• 한국식품과학회지
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• 제30권1호
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• pp.168-174
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• 1998

이 연구는 발효유 제조시 사용되는 Lactobacillus acidophilus NCFM이 생산하는 lactic acid의 생성변이를 조사하므로써 발효유 제조시 D(-)-lactic acid의 함량을 최소화하고 보존 중의 D(-)-lactic acid의 함량도 최소화하므로써 보다 인체에 유익한 발효유의 제조를 위한 기초적인 정보를 제공하기 위하여 실시되었으며, 그 결과는 다음과 같다. 발효온도는 $37^{\circ}C$에서 산생성이 가장 우수하였으며, D(-)-lactic acid의 비율도 가장 낮았다. 보존온도에 따른 변이에서는 저온에서 후산생성도 적었으며, D(-)-lactic acid의 비율도 가장 낮았다. 또한 처리에 따른 산생성에서는 호기상태에서 산생성이 가장 우수하였으며, D(-)-lactic acid의 함량이 가장 낮았다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권1호
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• pp.52-58
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• 2004

An unstructured mathematical model for lactic acid fermentation was developed. This model was able to predict the inhibition effects of lactic acid and glucose and was con-firmed to be valid with various initial concentrations of lactic acid and glucose. Simulation of energy production was made using this mathematical model, and the relationship between the kinetics of energy metabolism and lactic acid production was also analyzed.

• 약학회지
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• 제49권6호
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• pp.459-464
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• 2005

The immune reinforcement of the probiotic lactic acid bacteria Lactobacillus acidophilus, Streptococcus thermophilus and Bifidobacterium bifidum was studied in RAW 264.7 cell line treated with diluted solution (dilution to $2^{5}$) of the supernatnats of lactic acid bacteria. RAW 264.7 cell line was used as a macrophage model to assess the effects of lactic acid bacteria on the production of nitric oxide (NO) and cytokine tumor necrosis factor (TNF)-$\alpha$ and cell morphological changes. The production of NO and TNF-$\alpha$ were largely affected by lactic acid bacteria in dose-dependent manner in 24 or 48 hr cultures and cell morphological changes were also largely affected by lactic acid bacteria. Especially Bifidobacterium bifidum differentially stimulated the production of NO and TNF-$\alpha$. NO production was increased by Bifidobacterium bifidum 25 $\mu$l/ml more than LPS (20 ng/ml) control, and TW-$\alpha$ by Bifidobacterium bifidum 6.25 $\mu$l/ml more than LPS (10 ng/ml) control. The in vitro approaches employed here should be useful in further characterization of the effects of lactic acid bacteria on systemic immunity.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.181-185
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• 2005

We investigated the fermentative production of lactic acid from cheese whey and corn steep liquor as cheap raw materials using Lactobacillus sp. RKY2 to reduce the manufacturing cost of lactic acid. Lactic acid yields were obtained at more than 0.98 g/g from medium containing whey lactose. Lactic aid productivities and yields obtained from whey lactose were slightly higher than those obtained from pure lactose. The final concentration of lactic acid increased with increase, in whey lactose concentration, whereas the lactic acid productivity decreased probably due to substrate inhibition. The fermentation efficiencies were improved by addition of more corn steep liquor to the medium.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.259-262
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• 2003

In this study, batch production of lactic acid from cheap law material such as barley, wheat, and corn, was tried to lower the total production cost of lactic acid. Although no nutrients were supplemented, lactic acid productivities were achieved up to 0.88 $g/(L{\cdot}hr)$ from barley, wheat and com enzymatic hydrolysate. By adding corn steep liquor to com and wheat hydrolysate media, realtively high lactic acid $productivities(4.14\;g/(L{\cdot}hr))$ were obtained.

• Journal of Dairy Science and Biotechnology
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• 제29권1호
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• pp.55-58
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• 2011

Certain lactic acid bacteria have anti-tumor activity, especially colon cancer. The fermented milk products containing that kind of lactic acid bacteria have to be recommended for human health as excellent health functional foods. This paper have been classified by 5 regions on the functions of lactic acid bacteria related to prevention of colon cancer. 1) Enhancing of host's immune response; Production of cytokines. 2) Binding and degradation of potential carcinogens; Binding and degradation of mutagenicity. 3) The changes of intestinal microflora and production of antitumorigenic or antimutagenic compounds; Production of azoxymethane. 4) Alteration of the metabolic activity of intestinal microflora; Decrease of harmful enzymes in intestinal tract. 5) Alteration of physicochemical conditions in the colon; Decrease of pH and bile acids contents.

• Journal of Microbiology
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• 제43권1호
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• pp.38-43
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• 2005

Lactic acid production parameter optimization using Lactobacillus amylovorus NRRL B-4542 was performed using the design of experiments (DOE) available in the form of an orthogonal array and a software for automatic design and analysis of the experiments, both based on Taguchi protocol. Optimal levels of physical parameters and key media components namely temperature, pH, inoculum size, moisture, yeast extract, $MgSO_4{\cdot}7H_20$, Tween 80, and corn steep liquor (CSL) were determined. Among the physical parameters, temperature contributed higher influence, and among media components, yeast extract, $MgSO_4{\cdot}7H_20$, and Tween 80 played important roles in the conversion of starch to lactic acid. The expected yield of lactic acid under these optimal conditions was 95.80% and the actual yield at optimum conditions was 93.50%.

• Journal of Microbiology and Biotechnology
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• 제20권1호
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• pp.101-109
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• 2010

Efficient L-lactic acid production from Jerusalem artichoke tubers, by Lactobacillus casei G-02, using simultaneous saccharification and fermentation (SSF) in a fed-batch culture, is demonstrated. A kinetic analysis of the SSF revealed that the inulinase activity was subjected to product inhibition, whereas the fermentation activity of G-02 was subjected to substrate inhibition. It was also found that the intracellular NADH oxidase (NOX) activity was enhanced by the citrate metabolism, which dramatically increased the carbon flux of the Embden-Meyerhof-Parnas (EMP) pathway, along with the production of ATP. As a result, when the SSF was carried out at $40^{\circ}C$ after an initial hydrolysis of 1 h and included a sodium citrate supplement of 10 g/l, an L-lactic acid concentration of 141.5 g/l was obtained after 30 h, with a volumetric productivity of 4.7 g/l/h. The conversion efficiency and product yield were 93.6% of the theoretical lactic acid yield and 52.4 g lactic acid/l00 g Jerusalem artichoke flour, respectively. Such a high concentration of lactic acid with a high productivity from Jerusalem artichokes has not been reported previously, making G-02 a potential candidate for the economic production of L-lactic acid from Jerusalem artichokes on a commercial scale.

• KSBB Journal
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• 제27권3호
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• pp.151-156
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• 2012

Lactic acid is an important product arising from the anaerobic fermentation by lactic acid bacteria (LAB). It is used in the pharmaceutical, cosmetic, chemical, and food industries as well as for biodegradable polymer and green solvent production. The poly lactic acid (PLA) is an important material for bio-plastic manufacturing process. For PLA production by new LAB, we screened LAB isolates from shellfish. A total of 28 LAB were isolated from various shellfishes. They were all Gram positive, oxidase and catalase negative. Based on API 50CHL kit, 7 strains among the 28 isolates were identified as Lactobacillus plantarum, 6 strains as Lactobacillus delbrueckii, 5 strains as Leuconostoc mesenteroides, 3 strains as Lactobacillus brevis, 2 strains as Lactococcus lactis, 1 strain as Lactobacillus salivarius, 1 strain as Lactobacillus paracasei, 1 strain as Lactobacillus pentosus, 1 strain as Lactobacillus fermentum and 1 strain as Pediococcus pentosaceu. Also, we examined the amount of total lactic acid produced by these new strains by HPLC analysis with Chiralpak MA column. One strain E-3 from Mytilus edulis was indentified as Lactobacillus plantarum and found to produce 20.0 g/L of D-form lactic acid from 20 g/L of dextrose. Further studies are underway to increase the D-lactic acid production by E-3.

• Journal of Microbiology and Biotechnology
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• 제25권1호
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• pp.81-88
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• 2015

This study describes a novel strategy to regulate the metabolic flux for lactic acid production in Lactobacillus casei. The ldhL gene encoding _L-lactate dehydrogenase (L-LDH) was overexpressed in L. casei, and a two-stage oxygen supply strategy (TOS) that maintained a medium oxygen supply level during the early fermentation phase, and a low oxygen supply level in the later phase was carried out. As a consequence, a maximum L-LDH activity of 95.6 U/ml was obtained in the recombinant strain, which was over 4-fold higher than that of the initial strain. Under the TOS for L. casei (pMG-ldhL), the maximum lactic acid concentration of 159.6 g/l was obtained in 36 h, corresponding to a 62.8% increase. The results presented here provide a novel way to regulate the metabolic flux of L. casei for lactic acid production in different fermentation stages, which is available to enhance organic acid production in other strains.