• Journal of Microbiology and Biotechnology
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• v.34 no.9
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• pp.1803-1809
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• 2024

Leuconostoc lactis DMLL10 is a microorganism specific to kimchi fermentation. In this study, we sought to evaluate the toxicity of this strain, which was newly isolated from kimchi, to determine its safety as a food ingredient. Bacterial reverse mutation assay, chromosomal aberration assay, and mammalian cell in vitro micronucleus assay were performed to assess the genetic toxicity of Leu. lactis DMLL10. The strain did not induce mutagenicity in Salmonella typhimurium TA98, TA100, TA1535, TA1537, or Escherichia coli WP2uvrA, with or without metabolic activation of S9 mixture. The oral administration of Leu. lactis DMLL10 also did not significantly increase the number of micronucleated polychromatic erythrocytes, or the mean ratio of polychromatic to total erythrocytes. Additionally, Leu. lactis DMLL10 did not cause a significant chromosomal aberration in CHU/IL cells in the presence or absence of S9 activation. Therefore, Leu. lactis DMLL10 can be suggested as a functional food ingredient with reliability and safety.

• Food Engineering Progress
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• v.21 no.4
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• pp.383-390
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• 2017

Glucansucrase is an enzyme classified as a glycoside hydrolase (GH) 70 family, which catalyzes the synthesis of glucooligosaccharides with a low molecular weight using sucrose as a donor of D-glucopyranose and maltose as a carbohydrate acceptor. In this study, glucansucrase-producing lactic acid bacteria strain was isolated from the fermented foods collected in traditional markets, and the optimum conditions for the oligosaccharide production were investigated. The strain CCK940 isolated from Chinese cabbage kimchi was selected as an oligosaccharide-producing strain due to its high glucansucrase activity, with 918.2 mU/mL, and identified as Leuconostoc lactis. The optimum conditions for the production of oligosaccharides using Leu. lactis CCK940 were to adjust the initial pH to 6.0, add 5% (w/v) sucrose and 10% (w/v) maltose as a donor and acceptor molecules, respectively, and feed 5% (w/v) sucrose at 4 and 8 h of cultivation. When Leu. lactis CCK940 was cultured for 12 h at optimum conditions, at least four oligosaccharides with a polymerization degree of 2-4 were produced.

• Korean Journal of Food Science and Technology
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• v.43 no.2
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• pp.169-175
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• 2011

The ${\beta}$-xylosidase (EC 3.2.1.37) production capabilities of lactic acid bacteria in the genus Leuconostoc, isolated from a variety of kimchi (fermented vegetables), were examined. The intracellular levels of ${\beta}$-xylosidase were similar to the extracellular levels, when most Leuconostoc lactic acid bacteria were grown in a medium containing xylose as the carbon source. Intracellular ${\beta}$-xylosidase with a maximum activity of $1.2{\pm}0.1units/mL$ (mean${\pm}$standard error) was obtained from Leuconostoc lactis KCTC 13344, which was isolated from fermented Chinese cabbage. The optimum reaction conditions for Leu. lactis KCTC 13344 ${\beta}$-xylosidase activity were pH 6.0 and $30^{\circ}C$, and the addition of most divalent cations, except zinc, to the reaction mixture resulted in a slight increase in enzyme activity. Compared with a media containing other carbon sources, the ${\beta}$-xylosidase activity was 5 times higher when Leu. lactis KCTC 13344 was grown in a medium containing xylose as carbon source. Zymographic analysis indicated that the synthesis of Leu. lactis KCTC 13344 ${\beta}$-xylosidase (approximate size, 64 kDa) is induced by xylose. A maximum intracellular ${\beta}$-xylosidase activity of $7.1{\pm}0.3units/mL$ was obtained in a batch cultivation in an MRS medium containing 30 g/L xylose.

• KSBB Journal
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• v.15 no.4
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• pp.359-365
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• 2000

Three lactic acid bacteria (C-1 K-3 and T-1 strain) were isolated from Nuruk and characterized subsequently. They were useful strains for production of lactic acid and their growth was inhibited at 10% ethanol pH 4 These strains were identified as lactococcus lactis subsp. lactis NR C-1 Leuconostoc mesenteroides subsp. mesenterides NR K-3 and pediococcus pentosaceus NR T-1 respectively by morphological physiological and biochemical characterization Lac lactis subsp lactis NR C-1 showed the highest lactic acid productivity. Leu measenteroides subsp mesenteroides NR K-3 showed stable lactic acid productivity and its growth was inhibited at pH 4. P pentosaceus NR T-1 had lower lactic acid productivity than the other two bacteria but it could not grow at 10% ethanol pH 4 The lactic acid productivity of these three strains in MRS broth were higher than that in Skim milk media the optimum pH and temperature for the lactic acid production of the three strains were 30-32$^{\circ}C$ and pH 6.0∼6.8 Glucose was the optimal carbon souorce for the lactic acid production. In terms of antagonism lac lactis subsp lactis NR c-1 showed somewhat inhibitory efects against some Gram positive rod and cocci such as Lactobacillus brevis and Streptococcus mitis. And Leu mesenteroides subsp mesenteroides NR K-3 showed the inhibitory effects against Streptococcus mitis but P. pentosaceus NR T-1 didn't show any inhibitory effects against tested strains.

• Journal of Microbiology and Biotechnology
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• v.32 no.3
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• pp.333-340
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• 2022

Leuconostoc has been used as a principal starter in natural kimchi fermentation, but limited research has been conducted on its phages. In this study, prophage distribution and characterization in kimchi-derived Leuconostoc strains were investigated, and phage induction was performed. Except for one strain, 16 Leuconostoc strains had at least one prophage region with questionable and incomplete regions, which comprised 0.5-6.0% of the bacterial genome. Based on major capsid protein analysis, ten intact prophages and an induced incomplete prophage of Leu. lactis CBA3626 belonged to the Siphoviridae family and were similar to Lc-Nu-like, sha1-like, phiMH1-like, and TPA_asm groups. Bacterial immunology genes, such as superinfection exclusion proteins and methylase, were found on several prophages. One prophage of Leu. lactis CBA3626 was induced using mitomycin C and was confirmed as belonging to the Siphoviridae family. Homology of the induced prophage with 21 reported prophages was not high (< 4%), and 47% identity was confirmed only with TPA_asm from Siphoviridae sp. isolate ct3pk4. Therefore, it is suggested that Leuconostoc from kimchi had diverse prophages with less than 6% genome proportion and some immunological genes. Interestingly, the induced prophage was very different from the reported prophages of other Leuconostoc species.

• Journal of Microbiology and Biotechnology
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• v.31 no.2
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• pp.298-303
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• 2021

Comparative genomic analysis was performed on eight species of lactic acid bacteria (LAB)-Lactococcus (L.) lactis, Lactobacillus (Lb.) plantarum, Lb. casei, Lb. brevis, Leuconostoc (Leu.) mesenteroides, Lb. fermentum, Lb. buchneri, and Lb. curvatus-to assess their glutamic acid production pathways. Glutamic acid is important for umami taste in foods. The only genes for glutamic acid production identified in the eight LAB were for conversion from glutamine in L. lactis and Leu. mesenteroides, and from glucose via citrate in L. lactis. Thus, L. lactis was considered to be potentially the best of the species for glutamic acid production. By biochemical analyses, L. lactis HY7803 was selected for glutamic acid production from among 17 L. lactis strains. Strain HY7803 produced 83.16 pmol/μl glutamic acid from glucose, and exogenous supplementation of citrate increased this to 108.42 pmol/μl. Including glutamic acid, strain HY7803 produced more of 10 free amino acids than L. lactis reference strains IL1403 and ATCC 7962 in the presence of exogenous citrate. The differences in the amino acid profiles of the strains were illuminated by principal component analysis. Our results indicate that L. lactis HY7803 may be a good starter strain for glutamic acid production.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.399-404
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• 2002

The fermented fruit and vegetable mixed broth was prepared by using bacteriocin-producing lactic acid bacteria to evaluate the possibility of developing isotonic beverage with anticariogenic activity. Optimum conditions were also established to produce bacteriocin by a mixed culture system consisting of Lc. lactis and Leu. mesenteroides in a fruit and vegetable mixture. Production of bacteriocin was not observed when both strains were simultaneously innoculated, but pH adjustment of the broth fermented by Leu. mesenteroides to nearneutral pH stimulated the production of bacteriocin by Lc. lactis. The concentration of sodium of the fermented broth was higher than those of commercial products. Color change of the fermented broth was not observed during storage. The fermented broth showed strong inhibitory effect against Streptococcus mutans which is an oral inhabitant with a cariogenic activity. Bacteriocin activity in the fermented broth was retained very stable for 4 weeks at 4$\^{C}$. The results indicated that bacteriocin-producing lactic acid bacteria can be used for the preparation of a Korean style thirst-quenching beverage containing bacteriocin.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.506-515
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• 1995

The cultural characteristics of 60 strains of psychrotrophic lactic acid bacteria which were isolated from kimchi, a Korean traditional fermented vegetable food, and identified as Leuconostoc mesenteroides subsp. mesenteroides, Leu. mesenteroides subsp. dextranicum, Leu. paramesenteroides, Leu. lactis, Lactobacillus bavaricus and Lac. homohiochii were tested. All strains grew at $5^{\circ}C,\;10^{\circ}C\;and\;37^{\circ}C$ in tomato glucose broth, but not at $45^{\circ}C$. The optimum growth temperature of Leu. mesenteroides and Lactobacillus sp. were $33{\sim}34^{\circ}C\;and\;34{\sim}36^{\circ}C$, respectively. All strains of Leu. mesenteroides and Lactobacillus sp. grew at 4.8 and 4.2 of initial pH, but not at 4.0. The final pH of Leu. mesenteroides and Lactobacillus sp. in glucose broth were $3.84{\sim}4.10\;and\;3.82{\sim}3.99$, respectively. None of the 60 strains clotted milk nor reduced litmus in litmus milk. All strains of Leu. mesenteroides and Lactobacillus sp. grew in tomato glucose broth containing 7% ethanol or 6.5% NaCl, but not in the broth containing 15% ethanol or 10% NaCl. All strains grew in tomato glucose broth containing 40% bile juice and survived in the artificial gastric juice of pH 3.5. Furthermore, all strains of Leu. mesenteroides survived in the artificial gastric juice of pH 3.0. Since many strains of lactic acid bacteria tested in this study showed differences in several physiological characteristics from those described in Bergey's Manual of Systematic Bacteriology, it was considered that further tests would be necessary to clarify their positions in taxonomic system.

• Journal of Microbiology and Biotechnology
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• v.17 no.9
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• pp.1521-1526
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• 2007

A maltogenic amylase gene from Lactobacillus gasseri ATCC33323 (LGMA) was expressed in Lactococcus lactis MG1363 using the P170 expression system. The successful production of recombinant LGMA (rLGMA) was confirmed by the catalytic activity of the enzyme in liquid and solid media. The N-terminal amino acid sequencing analysis of the rLGMA showed that it was Met-Gln-Leu-Ala-Ala-Leu-, which was the same as that of genuine protein, meaning the signal peptide was efficiently cleaved during secretion to the extracellular milieu. The optimal reaction temperature and pH of rLGMA ($55^{\circ}C$ and pH 5, respectively) and enzymatic hydrolysis patterns on various substrates (${\beta}$-cyclodextrin, starch, and pullulan) supported that rLGMA was not only efficiently secreted from the Lactococcus lactis MG1363 but was also functionally active. Finally, the branched maltooligosaccharides were effectively produced from liquefied com starch, by using rLGMA secreted from Lactococcus lactis, with a yield of 53.1%.

• Preventive Nutrition and Food Science
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• v.16 no.4
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• pp.386-389
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• 2011

Previous studies have confirmed that fermented whey produced by Leuconostoc mesenteroides CJNU 0147 or Lactobacillus casei CJNU 0588 display bifidogenic growth stimulator (BGS) activity. The present study sought to determine if the strain itself can improve the growth of bifidobacteria in co-cultures. In reinforced clostridial medium (RCM), both strains stimulated the growth of a Bifidobacterium lactis strain during the exponential phase and also stimulated the growth during almost all growth phases in whey broth. Fermented whey containing viable Leu. mesenteroides CJNU 0147 and L. casei CJNU 0588 cells maintained viability of the B. lactis strain stored at $10^{\circ}C$ in MRS broth. Viable cell count of the B. lactis strain without the fermented whey was decreased to 5.6 log cfu/mL after 15 days, whereas that of the strain with the fermented whey was slightly increased to 7.1 log cfu/mL as compared with initial viable cell count of 6.9 log cfu/mL.