to other known bacteriocins, this bacteriocin was defined as a new bacteriocin and termed weissellicin 110.Lactic acid bacteria (LAB) have long played important roles in food technology. The LAB include a wide variety of cell types with various physiological and biochemical characteristics. The isolation of LAB from milk products, fermented foods, and plants has frequently been reported. The phylogeny of the bacteria classified currently in the genus Weissella was clarified in 1990 (16), and the taxonomy of Weissella species was further assessed in 1993 (5). Weissella species have been isolated from a variety of sources, and some of them play important roles in fermentation (1). Weissella cibaria was first described by Björkroth et al.(1) and later found in various kinds of fermented foods (6,19).Bacteriocins are peptides produced by bacteria that kill or inhibit the growth of closely related bacteria. Bacteriocins produced by LAB have attracted special interest as potential safe, alternative food preservatives (4,8,15). Many bacteriocins associated with Lactobacillus, Enterococcus, and Leuconostoc species have been described previously (4). However, bacteriocins from Weissella species remain rare, and to our knowledge, no bacteriocins from W. cibaria (1, 9) have been reported previously.W. cibaria 110 (AB261010/DDBJ; DNA Data Bank of Japan [http://www.ddbj.nig.ac.jp/]) isolated from plaa-som (17), a fermented fish product from Thailand, was found to produce a bacteriocin active against some gram-positive bacteria. The present paper describes the purification and analysis of this bacteriocin and discusses its similarities to other known peptides. This is the first study to clarify the characteristics of a W. cibaria bacteriocin. MATERIALS AND METHODSW. cibaria 110. Ten strains of W. cibaria were isolated from plaa-som samples collected from Bangkok, Thailand, and their activities against the indicator strain Lactobacillus sakei JCM 1157 T were determined. Only strain 110 showed activity; this strain was identified using the API 50CHL kit, and the identification was confirmed using 16S rRNA sequence analysis. W. cibaria 110 was therefore used as the bacteriocin-producing strain in this study. Inhibitory activity was determined using the agar well diffusion assay described by ...

Aims:  To investigate the effects of two prebiotics and trehalose on the production of bacteriocins. Methods and Results:  Four carbohydrates [dextrose, fructo‐oligosaccharides (FOS), raffinose, and trehalose] were used as the sole carbon source in a simple broth. Five bacteriocin‐producing strains of bacteria, including those producing nisin, enteriocin, and other bacteriocins, were used, and their inhibitory activities when grown on each carbohydrate were determined. The inhibitory activity assay was performed using the agar well diffusion method, and Lactobacillus sakei JCM 1157T was used as the indicator strain. Effective enhancement of bacteriocin production was observed with FOS and trehalose incubation. Conclusions:  The results suggest that FOS and trehalose can effectively enhance the production of the five kinds of bacteriocins evaluated in this study. Significance and Impact of the Study:  This study offers useful information for not only a new application of FOS and trehalose, but also the potential improvement of food preservation.

Weissella cibaria 110 was isolated from plaa-som, a Thai fermented fish product, and known to produce the weissellicin 110 bacteriocin. We carried out comprehensive comparative genomic analysis of W. cibaria 110 with four other non-bacteriocin-producing W. cibaria strains and identified potential antibiotic-resistant genes. We further identified a type III restriction-modification system, a TA system, and a bacteriocin gene cluster that are unique in W. cibaria 110. Genes related to bacteriocin biosynthesis are organized in clusters and are encoded with minimum genetic machinery consisting of structural cognate immunity genes, including ABC transporter and immunity protein. Finally, we predicted W. cibaria 110 to produce a class IId bacteriocin, weissellicin 110, which is 31 amino acids in length and contains a 21-amino-acid N-terminal leader peptide. This is the first bacteriocin-producing sequencing genome in W. cibaria, and we describe the difference between the bacteriocin-producing and non bacteriocin-producing strains from genome point of view.

Aims:  To characterize bacteriocin‐like inhibitory substances (BLIS) from two dochi‐isolated Enterococcus faecium. Methods and Results:  Enterococcus faecium D081821 and D081833 were isolated from dochi (a traditional fermented food in Taiwan) and found to produce BLIS with inhibitory activities against Listeria monocytogenes, Clostridium perfringens, and Bacillus cereus. Strains D081821 and D081833 showed different growth temperatures and their BLIS showed different sensitivities to heat, proteolytic enzymes, and antibacterial spectra. Both BLIS were collected, partially purified, and analysed by sodium dodecyl sulfate‐polyacrylamide gel electrophoresis (SDS‐PAGE). SDS‐PAGE showed that both partially purified BLIS were approximately 3·0 kDa in size. Conclusions:  These results indicate that E. faecium D081821 and D081833 produce different BLIS with strong antibacterial actions against the tested pathogenic bacteria. Significance and Impact of the Study:  The results of this study suggest that two different BLIS from dochi‐isolated lactic acid bacteria have potential for use as food preservatives.

Aims:  To isolate, characterize and identify lactic acid bacteria (LAB) in the vineyards where koshu grapes, a primary wine grape cultivar in Japan, are grown. Methods and Results:  Sixty samples, including leaves, undamaged grape berries and soil under damaged berries, were collected at four koshu vineyards in Yamanashi Prefecture, Japan. One hundred and 15 acid‐producing cultures were isolated from these samples, and the isolates were divided into classes by phenotype and then into groups by restriction fragment length polymorphism analysis and sequencing of 16S ribosomal DNA (rDNA). Phenotypic and biochemical characteristics identified seven different bacterial groups (A to G). Lactococcus lactis ssp. lactis was the most abundant type of LAB distributed in three koshu vineyards, and Leuconostoc pseudomesenteroides was the most abundant LAB found in the remaining vineyard. Forty‐six isolates produced bacteriocin‐like inhibitory substances (BLIS) against the indicator strain Lactobacillus sakei JCM 1157T. Conclusions:  These results suggest that various LAB are distributed in koshu vineyards, of which a large number produce BLIS. Significance and Impact of the Study:  This is the first report describing the distribution and varieties of LAB that exist in koshu vineyards.