• Journal of Life Science
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• v.28 no.1
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• pp.68-77
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• 2018

The purpose of this study was to isolate the probiotic lactic acid bacteria, and verify the possibility of the final selection strain as probiotic material. For screening of biogenic amines non-producing microorganisms, 42 lactic acid bacteria were isolated from various berries, extract and vinegar grown in Sunchang. Isolates were investigated for various physiological activities such as extracellular enzyme, antimicrobial and antioxidant activities, and 5 isolates were firstly screened. SBB07 was finally selected by analyzing the biogenic amine, and named Lactobacillus brevis SBB07 by 16S rRNA sequencing analysis. Next, SBB07 was assayed for their survival ability when exposed to acidic and bile conditions as well as heat and antibiotic resistance. As a result, SBB07 showed more than 86% and 54% higher survival rate in acidic condition at pH 2.0 and bile resistance with 0.5% oxgall. In addition, SBB07 showed a survival rate of more than 113% in $60^{\circ}C$, and also confirmed that it has resistant to various antibiotics. As a result of confirming the possibility of prebiotics, SBB07 showed the best utilization of GOS as a prebiotic substrate, and utilization of FOS and inulin were also high. These results suggest that SBB07 have good potential for application as probiotic lactic acid bacteria.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.8
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• pp.975-982
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• 2007

The purpose of this study was to investigate repeated-dose toxicity in male and female rats orally administered with Pediococcus pentosaceus MD1, an anti-Helicobacter pyroli producing lactic acid bacteria isolated from kimchi. Sprague-Dawley rats were divided into 4 groups, 10 animals in each group. The test article was administered once daily by gavage to rats at dose levels of 0, 500, 1,000 and 2,000 mg/kg for 4 weeks. No test article-related deaths and clinical findings in both sexes of rats during the study period were resulted. In addition, no differences were found between control and treated groups in body weight changes, food intake consumption and water consumptions. Hematological parameters, serum biochemical analysis and any other findings did not also show any significant or dose-dependent alterations. There were no alterations in absolute and relative organ weights by the administration of Pediococcus pentosaceus MD1. These results suggest that no-observed-adverse-effect level (NOAEL) of Pediococcus pentosaceus MD1 is considered to be more than 2 g/kg in male and female rats.

• Korean Journal of Microbiology
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• v.42 no.3
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• pp.216-222
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• 2006

This study was carried out to select the lactic acid bacteria producing ${\beta}-galactosidase$ (lactase) and investigate the properties of the ${\beta}-galactosidase$. About 100 strains of lactic acid bacteria showing blue colony on the MRS agar medium containing X-gal were isolated from several kinds of Kimchi. Among them, 2 strains were selected as potential ${\beta}-galactosidase$ producers. The selected strains, ET-1 and LA-12, were identified as Lactobacillus fermentum and L. acidophilus, respectively by the analysis of 16S rDNA sequences. They showed relatively high ${\beta}-galactosidase$ activity and cellular viability. Their ${\beta}-galactosidase$ showed the highest activity at $55^{\circ}C$. And the optimum pHs of the enzymes produced by ET-1 and LA-12 were pH 5.5 and pH 7.0, respectively. They were also highly resistant to artificial gastric juice and bile. Two selected strains showed little change of viable cell number for 3 hr incubation in artificial gastric juice, and maintained the viable cell number at $10^8CFU/ml$ for 24 hr in 0.3% oxgall after incubation for 2 hours in artificial gastric juice. Based on these results, ET-1 and LA-12 are expected to be applied in dairy industry.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.2
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• pp.201-210
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• 2009

This study was undertaken to investigate the quality properties of yakchobugak as affected by lactic acid bacteria and waxy rice paste for improving palatability of yakchobugak of Agastache rugosa. Total sugar contents of lactic acid bacteria-fermenting waxy rice paste gelatinized at $90^{\circ}C$ were higher than that of $70^{\circ}C$. Reducing sugar contents were $2{\sim}5$ times higher in $70^{\circ}C$ waxy rice paste than in $90^{\circ}C$ waxy rice paste and increased as the fermentation progressed. Total acidity of waxy rice pastes gelatinized at $70^{\circ}C$ and fermented for 15 hours were $2.7{\sim}1.3$ times higher than at $90^{\circ}C$, and then Lactococcus lactis had the lowest total acidity during fermentation. Viscosity of fermented paste (VFP) were lower than those of raw paste. VFPs gelatinized at $90^{\circ}C$ were markedly higher than those at $70^{\circ}C$ over 28% concentration. In L. lactis and Lactobacillus plantarum, VFPs fermented for 15 hours were over $2{\sim}3$ times lower than those fermented for 40 hours. Hunter's color lightness (L) and yellowness (b) were decreased according to the elevation of gelatinization temperature and fermentation time. L. lactis and L. plantarum-producing waxy rice pastes were the uniform micell type with a large air-pore size and amorphous micell type with a small air-pore size, respectively. Based on these results, L. lactis was a lower lactic acid-producing bacteria as well as uniform air-pore distribution on waxy rice paste. It was found to be a good sourpaste-fermenting strain for enhancement of quality properties of yakchobugak, as revealed through viscosity, total acidity, Hunter's color b value and scanning electron micrographs.

• Korean Journal of Food Science and Technology
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• v.25 no.6
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• pp.694-697
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• 1993

Soymilk was cultured by various human large intestinal bacteria and lactic acid bacteria; Bifidobacterium longum, Lactobacillus acidophilus, Baeteroides fragilis, Eubacterium limosum, Clostridium perfringens and Escherichia coli. Among them, only B. longum utilized raffinose and stachyose actively which are major oligosaccharides present in soymilk by producing active ${\alpha}-galactosidase$ and produced greatest acid. Number of colony forming unit of B. longum reached $1.5{\times}10^{8}$ after 16 hr culture in soymilk. Also Bifidobacterium longum produced the highest level of ${\alpha}-galactosidase,\;{\beta}-galactosidase\;and\;{\alpha}-galactosidase$, in soymilk during culture.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.119-127
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• 2013

Twenty-three strains of Leuconostoc species and 45 strains of Weissella species inhibiting the growth of Lactobacillus sakei, one of the most populous lactic acid bacteria in over-ripened kimchi, were isolated from kimchi in our previous study. Among these hetero-fermentative 68 strains, Leuconostoc mesenteroides CK0128, Weissella cibaria CK0633, and W. cibaria KK0797 exhibited a relatively high survival rate in MRS medium, which was adjusted to pH 4.3 using an acid mixture consisting of acetic and lactic acids, and produced a large amount of exopolysaccharides. The culture supernatants of 3 strains were fractionated by a molecular weight cutter and lyophilized. The fractions with a molecular weight smaller than 3,000 Da showed antagonistic activity against Staphylococcus aureus and Lb. sakei. The anti-bacterial substances were very stable to heat treatments ($121^{\circ}C$, 15 min) and active at acidic conditions below pH 5. ${\alpha}$-Amylase, lipase, and proteolytic enzymes (proteinase K and pepsin) did not affect their activities. These non-proteinaceous anti-bacterial substances inhibited the growth of several food pathogens.

• Microbiology and Biotechnology Letters
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• v.10 no.1
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• pp.9-14
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• 1982

Three common species of lactic acid bacteria, Lactobacillus casei, Lactobacillus bulgaricus, and Streptococus lartis were tried to store in frozen state for various periods up to four months and their stabilities during the storage were evaluated. A needle of culture suspension was transferred to 10 $m\ell$ of 10% reconstituted skim milk and frozen immediately. After storage under said conditions the storage tubes were thawed and incubated under optimum growth temperatures for 48 hours after which plate counts and acidity determinations were made. The same incubation and analyses were repeated with organisms transferred from the previous culture tubes. No significant deterioration in both survival and acid producing activity were observed during the four month storage except that some decrease in acid forming by L. bulgaricus appeared after 60 days of storage. Among the three species tested L. casei was found to be most stable and the fast was reconfirmed with scale-upped fermentation experiments using the same organism.

• Journal of Microbiology and Biotechnology
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• v.30 no.7
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• pp.1060-1066
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• 2020

This study was focused on developing and obtaining a kimchi starter for use in commercial kimchi production. Kimchi varieties made with selected starters are of high quality, have high levels of mannitol, and extended shelf life. The starters were screened for properties such as mannitol production, low gas/acid production, and acid resistance. Finally, kimchi fermentation testing was performed using selected LAB starters. Kimchi samples were prepared with lactic acid bacteria (LAB) starters, including Leuconostoc mesenteroides PBio03 and Leuconostoc mesenteroides PBio104. The LAB starters are isolated from kimchi and can grow under pH 3.0 and low temperature conditions of 5℃. Four kimchi samples were fermented and stored for 28 days at 5℃. The kimchi samples made with starters (PBio03 and PBio104) had better quality (production of mannitol and maintenance of heterofermentative LAB dominance) than the non-starter kimchi samples. In the starter kimchi, Leu. mesenteroides was the dominant LAB, comprising 80% and 70% of total LAB counts at 7 and 21 days, respectively. Mannitol content of the kimchi with Leu. mesenteroides PBio03 was 1,423 ± 19.1 mg/100 g at 28 days, which was higher than that of the non-starter kimchi sample (1,027 ± 12.2 mg/100 g). These results show the possibility of producing kimchi with improved qualities using Leu. mesenteroides PBio03 and PBio104 as starters.

• 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.38 no.6
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• pp.1315-1321
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• 2018

Bacteriocin is ribosomally synthesized by bacteria and inhibits closely related species. In this study we aimed at isolating lactic acid bacteria producing bacteriocin presenting anti-staphylococcal activity. A Lactococcus lactis strain was isolated from kimchi for the purpose and identified by 16S rRNA gene sequencing. As preliminary tests, optimal culture conditions, stabilities against heat, solvents, and enzymes treatments, and type of action (bacteriostatic or bactericidal) of the bacteriocin were investigated. The optimal culture conditions for production of the bacteriocin were MRS broth medium and $25^{\circ}C$ and $30^{\circ}C$ culture temperatures. The bacteriocin was acidic and the activity was abolished by a protease treatment. Its stability was maintained at $100^{\circ}C$ for 15 min and under treatments of various organic solvents such as methanol, ethanol, acetone, acetonitrile, and chloroform. Finally, the bacteriocin showed bactericidal action against Staphylococcus aureus where 200 AU/mL of the bacteriocin decreased the viable cell count (CFU/mL) of S. aureus by 2.5 log scale, compared with a control (no bacteriocin added) after 4-h incubation.