• Microbiology and Biotechnology Letters
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• v.27 no.1
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• pp.15-22
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• 1999

Various lactic acid bacteria were isolated from Korean Kimchi in order to study their antimutagenic substances. Ames test using Salmonella typhimurium TA98 and TA100 showed the strain KLAB21 to have the highest antimutagenic activity among the 230 isolated strains against MNNG (N-methyl-N'-nitro-N-nitrosoguanidine), NPD (4-nitro-O-phenylenediamine), NQO (4-nitrosoquinoline-1-oxide) and AFB1 (aflatoxin B1). The strain was identified as Lactobacillus plantarum based on its morphological, cultural and physiological characteristics. Antimutagenic activity of L. plantarum KLAB21 was found in culture supernatant suggesting the bacterium secrete antimutagenic substance in the media. No mutagenic activity was found in the culture supernatant. The isolated strain L. plantarum KLAB21 showed much higher antimutagenic activity than L. plantarum IAM1261 which is being used industrially for fermented milk production. The antimutagenic activity of L.plantarum KLAB21 was reconfirmed by the spore-rec assay using spores of Bacillus subtilis H17($Rec^+$) and M45($Rec^-$).

• Food Science and Preservation
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• v.5 no.4
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• pp.386-391
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• 1998

Lactobacillus plantarum KLAB21 isolated from kimchi has been shown to produce antimutagenic subtance(s) into the culture medium using Salmonella typhimurium TA100 and S. typhimurium TA98 (Rhee and Park, Korean J. Appl. Microbiol.. Biotechnol., 1999, in press). In this study, the effects of culture conditions were investigated to maximize the production of antimutagenic substance(s) against 4-nitro-O-phenylenediamine(NPD) by the strain KLAB21. Glucose(255) as a carbon source and yeast extract or bactopeptone(1%) as a nitrogen source showed the highest production of the antimutagenic substance(s). Optimal initial pH of the culture medium, culture temperature and shaking speed for the antimutagenic substance(s) production were pH 7.0, 37$^{\circ}C$ and 150rpm, respectively. Under the optimal conditions, the antimutagenic activity of L. plantarum KLAB21 culture supernatant against NPD on Salmonella typhimurium TA100 and S. typhimurium TA98 were 73.95% and 59.74%, respectively.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.417-423
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• 2000

Lactobacillus plantarum KLAB21 isolated from Kimchi has been reported to produce antimutagenic subtance(s) in the culture medium. In this study, antimutagenic effects of the strain KLAB21 were investigated to under various culture conditions maximize the production of antimutagenic substance(s) against N-methyl-N'-nitro-N-nitrosoguanidine(MNNG) on Salmonella typhimurium TA100 and 4-nitroquinoline-1-oxide(NQO) on S. typhimurium TA98. Glucose(2%) as a carbon source and yeast extract(1%) as a nitrogen source resulted in the highest production of the antimutagenic substance(s) against both mutagens in the culture supernatant of L. plantarum KLAB21. The most effective concentrations of bactopeptone as a nitrogen source were 1% against MNNG and 1.5% against NQO. Optimal pH of the medium, culture temperature, and shaking speed for the antimutagenic substance(s) production were pH 7.0, $37^{\circ}C$ and 150 rpm, respectively. Under the optimal condition, the antimutagenic effects of L. plantarum KLAB21 culture supernatant were 98.4% against MNNG on S. typhimurium TA100 and 57.3% against NQO on S. typhimurium TA98.

• Food Science and Preservation
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• v.15 no.3
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• pp.469-476
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• 2008

Lactic acid fermentation of peach juice was carried out by using Lactobacillus plantarum KLAB21, a strain with a high level of antimutagenic activity, When the fermentation was carried out at 25, 30, 37 and $40^{\circ}C$, the highest level in the viable counts and acid production was obtained at $37^{\circ}C$. The sterilized peach juice showed a higher level of viable counts and acid production than the non-sterilized juice. And more viable counts and acid production were observed in the juice fermented by L. plantarum KLAB21 only than that obtained by a mixed culture of L. plantarum KLAB21 and Leuconostoc mesenteroides cells. When the lactic acid fermentation was performed for 5 days, the first 3 days of fermentation resulted in an increase of the viable counts from 8.2 to of 9.2 of log cfu/mL which is the highest level, as well as a decrease of the residual reducing sugar content from 5.6 to 0.1 % Decrease in the viable counts and m significant changes in the residual reducing sugar content were observed for further fermentation up to 5 days. However, the titratable acid content increased and the pH value decreased during the fermentation for 5 days to reach the highest titratable acid content (1,98%) and the lowest pH value (3.14) after 5 days of fermentation. HPLC analysis of the organic acids showed 1,236 mg% of lactic acid and 841 mg% of galacturonic acid contents in the fermented juice which were not detected in the fresh juice before fermentation. Antimutagenic effects of $100\;{\mu}L$ of the fermented peach juice supernatant were shown to be 97.7% against MNNG(N-methyl-N'-nitro-N-nitrosoguanidine), and 58.3% against NPD(4-nitro-O-phenylenediamine) in Salmonella enterica serovar Typhimurium TA100.