• Journal of Life Science
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• v.12 no.6
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• pp.812-820
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• 2002

In order to understand stress response of Leuconostoc mesenteroides against lactic acid, a new Leuconostoc sp. which has acid tolerance was isolated from various Kimchi samples. And it identified as Leuconostoc mesenteroides LM3 by comparing its fatty acid composition with reference strain. Its growth pattern was investigated by adding a given concentration of lactic acid at the lag phase to the stationary phase. In the DeMan, Rogosa, Sharpe (MRS) media containing over 0.4% (final v/v) lactic acid, this strain slowed slowly After exposure of the stationary phase cells to 4% of lactic acid for 60 min, this strain could survive, whereas a reference strain, Leuconostoc mesenteroides KCTC3505, showed no survival. And changes of trehalose concentration, the activity of trehalase and ATPase in the growth of Leuconostoc mesenteroides LM3 after addition of 0.6% (final v/v) lactic acid were investigated : After exposure to lartic acid, trehalose concentration in this strain was increased in comparison with no treatment, but its trehalase activity was not changed. And its ATPase activity was constant, and intracellular pH was almost constant. This result meant Leuconostoc mesenteroides LM3 should have a tolerance against lactic acid. It remains to further study the mechanism of this acid tolerance.

• Journal of Microbiology and Biotechnology
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• v.23 no.6
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• pp.837-842
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• 2013

A cryptic plasmid, pMBLR00, from Leuconostoc mesenteroides subsp. mesenteroides KCTC 3733 was isolated, characterized, and used for the construction of a cloning vector to engineer Leuconostoc species. pMBLR00 is a rolling circle replication plasmid, containing 3,370 base pairs. Sequence analysis revealed that pMBLR00 has 3 open reading frames: Cop (copy number control protein), Rep (replication protein), and Mob (mobilization protein). pMBLR00 replicates by rolling circle replication, which was confirmed by the presence of a conserved double-stranded origin and single-stranded DNA intermediates. An Escherichia coli-Leuconostoc shuttle vector, pMBLR02, was constructed and was able to replicate in Leuconostoc citreum 95. pMBLR02 could be a useful genetic tool for metabolic engineering and the genetic study of Leuconostoc species.

• Journal of Microbiology
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• v.45 no.4
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• pp.291-296
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• 2007

Insoluble glucans synthesized by Streptococcus mutans enhance the pathogenicity of oral biofilm by promoting the adherence and accumulation of cariogenic bacteria on the surface of the tooth. The objective of this study was to investigate the effect of Leuconostoc spp. on the in vitro formation of S. mutans biofilm. Three strains, Leuconostoc gelidum A TCC 49366, Leuconostoc mesenteroides ssp. cremoris A TCC 19254 and Leuconostoc mesenteroides ssp. mesenteroides ATCC 8293, were used in this study. They exhibited profound inhibitory effects on the formation of S. mutans biofilm and on the proliferation of S. mutans. The water-soluble polymers produced from sucrose were most strongly produced by L. gelidum, followed by L. mesenteroides ssp. cremoris and L. mesenteroides ssp. mesenteroides. The mean wet weights of the artificial biofilm of S. mutans were also significantly reduced as a result of the addition of the water-soluble polymers obtained from Leuconostoc cultures. According to the results of thin-layer chromatographic analysis, the hydrolysates of the water-soluble polymers produced by Leuconostoc were identical to those of dextran T-2000, forming predominately ${\alpha}-(1-6)$ glucose linkages. These results indicate that dextran-producing Leuconostoc strains are able to inhibit the formation of S. mutans biofilm in vitro.

• KSBB Journal
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• v.28 no.3
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• pp.213-215
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• 2013

A high-throughput screening strategy was developed to simplify the selection process for improved mannitol producing strain after chemical mutagenesis. Ethylmethyl sulfonate (EMS) was used as a chemical mutagen to alter the fructokinase-I gene which is an essential enzyme to metabolize fructose for growth. Leuconostoc mesenteroides treated with EMS were plated on the modified MRS solid medium containing fructose as a sole carbon source. Strains showing inhibited growth were primarily selected to evaluate the mannitol producing ability. By applying this strategy, L. mesenteroides ATCC 8293 M1, L. mesenteroides ATCC 9135 M3 and L. mesenteroides D1 M3 showed improvement in mannitol production.

• Applied Biological Chemistry
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• v.51 no.1
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• pp.88-91
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• 2008

숙성 중인 김치에서 생육과 산 생성이 우수한 유산균을 분리하여 API 50 CHL kit로 확인하고 16S rDNA의 염기 서열을 분석한 결과 Leuconostoc mesenteroides로 동정되어 Leuconostoc mesenteroides KC51로 명명하였다. 대두에 10배의 증류수를 가하여 제조한 두유에 KC51 균주를 접종하고 $30^{\circ}C$에서 정치 배양한 결과, 생균수는 접종 후 9시간까지 급격히 증가하였으며 그 이후 완만하게 증가하여 배양 12시간에는 $2.70{\times}10^9$ CFU/g까지 증가하였다. 적정산도는 배양 12시간에 0.35%까지 증가하였으며,pH 는 pH 4.52까지 감소하였다. 이때 유기산 농도는 젖산과 초산의 함량이 각각 0.56%와 0.10%로 분석 되었다. 두유 발효액에서 Leuconostoc mesenteroides의 증식에 의한 점도의 증가는 관찰되지 않았으며, 관능적으로도 신맛을 제외한 항목에서 두유와 유사하였다. 또한 $4^{\circ}C$에서 두유 발효액은 2주일의 저장기간 동안 pH, 적정산도와 생균수의 변화는 미미하였다.

• Microbiology and Biotechnology Letters
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• v.27 no.1
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• pp.35-40
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• 1999

Alternan known as a kind of dextran is a linear and cyclic polysaccharide which is synthesized with sucrose by alternaansucrase (EC2.4.1.140) of Leuconostoc mesenteroides. But this polysaccharide is different from dextran in its structure and other properties. For the purpose of applying alternan for the food, cosmetic, and pharmaceutical industries, we isolated an excellent alternan-porducing strain, Leu. mesenteroides CBI-110. The optimum culture conditions were studied to improve the yield, and the activity of alternansucrase was increased up to 33U/ml in the optimum culture media. The concentrations of $Mn^{2+}$ and $Cu^{2+}$ ions were 0.01% and 0.03%, respectively, for the effective production of alternan. Finally, we obtained 25.6g/L of alternan.

• Korean Journal of Food Science and Technology
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• v.27 no.4
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• pp.495-505
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• 1995

The purpose of this study was to identify the psychrotrophic lactic acid bacteria isolated from kimchi, a Korean traditional fermented vegetable food. Thirty isolates of psychrotrophic lactic acid bacteria were isolated randomly from kimchi-A and kimchi-B which were fermented at $5{\sim}7^{\circ}C$ for 20 days and 50 days, respectively. Among 30 isolates of lactic acid bacteria isolated from kimchi-A, 14 isolates were identified as Leuconostoc mesenteroides subsp. mesenteroides, 12 as Leuconostoc mesenteroides subsp. dextranicum and 4 as Lactobacillus bavaricus. Among 30 isolates isolated from kimchi-B, 20 isolates were identified as Lactobacillus bavaricus, 3 as Leuconostoc mesenteroides subsp. mesenteroides, 3 as Leuconostoc lactis, 2 as Leuconostoc paramesenteroides and 2 as Lactobacillus homohiochii. Though these strains were identified as above, there were many strains whose sugar fermenting patterns and $NH_3$ producing ability from arginine were inconsistent with those described in Bergey's Manual of Systematic Bacteriology, and some strains identified as Leuconostoc mesenteroides subsp. mesenteroides and Leuconostoc mesenteroides subsp. dextranicum even disclosed such contradictions as the comparisons of sugar fermenting patterns between the strains of different subspecies were much more coincident than those between the same subspecies. As there were difficulties in classifying these psychrotrophic lactic acid bacteria according to the current taxonomic system, further studies were needed to solve these problems.

• Microbiology and Biotechnology Letters
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• v.34 no.3
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• pp.196-203
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• 2006

Three slime-forming lactic acid bacteria were isolated from Kimchi and shown to produce viscous exopolysaccharides (EPS) in sucrose media. The isolated strains, GJ2, C3 and C11, were identified as Leuconostoc kimchii, Leuconostoc citreum and Leuconostoc mesenteroides, respectively, by examining their metabolic characteristics and determining their 16S rDNA sequences. Leu. kimchii GJ2, Leu. citreum C3 and Leu. mesenteroides C11 exhibited high viability (maintained initial viable cell count of $10^8$ CFU/ml) in 0.05 M sodium phosphate buffer (pH 3.0) for 2 h, in artificial gastric juice for 2 h and in 0.3% oxgall for 24 h. When tested, Leu. kimchii GJ2, in particular, displayed antimicrobial activity against pathogenic microorganisms. Leu. kimchii GJ2, Leu. citreum C3 and Leu. mesenteroides C11 produced 21.49 g/l, 16.46 g/l and 22.98 g/l EPS, respectively, in sucrose (5%) medium. The amount of purified EPS extracted from Leu. kimchii GJ2, Leu. citreum C3 and Leu. mesenteroides C11 was 14.61 g/l, 7.73 g/l and 4.77 g/l, respectively. Although the EPS produced by Leu. kimchii GJ2, Leu. citreum C3 and Leu. mesenteroides C11 differed in viscosity, TLC and HPLC analysis revealed that each contained only one type of monosaccharide, glucose. The average molecular mass of EPS produced by Leu. kimchii GJ2 was 306,606 Da.

• Korean Journal of Microbiology
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• v.27 no.4
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• pp.404-414
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• 1989

Attempts were made to isolate and identify Gram-positive or lactic acid bacteria in Kimchi fermentation. Species diversity depended on isolation media and temperatures, and diversity tended to be reduced with decrease of temperature. MRS and KM (natural medium prepared from Kimchi materials) were suitable respectively for isolation and present number of species. Identification of isolates was performed by dichotomous identification schemes arranged on the basis of Bergey's manual of Systematic Bacteriology (1986). Gram-positive bacteria isolated at different temperatures (5, 15, $25^{\circ}C$) were 5 species of Leuconostoc, 4 species of Streptococcus, 3 species of Pediococcus, 2 species of Bacillus and 18 species of Lactobacillus. Species with high frequency of appearance were Lactobacillus plantarum, Streptococcus raffinolactis, Leuconostoc mesenteroides subsp. mesenteroides at $25^{\circ}C$, L. plantarum, Lactobacillus fructosus, L. mesenteroides subsp. mesenteroides at $15^{\circ}C$ and L. mesenteroides subsp. mesenteroides, Leuconosotoc paramesenteroides, Lactobacillus maltaromicus at $15^{\circ}C$. In general, Kimchi fermentation was achieved by Lactobacillus spp. (59.7% frequency) at $25^{\circ}C$ and Leuconostoc spp. (65.2% frequency) at $5^{\circ}C$. Pediococcus cerevisiae and Streptococcus faecalis which have been so far known as bacteria of Kimchi fermentation were not isolated.

• Journal of Microbiology and Biotechnology
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• v.11 no.4
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• pp.700-703
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• 2001

The influence of process conditions on highly branched glucooligosaccharides production by mixed culture of Leuconostoc mesenteroides ATCC 13146 and Lipomyces starkeyi ATCC 74054 was studied. We divided the batch culture fermentations into two groups according to inoculation method. One-point inoculation was performed by coinoculation of L. mesenteroides and L. starkeyi at the ration of 10 to 1, and two-point inoculation by L. mesenteroides inoculation first and L. starkeyi inoculation after L. mesenteroides grew to the end of the log phase of growth. Two-point inoculation improved the yield of oligosaccharide by 1.5 to 20 fold more than one-point inoculation. In this process, the highest yield of oligosaccharides (48% of theoretical yield) and productivity (0.85 g/l/h) were obtained with starch as an initial substrate for L. starkeyi growth. The estimated composition of the end product consisted of 31.5% oligosaccharides, 17.6% dextran, and 46.5% mannitol.