Isolation and characterization of histamine-producing bacteria from fermented fish products.

Histamine is mainly produced by microorganisms that are found in fermented foods, and is frequently involved in food poisoning. Two histamine-producing bacteria were isolated from fermented fish products, anchovy sauce, and sand lance sauce by using a histidine decarboxylating medium. The species were identified as Bacillus licheniformis A7 and B.

An improved process of isomaltooligosaccharide production in kimchi involving the addition of a Leuconostoc starter and sugars.

Isomaltooligosaccharides (IMOs) are α-(1→6)-linked oligodextrans that show a prebiotic effect on Bifidobacterium spp. This study sought to improve IMO synthesis during lactate fermentation in kimchi by inoculating the kimchi fermentation mix with a starter and sugars; the psychrotrophic Leuconostoc citreum KACC 91035 strain with high dextransucrase activity was used as a starter and sucrose (58 mM) and maltose (56 mM) were added as the donor and acceptor for the glucose-transferring reaction of the dextransucrase, respectively. With the addition of both the starter and the sugars and incubation at 10°C, IMOs were produced in kimchi after 3d.

Utilization of galactooligosaccharides by Bifidobacterium longum subsp. infantis isolates.

Prebiotics are non-digestible substrates that stimulate the growth of beneficial microbial populations in the intestine, especially Bifidobacterium species. Among them, fructo- and galacto-oligosaccharides are commonly used in the food industry, especially as a supplement for infant formulas. Mechanistic details on the enrichment of bifidobacteria by these prebiotics are important to understand the effects of these dietary interventions.

Development of a chemically defined minimal medium for the exponential growth of Leuconostoc mesenteroides ATCC8293.

Leuconostoc mesenteroides is a heterofermentative Grampositive bacterium that plays key roles in fermentation of foods such as kimchi, sauerkraut, and milk, leading to the production of various organic acids and aromatic compounds. To study the microbiological and genomic characteristics of L. mesenteroides, we have developed a new chemically defined minimal medium by using the single omission technique.

Characterization of the major dehydrogenase related to d-lactic acid synthesis in Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293.

Leuconostoc mesenteroides subsp. mesenteroides ATCC 8293 is a lactic acid bacterium that converts pyruvate mainly to d-(-)-lactic acid by using d-(-)-lactate dehydrogenase (ldhD). The aim of this study was to identify the gene responsible for d-lactic acid formation in this organism and to characterize the enzyme to facilitate the production of optically pure d-lactic acid.

Enhancing acid tolerance of Leuconostoc mesenteroides with glutathione.

Leuconostoc mesenteroides is a commercially important lactic acid bacterium currently used as a starter for kimchi and kefir. However, its sensitivity to acid stress limits its performance. L.

Bifidobacterium longum subsp. infantis ATCC 15697 α-fucosidases are active on fucosylated human milk oligosaccharides.

Bifidobacterium longum subsp. infantis ATCC 15697 utilizes several small-mass neutral human milk oligosaccharides (HMOs), several of which are fucosylated. Whereas previous studies focused on endpoint consumption, a temporal glycan consumption profile revealed a time-dependent effect.

Construction of theta-type shuttle vector for Leuconostoc and other lactic acid bacteria using pCB42 isolated from kimchi.

The pCB42 plasmid from Leuconostoc citreum CB2567, a strain isolated from kimchi, was characterized, and a shuttle vector for Escherichia coli and lactic acid bacteria (LAB) was constructed. The pCB42 plasmid has a circular structure of 4312bp, a low G+C content, and no single-stranded DNA intermediates during replication, which indicates that pCB42 replicates via the theta-type replication mechanism. In silico analysis of this plasmid revealed 6 open reading frames: 1 transposase gene, 1 DNA-binding gene, 2 putative replication genes, and 2 unknown genes.

Mannitol production by Leuconostoc citreum KACC 91348P isolated from Kimchi.

Leuconostoc genus, which comprise heterofermentative lactic acid bacteria, reduces fructose to mannitol by recycling intracellular NADH. To evaluate the mannitol productivities of different Leuconostoc species, 5 stock cultures and 4 newly isolated strains were cultivated in MRS and simplified media containing glucose and fructose (1:2 ratio). Among them, L.

Buffering effects of calcium salts in kimchi: lowering acidity, elevating lactic acid bacterial population and dextransucrase activity.

This study investigates the buffering effects of calcium salts in kimchi on total acidity, microbial population, and dextransucrase activity. Calcium chloride or calcium carbonate was added in dongchimi-kimchi, a watery-radish kimchi, and their effects on various biochemical attributes were analyzed. The addition of 0.

Cloning of dextransucrase gene from Leuconostoc citreum HJ-P4 and its high-level expression in E. coli by low temperature induction.

A dextransucrase (LcDS) gene from Leuconostoc citreum HJ-P4 has been amplified and cloned in E. coli. The LcDS gene consists of 4,431 nucleotides encoding 1,477 amino acid residues sharing 63-98% of amino acid sequence identities with other known dextransucrases from Leuc.

Production of L-lactate in Leuconostoc citreum via heterologous expression of L-lactate dehydrogenase gene.

D-form lactate is often found in fermented foods and excessive dietary intake of D-lactate may cause metabolic stress in both infants and patients. Leuconostoc citreum is a major lactic acid bacterium that produces D-lactate in fermented foods. The aim of this study was to change the pyruvate carbon flux in L.

Heterologous expression and secretion of Lactobacillus amylovorus alpha-amylase in Leuconostoc citreum.

To develop a gene expression system for Leuconostoc genus, construction of expression vector and expression of a heterologus protein in Leuconostoc was performed. Alpha-amylase gene from Lactobacillus amylovorus was cloned into a Leuconostoc cloning vector, pLeuCM, with its own signal peptide. pLeuCMamy was introduced into Leuconostoc citreum CB2567 and a successful expression of alpha-amy gene was confirmed by enzyme activity assays.

Leuconostoc citreum HJ-P4 (KACC 91035) regulates immunoglobulin E in an ovalbumin-induced allergy model and induces interleukin-12 through nuclear factor-kappa B and p38/c-Jun N-terminal kinases signaling in macrophages.

Leuconostoc citreum (L. citreum) HJ-P4 (KACC 91035) is one of the major predominant species in kimchi fermentation in Korea. The purpose of the present study was to test the immunomodulatory capacity of L.

Induction of Th1 cytokines by Leuconostoc mesenteroides subsp. mesenteroides (KCTC 3100) under Th2-type conditions and the requirement of NF-kappaB and p38/JNK.

Leuconostoc mesenteroides subsp. mesenteroides (LMM) KCTC 3100, is one of the prominent species in the fermentation of kimchi, a traditional Korean food. In the present study, we investigated the capacity of this microorganism in inducing Th1 cytokines in the presence of Th2 signals in vitro and in vivo and the requirement of NF-kappaB and MAPK signaling.

Diversity analysis of lactic acid bacteria in takju, Korean rice wine.

To investigate the lactic acid bacterial population in Korean traditional rice wines, biotyping was performed using cell morphology and whole-cell protein pattern analysis by SDSPAGE, and then the isolates were identified by 16S rRNA sequencing analysis. Based on the morphological characteristics, 103 LAB isolates were detected in wine samples, characterized by whole-cell protein pattern analysis, and they were then divided into 18 patterns. By gene sequencing of 16S rRNA, the isolates were identified as Lactobacillus paracasei, Lb.

Optimized substrate concentrations for production of long-chain isomaltooligosaccharides using dextransucrase of Leuconostoc mesenteroides B-512F.

Isomaltooligosaccharide (IMO) is a promising dietary component with prebiotic effect, and the long-chain IMOs are preferred to short chain ones owing to the longer persistence in the colon. To establish the optimal process for synthesis of long-chain IMOs, we systematically examined the reaction condition of dextransucrase of Leuconostoc mesenteroides B-512F by changing the ratio of sucrose to maltose (varying as 1:4, 1:2, 1:1, and 2:1) and amount of each sugar (from 2% to 20%). As a result, a ratio of 2:1 (sucrose to maltose, 10:5% or 20:10%, w/v) was determined as an optimal condition for long-chain IMO synthesis (DP3-DP9) with relatively higher yields (70-90%, respectively).

Monitoring of Leuconostoc mesenteroides DRC starter in fermented vegetable by random integration of chloramphenicol acetyltransferase gene.

In 2004, Leuconostoc mesenteroides DRC was first used as a starter culture for achieving higher organoleptic effects in Korean kimchi manufacture. For a better understanding of starter growth in a mixed culture system, and for predicting starter predominance in kimchi, a monitoring system for the starter was established. The chloramphenicol resistance marker gene (cat) was randomly integrated into chromosomal DNA of L.

Synbiotic synthesis of oligosaccharides during milk fermentation by addition of leuconostoc starter and sugars.

Synthesis of oligosaccharides during milk fermentation was attempted by inoculating Leuconostoc citreum with Lactobacillus casei, Lb. delbrueckii subsp. bulgaricus, and Streptococcus thermophilus as starters.

Selection of psychrotrophic Leuconostoc spp. producing highly active dextransucrase from lactate fermented vegetables.

Leuconostoc is the major bacterial genus in the initial phase of the lactate fermentation of vegetables. The dextransucrase elaborated from this bacterium is used to synthesize dextran polymers or prebiotic oligosaccharides. To use Leuconostoc as a starter culture in the manufacture of the kimchi-like fermented foods at low temperature, we isolated microbial flora that showed fast growth rates and high enzyme activity under the test conditions.