• Journal of Microbiology and Biotechnology
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• 제33권12호
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• pp.1625-1634
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• 2023

Leuconostoc lactis strain DMLL10 was isolated from kimchi, a fermented vegetable, as a starter candidate through safety and technological assessments. Strain DMLL10 was susceptible to ampicillin, chloramphenicol, clindamycin, erythromycin, gentamicin, kanamycin, streptomycin, and tetracycline. It did not show any hemolytic activity. Regarding its phenotypic results related to its safety properties, genomic analysis revealed that strain DMLL10 did not encode for any toxin genes such as hemolysin found in the same genus. It did not acquire antibiotic resistance genes either. Strain DMLL10 showed protease activity on agar containing NaCl up to 3%. The genome of DMLL10 encoded for protease genes and possessed genes associated with hetero- and homo-lactic fermentative pathways for lactate production. Finally, strain DMLL10 showed antibacterial activity against seven common foodborne pathogens, although bacteriocin genes were not identified from its genome. These results indicates that strain DMLL10 is a novel starter candidate with safety, enzyme activity, and bacteriocin activity. The complete genomic sequence of DMLL10 will contribute to our understanding of the genetic basis of probiotic properties and allow for assessment of the effectiveness of this strain as a starter or probiotic for use in the food industry.

• 고신대학교 의과대학 학술지
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• 제33권3호
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• pp.422-430
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• 2018

Leuconostoc species are Gram-positive coccobacilli and are used in dairy products and are intrinsically resistant to vancomycin. Leuconostoc infections are rare in humans, usually occurring in immune-compromised patients. We describe 6 patients with Leuconostoc bacteremia at Dong-A university hospital between 1990 and 2015. One isolate (L. lactis) was identified to species level using 16S rRNA gene sequencing analysis. All patients had underlying diseases and 5 patients underwent procedures that interrupted the normal integumentary defense. Four patients died within 30 days after being identified as carrying Leuconostoc species.

• Journal of Microbiology and Biotechnology
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• 제26권3호
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• pp.493-497
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• 2016

Glucosyl rubusosides were synthesized by two dextransucrases. LcDexT was obtained from Leuconosotoc citreum, that LlDexT was obtained from Leuconostoc lactis. LcDexT and LlDexT regioselectively transferred a glucosyl residue to the 13-O-glucosyl moiety of rubusoside with high yield of 59-66% as analyzed by TLC and HPLC. Evaluation of the sweetness of these glucosyl rubusosides showed that their quality of taste, in particular, was superior to that of rubusoside. These results indicate that transglucosylation at the 13-O-glucosyl moiety of rubusoside by different regioselective dextransucrases can be applicable for increasing its sweetness and quality of taste.

• 한국식품영양과학회지
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• 제38권6호
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• pp.732-741
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• 2009

본 연구에서는 시판 김치로부터 분리된 젖산균을 동정하였다. 제조 후 4일 동안 실온에서 배양된 배추김치에서 12주, 2일 동안 실온에서 배양한 총각김치에서 6주, 5일 동안 실온에서 배양한 깍두기에서 15주, 그리고 4일 동안 배양한 파김치에서 23주의 젖산균이 분리되었다. 배추김치에서 분리된 12주의 젖산균 중 8주는 Lactobacillus plantarum로, 1주는 Leuconostoc lactis로, 2주는 Lactobacillus casei subsp. pseudoplantarum으로, 그리고 1주는 Lactobacillus sake로 동정되었다. 총각김치에서 분리된 6주의 젖산균 중 3주는 Leuconostoc paramesenteroides로, 2주는 Leuconostoc mesenteroides subsp. mesenteroides로, 그리고 1주는 Lactobacillus plantarum로 동정되었다. 깍두기에서 분리된 15주 중 2주는 Leuconostoc lactis로, 3주는 Leuconostoc mesenteroides subsp. dextricum로, 4주는 Lactobacillus casei subsp. pseudoplantarum로, 그리고 4주는 Lactobacillus coryniformis subsp. torquens로 동정되었다. 파김치에서 분리된 23주 중 22주는 L. plantarum으로 그리고 1주는 Lactobacillus sake로 동정되었다. 이상의 결과로부터, 배추김치에서는 L. plantarum이, 총각김치에서는 L. paramesenteroides이, 깍두기에서는 L. casei subsp. pseudoplantarum과 L. coryniformis subsp. torquens이, 그리고 파김치에서는 L. plantarum이 가장 많이 동정되었다. 특히 파김치에서는 선발된 23주 중 1주를 제외하고는 모두 L. plantarum으로 동정되었다.

• 한국자원식물학회지
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• 제24권6호
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• pp.712-718
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• 2011

Ginseng (Panax ginseng) is frequently used in Asian countries as a traditional medicine. The major components of ginseng are ginsenosides. Among these, ginsenoside compound K has been reported to prevent the formation of malignancy and metastasis of cancer by blocking the formation of tumor and suppressing the invasion of cancer cells. In this study, ginsenoside $Rb_1$ was converted into compound K, via secreted ${\beta}$-glucosidase enzyme from the Leuconostoc lactis DC201 isolated, which was extracted from Kimchi. The strain DC201 was suspended and cultured in MRS broth at $37^{\circ}C$. Subsequently, the residue from the cultured broth supernatant was precipitated with EtOH and then dissolved in 20 mM sodium phosphate buffer (pH 6.0) to obtain an enzyme liquid. Meanwhile, the crude enzyme solution was mixed with ginsenoside $Rb_1$ at a ratio of 1:4 (v/v).The reaction was carried out at $30^{\circ}C$ and 190 rpm for 72 hours, and then analyzed by TLC and HPLC. The result showed that ginsenoside Rb1 was transformed into compound K after 72 hours post reaction.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 춘계학술발표대회
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• pp.558-561
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• 2000

Strain JW3 was isolated from commercial Swiss cheese products and identified as a bacteriocin producer. Lactococcus lactis JW3 showed a broad spectrum of activity against most of the non-pathogenic and pathogenic microorganisms tested by the modified deferred method. Lacticin JW3 also showed a relatively broad spectrum of activity against non-pathogenic and pathogenic microorganisms as assessed using the spot-on-lawn method. It demonstrated a typical bactericidal mode of inhibition against Leuconostoc mesenteroides KCCM 11324.

• 한국미생물·생명공학회지
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• 제39권2호
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• pp.175-181
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• 2011

Kimchi is a group of traditional fermented vegetable foods in Korea and known to be the product of a natural mixed-fermentation process carried out principally by lactic acid bacteria (LAB). According to microbial results based on conventional identification, Leuconostoc mesenteroides and Lactobacillus plantarum were considered to be responsible for the good taste and over-ripening of kimchi, respectively. However, with the application of phylogenetic identification, based on 16S ribosomal RNA gene similarities, a variety of Leuconostoc and Lactobacillus species not detected in the previous studies have been isolated, together with a species in the genus Weissella. Additionally, Lactobacillus sakei has been accepted as the most populous LAB in over-ripened kimchi. In this study, Leuconostoc and Weissella species inhibiting the growth of Lb. sakei were isolated from kimchi for future applications to do with kimchi fermentation. From 25 kimchi samples, 378 strains in the genera Leuconostoc and Weissella were isolated and 68 strains identified as Lc. mesenteroides, Lc. citreum, Lc. lactis, W. cibaria, W. confusa, and W. paramesenteroides exhibited growth inhibition against Lb. sakei. Most of the strains also had antagonistic activities against Lb. brevis, Lb. curvatus, Lb. paraplantarum, Lb. pentosus, and Lb. plantarum. Their antagonistic activities against Lb. sakei were more remarkable at lower temperatures of incubation.

• Asian-Australasian Journal of Animal Sciences
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• 제28권8호
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• pp.1123-1132
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• 2015

Winter wheat is a suitable crop to be ensiled for animal feed and China has the largest planting area of this crop in the world. During the ensiling process, lactic acid bacteria (LAB) play the most important role in the fermentation. We investigated the natural population of LAB in whole-crop wheat (WCW) and examined the quality of whole-crop wheat silage (WCWS) with and without LAB inoculants. Two Lactobacillus plantarum subsp. plantarum strains, Zhengzhou University 1 (ZZU 1) selected from corn and forage and grass 1 (FG 1) from a commercial inoculant, were used as additives. The silages inoculated with LAB strains (ZZU 1 and FG 1) were better preserved than the control, with lower pH values (3.5 and 3.6, respectively) (p<0.05) and higher contents of lactic acid (37.5 and 34.0 g/kg of fresh matter (FM), respectively) (p<0.05) than the control. Sixty LAB strains were isolated from fresh material and WCWS without any LAB inoculation. These LAB strains were divided into the following four genera and six species based on their phenotypic, biochemical and phylogenetic characteristics: Leuconostoc pseudomesenteroides, Leuconostoc citreum, Weissella cibaria, Lactococcus lactis subsp. lactis, Lactobacillus buchneri, and Lactobacillus plantarum subsp. plantarum. However, the prevalent LAB, which was predominantly heterofermentative (66.7%), consisted of Leuconostoc pseudomesenteroides, Leuconostoc citreum, Weissella cibaria, and Lactobacillus buchneri. This study revealed that most of isolated LAB strains from control WCWS were heterofermentative and could not grow well at low pH condition; the selective inoculants of Lactobacillus strains, especially ZZU 1, could improve WCWS quality significantly.

• Journal of Microbiology and Biotechnology
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• 제22권9호
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• pp.1224-1229
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• 2012

Puerarin (P), an isoflavone derived from kudzu roots, has strong biological activities, but its bioavailability is often limited by its low water solubility. To increase its solubility, P was glucosylated by three dextransucrases from Leuconostoc or Streptococcus species. Leuconostoc lactis EG001 dextransucrase exhibited the highest productivity of puerarin glucosides (P-Gs) among the three tested enzymes, and it primarily produced two P-Gs with a 53% yield. Their structures were identified as ${\alpha}$-$_D$-glucosyl-($1{\rightarrow}6$)-P (P-G) by using LC-MS or $^1H$- or $^{13}C$-NMR spectroscopies and ${\alpha}$-$_D$-isomaltosyl-($1{\rightarrow}6$)-P (P-IG2) by using specific enzymatic hydrolysis, and their solubilities were 15- and 202-fold higher than that of P, respectively. P-G and P-IG2 are easily applicable in the food and pharmaceutical industries as alternative functional materials.

• Journal of Microbiology and Biotechnology
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• 제31권2호
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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.