• The Korean Journal of Physiology
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• 제26권1호
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• pp.89-97
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• 1992

In hypoxic tissue conditions, pyruvate can not enter the Krebs cycle and lactic acid, produced from pyruvate, accumulates to induce lactic acidosis. Pyruvate, However, can also be converted to alanine by glutamate pyruvate transaminase, that could be enhanced by glutamate. Therefore, it would be a fundamental measure to treat the lactic acidosis in tissue hypoxic conditions when one can convert the accumulated lactic acid, through pyruvate, to alanine. To test the above hypothesis, we induced a lactic acidosis in cats and the effect of glutamate on recovery of acid base state and removal of the lactic acid from blood were assessed and the results were compared with those of bicarbonate administration, which is one of the most frequently used conventional measure for correction of the acid base state during lactic acidosis. The results were that glutamate and combined glutamate bicarbonate solutions not only restored the acid base status completely from the lactic acidosis in an hour or two, but also restored the blood level of lactate partially. We concluded that administration of glutamate solution to convert pyruvate into alanine is effective in preventing lactic acid accumulation and treating lactic acidosis.

• 한국식품영양학회지
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• 제11권6호
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• pp.683-688
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• 1998

This study was conducted to develop optimal composition of flour brew in order to economically utilize flour brew inoculated by lactic acid bacteria as a starter(mother sponge) in bread-making. Two flour brews were prepared ; one with flour and water, the other with flour, water and NaCl. Various nutrients were added to both flour brews and Lactobacilli deMan Rogosa and Sharpe (MRS) broth to investigate the effect of them on growth and activities of Streptococcus thermophilus, Lactobacillus brevis and their mixed culture in flour brews to be tested with incubation at 37$^{\circ}C$. The growth of Streptococcus thermophilus, Lactobacillus brevis and their mixed culture was stimulated by addition of NaCl with 0.85% concentratin and more by mixed culture than by single lactic acid bacteria, resulting in 3 hrs reduction in cultivation and more by mixed culture than by single lactic acid bacteria, resulting in 3 hrs reduction in cultivation time. the addition of 3% glucose to flour brew with NaCl was observed to enhance acid productioni by mixed culture. Yeast extract greatly affected growth and activities of mixed culture of lactic acid bacteria in flour brew with NaCl and its optimum level of this additive in flour brew with NaCl was approximately 1.0%. The optimal composition of flour brew for mixed culture of lactic acid bacteria was suggested as follows; flour 100g, water 300g, NaCl 3.46g, glucose 12.48g, yeast extract 3.46g.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권1호
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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.

• Journal of Microbiology and Biotechnology
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• 제21권1호
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• pp.62-70
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• 2011

The antibacterial effects of nine lactic acid bacteria (LAB) against Campylobacter jejuni were investigated by using agar gel diffusion and co-culture assays. Some differences were recorded between the inhibition effects measured with these two methods. Only two LAB, Lb. pentosus CWBI B78 and E. faecium THT, exhibited a clear anti- Campylobacter activity in co-culture assay with dehydrated poultry excreta mixed with ground straw (DPE/GS) as the only growth substrate source. It was observed that the supplementation of such medium with a cellulase A complex (Beldem S.A.) enhanced the antimicrobial effect of both LAB strains. The co-culture medium acidification and the C. jejuni were positively correlated with the cellulase A concentration. The antibacterial effect was characterized by the lactic acid production from the homofermentative E. faecium THT and the lactic and acetic acids production from the heterofermentative Lb. pentosus CWBI B78. The antagonistic properties of LAB strains and enzyme combination could be used in strategies aiming at the reduction of Campylobacter prevalence in the poultry production chain and consequently the risk of human infection.

• 한국식품저장유통학회지
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• 제6권2호
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• pp.245-254
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• 1999

Lactic aicd bacteria(LAB)는 전통적으로 식품의 발효과정 중에 사용되는 미생물이다. Lactic acid bacteria를 이용한 bacteriocinogenic culture와 lactic acid bacteria에서 생산되는 산물은 식품의 부패에 원인이 되는 미생물과 병원성균에 대한 생육억제효과을 지니고 있다. 이러한 이유로 생선제품, 유제품. 육제품과 발효되지 않은 냉장식품 등의 식품저장에 lactic acid bacteria를 이용한 연구가 다양하게 수행되어져 오고 있었으나 과실 및 채소류에서의 lactic acid bacteria에 대한 효용가능성에 대해서는 아직까지 광범위하게 연구된 것이 없다. 따라서 lactic acid bacteria의 과일 및 채소류의 저장시 효과적이고 적용성이 넓은 보존제로서의 성공적인 이용을 위해서 식품저장과 lactic acid bacteria에 대한 특성, lactic acid bacteria의 대사산물, lactic acid bacteria의 안정성 등을 고려하여 과일 및 채소의 식품성분 및 구성요소와 미생물의 생육저해효과가 있는 대사산물과의 관계에 대한 많은 연구의 수행이 과일 및 채소제품에서 lactic acid bacteria의 식품보존제로서의 이용가능성을 평가하기 위해 필요한 점으로 사료된다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권6호
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• pp.522-527
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• 2005

Various processes which produce L-lactic acid using ammonia-tolerant mutant strain, Rhizopus sp. MK-96-1196, in a 3L airlift bioreactor were evaluated. When the fed-batch culture was carried out by keeping the glucose concentration at 30g/L, more than 140 g/L of L-lactic acid was produced with a product yield of 83%. In the case of the batch culture with 200g/L of initial glucose concentration, 121g/L of L-lactic acid was obtained but the low product yield based on the amount of glucose consumed. In the case of a continuous culture, 1.5g/L/h of the volumetric productivity with a product yield of 71% was achieved at dilution rate of $0.024\;h^{-1}$. Basis on these results three processes were evaluated by simple variable cost estimation including carbon source, steam, and waste treatment costs. The total variable costs of the fed-batch and continuous cultures were 88% and 140%, respectively, compared to that of batch culture. The fed-batch culture with high L-lactic acid concentration and high product yield decreased variable costs, and was the best-suited for the industrial production of L-lactic acid.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.312-315
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• 2005

A process for efficient recycle fed-batch culture was carried out to increase cell mass and spore production by Lactic acid bacteria isolated from Kimchi. A large quantity of cell mass obtained by feeding concentration of sugar in recycle fed-batch culture. When the high density of salt was created that the cell mass was come-down. In this study, cultured in different feeding concentration of sugar conditions. Lactic acid bacteria by recycle fed-batch culture was investigated in 2L working volume of fermenter, obtained the maximum cell mass was 15.17g/L.

• 한국식품영양과학회지
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• 제27권6호
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• pp.1059-1064
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• 1998

Fermented beverage using lactic acid bacteria isolated from kimchi was investigated. Lactic acid bacteria KL 1, KD 6, KL 4 strains from kimchi, or obtained Lactobacillus acidophilus, Lactobacillus plantarum, Leuconostoc mesenteroides with and without yeast(Saccharomyces cerevisiae) were inoculated in fruit vegetable juice for single and mixed culture fermentation. During the fermentation by bacterial strain and yeast for 1~3 days at 30oC, various fermentation behaviors were observed. The growth rate of mixed culture of KL 1 and yeast was higher than that of single culture by KL 1 alone during the fermentation. The amount of organic acid produced by the mixed culture fermentation of KL 1 and yeast was 0.82%(3 day) or 0.58%(1 day) and with the final pH of 3.3(3 day) or 4.2(1 day). These mixed culture systems of isolated strains or other bacterial strains had almost similar results of growth rate and acid production. Among several bacterial strains, KL 1 was suitable for the mixed culture fermentation with yeast in terms of desirable fermentation behavior and organoleptical quality. The selected strain, KL 1 was identified as Leuconostoc spp. through the series of tests on carbohydrate fermentation and biochemical characteristics.

• Journal of Animal Science and Technology
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• 제58권3호
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• pp.10.1-10.10
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• 2016

Background: Airag, alcoholic sour-tasting beverage, has been traditionally prepared by Mongolian nomads who naturally ferment fresh mares' milk. Biochemical and microbiological compositions of airag samples collected in Ulaanbaatar, Mongolia and physiological characteristics of isolated lactic acid bacteria were investigated. Methods: Protein composition and biochemical composition were determined using sodium dodecyl sulfate-gel electrophoresis and high performance liquid chromatography, respectively. Lactic acid bacteria were identified based on nucleotide sequence of 16S rRNA gene. Carbohydrate fermentation, acid survival, bile resistance and acid production in skim milk culture were determined. Results: Equine whey proteins were present in airag samples more than caseins. The airag samples contained 0.10-3.36 % lactose, 1.44-2.33 % ethyl alcohol, 1.08-1.62 % lactic acid and 0.12-0.22 % acetic acid. Lactobacillus (L.) helveticus were major lactic acid bacteria consisting of 9 isolates among total 18 isolates of lactic acid bacteria. L. helveticus survived strongly in PBS, pH 3.0 but did not grow in MRS broth containing 0.1 % oxgall. A couple of L. helveticus isolates lowered pH of skim milk culture to less than 4.0 and produced acid up to more than 1.0 %. Conclusion: Highly variable biochemical compositions of the airag samples indicated inconsistent quality due to natural fermentation. Airag with low lactose content should be favorable for nutrition, considering that mares' milk with high lactose content has strong laxative effect. The isolates of L. helveticus which produced acid actively in skim milk culture might have a major role in production of airag.

• 한국식품과학회지
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• 제33권5호
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• pp.603-610
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• 2001

본 연구는 분리대두단백을 세 종류의 단백분해효소로 처리하여 가수분해시킨 후 B. bifidum으로 단독배양하거나 B. bifidum과 L. acidophilus 또는 B. bifidum과 L. bulgaricus로 혼합배양하여 soy yogurt를 제조한 다음 비피더스균의 생육 특성 및 시료의 품질특성을 측정하였다. Soy yogurt에서 혼합배양의 경우 단독배양보다 pH는 더 낮았으나 산도는 더 높았으며 생균수는 더 많았다. 유기산의 함량은 혼합배양의 경우 lactic acid의 함량이 매우 많았으나 단독배양시에는 acetic acid와 succinic acid의 함량이 많았다. 또한 유리아미노산의 함량은 효소처리군의 경우 단독배양시에 혼합배양보다 많았으며 A. oryzae로부터 추출한 단백분해효소처리군에서 그 함량이 월등히 많았으나 ${\alpha}-chymotrypsin$ 처리군에서는 그 함량이 가장 적었다. 이는 효소처리군 중에서 ${\alpha}-chymotrypsin$ 처리군의 가수분해도는 가장 높았으나 그 가수분해물의 비피더스균 생육촉진 효과가 가장 적어서 유기산 및 유리아미노산의 함량이 가장 낮았고 pH가 가장 높았으며 산도는 가장 낮았고 생균수는 가장 적었다. 효소처리한 soy yogurt의 점도와 보수력은 비효소처리군보다 더 낮았으며, 특히${\alpha}-chymotrypsin$ 처리군의 점도와 보수력은 다른 효소처리군에 비해 더 높았다. 휘발성 향기성분 중 acetaldehyde, ethanol, diacetyl 및 butyl alcohol의 함량은 발효에 의해 증가되었다. 품질이 향상된 frozen soy yogurt를 개발하기 위한 중간단계로써 단백분해효소와 배양방법을 달리하여 soy yogurt를 제조하였으며, 본 연구결과를 전반적으로 종합하여 볼 때 분리대두단백을 단백분해효소로 처리하고 비피더스균에 젖산균들을 혼합배양하므로써 lactic acid 생성 및 비피더스균의 생육을 촉진시켰다.