• Journal of Life Science
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• v.21 no.10
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• pp.1428-1433
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• 2011

In this study, we isolated and characterized plant-associated lactic acid bacteria which are able to produce angiotensin-converting enzyme (ACE) inhibitory and antioxidative activities. Five lactic acid bacteria were isolated from plants (grape and leek), a plant-associated fermentative product (Kimchi) and Korean traditional alcohol (Dongdongju). Strains K-1 and K-21 from Kimchi, strain L-5 from leek, strain G-3 from grape, and strain D-3 from Dongdongju were identified as Pediococcus pentosaceus, Lactobacillus plantarum, Weissella cibaria, L. plantarum, and L. brevis, respectively, by 16S rRNA gene analysis. ACE inhibitory activities of isolated strains ranged from 44.3 to 71.9% in the MRS broth. G-3, L-5 and K-1 strains especially showed high ACE inhibitory activities (59.8-98.69%) in the MRS broth containing skim milk. DPPH radical scavenging activities of the strains were in the range of 42.5-82.7%. All strains showed varying levels of resistance in artificial gastric fluid (pH 2.5), retaining viability ranging from 42.2 to 88.1% after 3 hr of incubation. All strains showed high resistance to 0.3% oxgall after 24 hr of incubation; survival rates were in the range of 55.4-112.8%. Isolated strains were found to be antagonistic to some pathogens including Pseudomonas aeruginosa.

• Journal of Microbiology and Biotechnology
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• v.29 no.4
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• pp.558-561
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• 2019

This study aimed to understand the survival and growth patterns of bacteriophage-sensitive Weissella and Leuconostoc strains involved in kimchi fermentation. Dongchimi kimchi was prepared, and Weissella and Leuconostoc were co-cultivated in the dongchimi broth. Weissella cibaria KCTC 3807 growth was accompanied by rapid lysis with an increase in the bacteriophage quantity. Leuconostoc citreum KCCM 12030 followed the same pattern. The bacteriophage-insensitive strains W. cibaria KCTC 3499 and Leuconostoc mesenteroides KCCM 11325 survived longer under low pH as their growth was not accompanied by bacteriophages. The bacteriophage lysate of W. cibaria KCTC 3807 accelerated and promoted the growth of Leuconostoc. Overall, our results show that bacteriophages might affect the viability and population dynamics of lactic acid bacteria during kimchi fermentation.

• Microbiology and Biotechnology Letters
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• v.5 no.4
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• pp.171-175
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• 1977

A microbial strain capable of producing lactic acid was isolated and identified as Streptococcus faecium. During the incubation of the isolated bacterium in a synthetic medium (Petterson broth), the optimal temperature was 36 to 39$^{\circ}C$ and the cell concentration at stationary growth phase was 2.1${\times}$10$\^$8/ viable cells/ml. When it was dried in vacuum and diluted with avicel, the Viability of Streptococcus faecium in physiological saline solution was decreased to 80％ after incubation for 48 hr at 37$^{\circ}C$, whereas the viability was above 90％ after incubation for 1 hr at 40$^{\circ}C$ and the viability in M buffer solution (pH 4.5∼9.0) at 37$^{\circ}C$ was above 95％. From these data it was concluded that the isolated microbe must be adoptible for pharmaceutical preparation such as solid dosage form.

• Korean Journal of Food Science and Technology
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• v.30 no.3
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• pp.660-664
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• 1998

Death of non-growing microorganisms in saline was studied to observe the inhibitory effect of NaCl in foods on the viability of microorganisms. When Leuconostoc mesenteroides LA10, Staphylococcus aureus B31 and Escherichia coli B34 were incubated in McIlvaine buffer with 0, 10, 20, 30% NaCl at $30^{\circ}C$, they survived best at pH 6, 5, 7, respectively. The survival of 5 lactic acid bacteria, 9 other bacteria and 2 yeasts was tested at pH 5, 6, 7 with 10% NaCl. Gram-positive bacteria survived in saline better than Gram-negative bacteria, and lactic acid bacteria and S. aureus survived better than other bacteria. The number of survivors decreased as concentrations of NaCl increased and as pH moved to acidic or alkaline side from the above-mentioned. When L. mesenteroides LA10 was incubated in saline with those materials which are known to protect microorganisms from the killing effect of NaCl, protective effect was not observed.

• Food Engineering Progress
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• v.14 no.3
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• pp.208-216
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• 2010

Lab scale experiments were conducted in order to assess the applicability of $CaCO_{3}$-alginate beads as neutralizer for the high cell density cultivation and prepare the direct vat inoculation cultures of isolated sourdough lactic acid bacteria. With increasing the amount of bead and decreasing the diameter of bead in acidic solution, the neutralizing effect of $CaCO_{3}$-alginate bead became higher. In batch process with $CaCO_{3}$-alginate beads, Lactobacillus amylovorus DU-21 isolated from sourdough showed the highest viable cell counts and optical density in MRS broth. The values of viable cell counts and optical density were 9.996 log CFU/mL and 3.97, respectively. Experiments on the conditions which increase viability during lyophilization were carried out and the following results were obtained; 15% glycerol revealed the high cryoprotective effect on the concentrated cultures during lyophilization among the two cryoprotective agents. Consequently, $CaCO_{3}$-alginate beads and 15% glycerol were found to be useful not only to cultivate Lactobacillus amylovorus DU-21 but also to preserve strain.

• Microbiology and Biotechnology Letters
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• v.41 no.2
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• pp.190-197
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• 2013

Three slime-forming lactic acid bacteria were isolated from traditional Korean fermented soy sauce and soybean paste and shown to produce exopolysaccharides (EPS) in sucrose media. By isolating the strains, examining their morphological characteristics and determining their 16S rDNA sequences, N58-5 and K6-7 were identified as Leuconostoc mesenteroides and N45- 10 as Leuconostoc citreum. The acid and bile tolerances of these three strains were investigated. Amongst the three lactic acid bacteria, Leuc. citreum N45-10 exhibited the highest viability ($10^5-10^6$ CFU/ml) in 0.05 M sodium phosphate buffer (pH 0.3) for 2 h, in artificial gastric juice for 2 h and in 0.3%, 0.5% oxgall for 24h. Leuc. mesenteroides K6-7, N58-5 and Leuc. citreum N45- 10 were grown in sucrose liquid medium and 8.16 g/L, 3.65 g/L, 16.17 g/L of EPS was collected, respectively. The hydrolyzed EPS was analyzed by HPLC in order to determine the sugar composition of EPS. Leuc. mesenteroides K6-7 and N58-5 showed two peaks indicating glucose and fructose, thus they were determined to be hetero-type polysaccharides. Leuc. citreum N45-10 showed only the glucose polymer, indicating it to be a homo-type polysaccharide. In addition, all three lactic acid bacterial hemolysis did not demonstrate a clear zone in blood agar in the area surrounding a lactic acid bacteria colony.

• Food Science of Animal Resources
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• v.40 no.2
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• pp.297-310
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• 2020

This study aims to evaluate the probiotic properties of Lactobacillus brevis (L. brevis) KU200019 and the synergistic activity with prebiotics on antimicrobial activity, and the potential application as an adjunct culture in fermented dairy products. The commercial strain, L. brevis ATCC 14869 was used as reference strain. L. brevis KU200019 was showed higher viability in simulated gastric (99.38±0.21%) and bile (115.10±0.13%) conditions compared to reference strain. L. brevis KU200019 exhibited antimicrobial activity against various foodborne pathogens. The supplementation of fructooligosaccharides (FOS) enhanced viability of lactic acid bacteria (>8 Log CFU/mL) and antioxidant activity [2,2-diphenyl-2-picrylhydrazyl radical assay (DPPH) assay, 31.23±1.14%; 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assay, 38.82±1.46%] in fermented skim milk during refrigerated storage. L. brevis KU200019 was distinguished from the reference strain by its higher probiotic potential, antimicrobial activity, and higher antioxidant activity in fermented milk. Therefore, L. brevis KU200019 with FOS was demonstrated promising properties for further application in fermented dairy products with enhanced safety and quality.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.127-127
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• 2018

Probiotics are microorganisms that have beneficial effects on the health of the host. The health promoting effect by probiotics influences suppressing harmful bacteria, prevention of constipation, blood cholesterol reduction and regulation of blood pressure. Prebiotics are used to promote the growth or activity of microorganisms. Synbiotics, which are a mixture of probiotics and prebiotics, synergize in the intestines by complementing each other. Synbiotics not only improves the viability of the probiotics while passing through the gastrointestinal tract, maintain intestinal homeostasis, but also regulate balance of harmful and useful bacterial growth. Glycine max Merr (GMM) has been widely used in Asian countries to treat cancer, obesity, oxidative stress and imbalanced immune diseases. In addition, it has been reported that dietary fiber-rich grains promote bowel movements and prevent constipation. In this study, we investigated the viability of LactobacillIus buchneri (L.buchneri) strains, known as lactic acid bacteria under conditions of gastric fluid and intestinal fluid to determine the suitability of L.buchneri as probiotics. The adhesion ability of L.buchneri to caco-2 cells was also confirmed. The present studies showed that GMM extract promoted the growth and activity of L.buchneri strains as prebiotics. Also, this results suggested that the mixture of L.buchneri and GMM extract can helps maintain intestinal health and healthy body as synbiotics and health functional food material.

• Journal of Pharmaceutical Investigation
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• v.30 no.1
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• pp.47-50
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• 2000

A new technique has been developed for the preparation of Lactobacillus microcapsules to enhance the stability against high temperature, humidity, gastric acid and bile acid. Employing fluidized bed coating, primary sub-coating was processed in non-organic solvent system, so that Lactobacillus did not directly contact with organic solvent. Secondary enteric-coating was processed in organic solvent with low temperature $(below\;33^{\circ}C)$ technique, which minimized the heat labilability of Lactobacillus. Survival rate of Lactobacillus within microcapsule was not less than 95% and acid tolerance was above 30% in the artificial gastric acid. Further more it was dissolved in the artificial intestine juice within 2-3 hr. Average size of Lactobacillus microcapsules was $450\;{\mu}m$(25-50 mesh) and its viability was above 90% in the direct tableting.

• Microbiology and Biotechnology Letters
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• v.51 no.2
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• pp.191-202
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• 2023

Elevated serum cholesterol is a main risk factor for heart disorders. Most probiotic products administered to lower cholesterol are dairy products which are not suitable for lactose-intolerant individuals. In this study, we assessed the cholesterol-lowering efficacy of LAB isolated from traditionally fermented drinks in diet-induced rats and determine their efficacy in the production of non-dairy, probiotic formulations using papaya juice. LAB were isolated from palm wine and corn beer on MRS agar using a pour-plate technique. Identification was carried out using 16S rRNA gene sequencing. A hypercholesterolemia model in which diet-induced Wistar albino rats were assigned into four groups was established. Oral gavage was carried out for 30 days. On the 31^st day, the rats were dissected and the serum lipid profile was analyzed using biochemical kits. A 10⁶ cfu/ml of a 24-h-old culture of selected lactobacilli was used to inoculate papaya juice and incubated at 37℃. Microbial and chemical changes were assessed during papaya fermentation and after four weeks of cold storage. Two selected isolates (Pw1 and Cb4) had in vitro cholesterol reduction of > 80%. These two isolates lowered lipid profile (triglyceride, total cholesterol, LDL-c) significantly, and increased HDL-c levels (p < 0.5) in the rat sera. Phylogenetic analysis showed that Pw1 was 98.86% similar to Limosilactobacillus fermentum, while Cb4 was 99.54% similar to Enteroccocus faecium. Both strains fermented papaya juice with cell viability reaching 8.92 × 10⁸ cfu/ml and 25.3 × 10⁸ cfu/ml respectively, and were still viable after 4 weeks of cold storage.