• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.1
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• pp.23-28
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• 2005

Lactic acid is a green chemical that can be used as a raw material for biodegradable polymer. To produce lactic acid through microbial fermentation, we previously screened a novel lactic acid bacterium. In this work, we optimized lactic acid fermentation using a newly isolated and homofermentative lactic acid bacterium. The optimum medium components were found to be glucose, yeast extract, $(NH_4)_{2}HPO_4,\;and\;MnSO_4$. The optimum pH and temperature for a batch culture of Lactobacillus sp. RKY2 was found to be 6.0 and $36^{\circ}C$, respectively. Under the optimized culture conditions, the maximum lactic acid concentration (153.9 g/L) was obtained from 200 g/L of glucose and 15 g/L of yeast extract, and maximum lactic acid productivity ($6.21\;gL^{-1}h^{-1}$) was obtained from 100 g/L of glucose and 20 g/L of yeast extract. In all cases, the lactic acid yields were found to be above 0.91 g/g. This article provides the optimized conditions for a batch culture of Lactobacillus sp. RKY2, which resulted in highest productivity of lactic acid.

• The Korean Journal of Food And Nutrition
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• v.1 no.2
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• pp.95-101
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• 1988

In order to produce lactic acid and calcium lactate very useful for foods and medical supplies, lactic acid fermentation was studied by Lactobacillus sporogenes, a spore forming lactic acid bacterium. When this bacterium was cultured aerobically in the spore forming medium, the spore forming rate was 96.0% as total cell number 20$\times$108/ml, spore number 19.2$\times$108/ml. One minute agitating every 1 hour in the flask culture, or agitation of 100rpm in the fermenter was most efficient to continue to ferment at 45$^{\circ}C$ for 4days in the fermentation medium containing 10% glucose as carbohydrate and CaCO3 as a neutralizing agent. This homofermentative lactic acid bacterium showed fermentation yield of 99.3% and more than 98.2% of the yield was L(+)-lactic acid.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.1
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• pp.67-72
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• 2005

To achieve demineralization of crab shell waste by chemical and biological treatments, lactic acid and lactic acid bacterium were applied. In 5.0 and $10\%$ lactic acid, pH rapidly decreased from 6.8 to 4.2 and from 4.5 to 2.4 at day 3, respectively, and thereafter the pH remained at an almost constant level. In a $10\%$ lactic acid bacterium inoculum, pH lowered to 4.6 at day 5. Relative residual ash content rapidly decreased to 49.1 and $16.4\%$ in 5 and $10\%$ lactic acid treatments, respectively, for the initial 12 h. In 2.5, 5 and $10\%$ lactic acid bacterium inoculums, relative residual ash content rapidly decreased to 55.2, 40.9 and $44.7\%$, respectively, on the first day. Residual dry masses were 76.4, 67.8 and $46.6\%$ in 2.5, 5 and $10\%$ lactic acid treatments, respectively, for the initial 12 h. After a one-time exchange of the lactic acid solution, in the $5.0\%$ lactic acid treatment, residual dry mass rapidly decreased from 66.0 to $41.4\%$. In 2.5, 5 and $10\%$ lactic acid bacterium inoculums, residual dry masses decreased to 67.6, 57.4 and $59.6\%$ respectively, on the first day. Protein contents after demineralization ranged from $51.3{\sim}54.7\%$ in the chemical treatments and decreased to $32.3\%$ in the lactic acid fermentation process. A negative relationship was shown between pH and demineralization rate in lactic acid and lactic acid bacterium treatments. These results suggest that lactic acid fermentation can be an alternative for demineralization of crab shells, even though the rate and efficiency of the demineralization is lower than the chemical treatment.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.4
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• pp.303-308
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• 2004

We isolated a novel lactic acid bacterium from a Korean traditional fermented food, soybean paste. The newly isolated strain, dubbed RKY2, grew well on glucose, sucrose, galactose, and fructose, but it could not utilize xylose, starch, or glycerol. When the partially amplified 16S rDNA sequence (772 bp) of the strain RKY2 was compared with 10 reference strains, it was found to be most similar to Lactobacillus pentosus JCM $1588^T$, with 99.74% similarity. There-fore, the strain RKY2 was renamed Lactobacillus sp. RKY2, which has been deposited in the Korean Collection for Type Cultures as KCTC 10353BP. Lactobacillus sp. RKY2 was found to be a homofermentative lactic acid bacterium, because its end-product from glucose metabolism was found to be mainly lactic acid. It could produce more than 90 g/L of lactic acid from MRS medium supplemented with 100 g/L of glucose, with 5.2 g $L^-1$ $h^-1$ of productivity and 0.95 g/g of lactic acid yield.

• Korean Journal of Pharmacognosy
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• v.18 no.1
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• pp.34-40
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• 1987

Onion extracts were tested for effects on the growth and lactic acid production of Lactobacillus bulgaricus in the medium containing mercury. The media containing mercury were added with onion extracts and inoculated with the bacterium and then incubated at $39^{\circ}$ for four days. All of the onion extracts examined increased the growth and lactic acid production of the bacterium in the medium containing mercury. At the addition of the edible portion extract of onion to the medium containing 5 ppm, 10 ppm and 20 ppm mercury, the higher the concentration of the onion extract was added, the greater the increasing effect on the growth and lactic acid production. The brown peel extract of onion increased the growth and lactic acid production of the bacterium in the medium containing mercury at all concentrations. The higher the concentration of the extract added, the more effective the increasing effect. The onion solutions of edible portion and brown peel extracted at $90^{\circ}\;to\;100^{\circ}$ showed more desirable effects than those extracted at the room temperature. Among four kinds of the onion extracts, the brown peel solution extracted at $90^{\circ}\;to\;100^{\circ}$ was the most effective in increase of the growth and lactic acid production in the medium containing mercury.

• KSBB Journal
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• v.17 no.4
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• pp.333-338
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• 2002

This study was targeted to isolate and characterize a bacterium producing lactic acid in a large amount. Lactic acid bacteria of about fifty strains were isolated from kimchi, a Korean traditional fermented vegetable food. Strain KH-1 of them was most effective in the lactic acid production and showed 99% homology with Lactobacillus casei from analysis of 16S rRNA sequencing. The conversion ratio of lactic acid from glucose by 1. casei KH-1 was 98% in anaerobic condition, and the lactic acid was composed as racemic mixture of D(-)-and L(+)-lactic acid, 7% and 93%, respectively. This result indicated that L. casei KH-1 was a homofermentative bacterium mainly producing L(+)-lactic acid. The strain KH-1 used glucose as a preferential substrate but not utilized lactose. In investigation of more inexpensive nitrogen source for cultivation of strain KH-1 using industrial MRS medium, when yeast extract and corn steep liquor were used at the ratio of 1 to 1, the molar yield of lactic acid produced per mole of glucose(Yp/s) was 1.09.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.7
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• pp.1180-1185
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• 2004

This study was conducted to investigate the optimum conditions for the medium composition after isolating and identifying yeast and lactic acid bacteria from sourdough. It was found that the best quality lactic acid bacterium with acid product and flavor was identified as Leuconostoc species among isolated 115 lactic acid bacteria, the best Quality yeast with good fermentation and flavor was identified as Saccharomyces species among isolated 8 yeast. While the microbial growth with glucose or sucrose as sugar source was good, it was, selected that sucrose which is using commercially is better than glucose. The growth of lactic acid bacterium ; was good with 1％ added sucrose whereas yeast needed more growth. Additionally, the medium for the optimum 1 growth of the yeast was composed of 0.5％ wheat flour, 0.5％ peptone and 3％ sucrose, whereas lactic acid bacterium was composed of 0.5％ wheat flour and 1％ sucrose without peptone.

• International Journal of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.82-92
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• 2021

Purpose: It has been reported that the diversity and abundance of microbes in the vagina decrease due to the use of antimicrobial agents, and the high recurrence rate of female vaginitis due to this suggests that a new treatment is needed. Methods: In the experiment, we detected that 10% potassium sorbate solution, 1% eucalyptus oil solution, 1% tea tree oil solution, 400 µL/10 mL grapefruit seed extract solution, 100% lactic acid, 10% acetic acid solution, and 10% lactic acid solution were prepared and used. After adjusting the pH to 4, 5, and 6 with lactic acid and acetic acid in the mixed culture medium, each bacterium was inoculated into the medium and incubated for 72 h at 35℃. Incubate and 0 h each. 24 h. 48 h. The number of bacteria was measured after 72 h. Results: In the mixed culture test between lactic acid bacteria and pathogenic microorganisms, lactic acid bacteria showed good results at pH 5-5.5. Potassium sorbate, which has varying antibacterial activity based on the pH, killed pathogenic bacteria and allowed lactic acid bacteria to survive at pH 5.5. Conclusion: The formulation ratio obtained through this study could be used for the development of a feminine cleanser that can be used as a substitute for antibacterial agents. Further, the findings of this study may be able to solve the problem of antimicrobial resistance in the future.

• Microbiology and Biotechnology Letters
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• v.43 no.3
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• pp.286-290
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• 2015

Lactic acid is a useful platform chemical for a wide range of food and industrial applications such as pharmaceuticals and cosmetics. Among 313 strains of lactic acid bacteria isolated from different traditional Korean fermented foods, eight Lactobacillus strains effectively utilized xylose as a carbon source to produce lactic acid. A lactic acid bacterium identified as Lactobacillus buchneri produced the highest amount of lactic acid from xylose under anaerobic conditions. The optimum xylose concentration and incubation temperature were 50 g/l and 37℃, respectively; under these conditions, 22.3 g/l lactic acid was produced.

• Journal of Applied Biological Chemistry
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• v.43 no.4
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• pp.264-268
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• 2000

High activity of acidic ethylacetate extract from the culture supernatant of ginseng growth-promoting bacterium Pseudomonas fluorescens KGPP 207 and its fractions were demonstrated through wheat coleoptile bioassay. The following auxins and auxin-like compounds were identified in these fractions by combined gas chromatography-mass spectrometry: indole-3-acetic acid, indole-3-acetic acid methyl and ethyl ester, indole-3-butyric acid, indole-3-lactic acid and its methyl ester, indole-3-propionic acid, indole-3-pyruvic acid, p-hydroxyphenyl acetic acid, p-hydroxyphenyl acetic acid methyl and ethyl ester, phenyl acetic acid and its methyl ester. The bacterium KGPP 207 belongs to the strain of P. fluorescens which produces plant growth regulators and its beneficial effect on the ginseng growth may be due to the formation of the identified compounds.