• Biotechnology and Bioprocess Engineering:BBE
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• 제2권2호
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• pp.101-104
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• 1997

Lactic acid production from ${\alpha}$-cellulose by simultaneous saccharification and fermentation (SSF) was studied. The cellulose was converted in a batch SSF using cellulase enzyme Cytolase CL to produce glucose sugar and Lactobacillus delbrueckii to ferment the glucose to lactic acid. The effects of temperature, PH, yeast extract loading, and lactic acid inhibition were studied to determine the optimum conditions for the batch processing. Cellulose was converted efficiently to lactic acid, and enzymatic hydrolysis was the rate controlling step in the SSF. The highest conversion rate was obtained at 46$^{\circ}C$ and pH 5.0. The observed yield of lactic acid from ${\alpha}$-cellulose was 0.90 at 72 hours. The optimum pH of the SSF was coincident with that of enzymatic hydrolysis. The optimum temperature of the SSF was chosen as the highest temperature the microoraganism could withstand. The optimum yeast extract loading was found to be 2.5g/L. Lactic acid was observed to be inhibitory to the microorganisms' activity.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2006년도 임시총회 및 추계학술발표회
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• pp.38-40
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• 2006

• KSBB Journal
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• 제26권1호
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• pp.13-18
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• 2011

본 연구에서는 $Ca(LA)_2$의 침전조건을 최적화하고 침전된 $Ca(LA)_2$ 용액에 황산을 처리하여 고순도, 고수율의 lactic acid를 회수할 수 있는 방법을 개발하고자 하였다. 특히 $Ca(LA)_2$의 용해도를 낮추기 위하여 여러 종류의 유기용매 첨가에 따른 영향을 평가하였다. 모델용액의 경우 침전을 위한 최적의 석회종류, 석회량, 교반속도, 시간, 온도, 유기용매 첨가량은 각각 CaO, 0.0175 g/mL, 220 rpm, 24 h, $5^{\circ}C$, ethanol 25% (v/v)이었으며 최적 조건 하에서 가장 높은 순도 (98%)와 수율(69%)을 얻을 수 있었다. 발효배양액 (lactic acid 순도: 69%, pH: 7.3)의 경우, 모델용액으로부터 얻은 최적의 조건 하에서 $Ca(LA)_2$ 회수 과정에서 64%, 회수된 $Ca(LA)_2$에 황산을 첨가 ($Ca(LA)_2/H_2SO_4$ molar ratio = 1:1)하여 lactic acid를 회수하는 과정에서 86%의 회수율을 각각 얻어 발효배양액으로부터 총괄 수율 55%로 lactic acid (순도: 88.6%)를 얻을 수 있었다.

• Journal of Biosystems Engineering
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• 제30권4호
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• pp.249-253
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• 2005

This study was carried out to develop enzyme biosensor for lactic acid bacteria. Lactic acids produced by lactic acid bacteria (LAB) was measured and good correlation $R^2=0.98$ between LAB count and lactic acids concentration was found. Hydrogen ion produced by L-lactate dehydrogenase (L-LDH) was measured by a potentiometer. Glutamic-pyruvic transminase (GPT) was used for eliminating inhibitor in the reaction. Polyacrylamide gel was used for immobilizing matrix of the sensor. The biosensor was tested and showed good feasibility with $R^2=0.99$ on validation.

• KSBB Journal
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• 제26권6호
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• pp.477-482
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• 2011

There has been a growing attention on PDLA (poly D-lactic acid) since stereocomplex PLA, a kind of polymer alloy between PLLA and PDLA was known much thermally stable compared PLLA. Superior characteristics of stereocomplex PLA result in the elevated demand for D-lactic acid. Although many research works have been reported for L-lactic acid production especially food industry, however there are relatively few research works for D-lactic acid production since D-lactic acid cannot find any applications in food industry. Most imminent issue for D-lactic acid is the economic production process that requires low cost medium, efficient lactic acid producing microorganism and finally large scale-up design. In this review, current status of D-lactic acid production process will be summarized and discussed for the further improvement of D-lactic acid production process.

• Journal of Microbiology and Biotechnology
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• 제24권5호
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• pp.661-666
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• 2014

Both lactic acid productivity and cell growth were linearly correlated with yeast extract supplementation in batch fermentation. During conventional continuous operation, although fresh feed was introduced into the bioreactor with a significantly low dilution rate (0.04 $h^{-1}$), the amount of yeast extract employed was not enough to maintain the growth of microorganism. However, when the fresh feed contained 100 g/l glucose and 2 g/l yeast extract during cell-recycle continuous operation at a dilution rate of 0.04 $h^{-1}$, more than 90 g/l lactic acid was continuously produced, with the average productivity of 3.72 $g/l{\cdot}h$. In this experiment, 82 g of yeast extract (77% of reduction yield) could be reduced for the production of 1 kg of lactic acid compared with batch fermentation of a similar volumetric productivity.

• 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 Microbiology and Biotechnology
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• 제26권6호
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• pp.1148-1161
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• 2016

Lactobacilli are universally recognized as probiotics that are widely used in the adjuvant treatment of inflammatory diseases, such as vaginitis and enteritis. With the overuse of antibiotics in recent years, the lactobacilli in the human body are killed, which could disrupt the microecological balance in the human body and affect health adversely. In this work, cephalosporin-resistant Lactobacillus casei RL20 was obtained successfully from the feces of healthy volunteers, which possessed a stable genetic set. However, the shortage of lactic acid (72.0 g/l at 48 h) by fermentation did not meet the requirement for its use in medicine. To increase the production of lactic acid, the functional genes pfk and glk were introduced into the wild strain. A yield of 144.2 g/l lactic acid was obtained in the transgenic L. casei RL20-2 after fermentation for 48 h in 1 L of basic fermentation medium with an initial glucose concentration of 100 g/l and increasing antibacterial activity. These data suggested that L. casei RL20-2 that exhibited a high yield of lactic acid may be a potential probiotic to inhibit the spread of bacterial infectious diseases and may be used for vaginitis therapy.

• 한국식품저장유통학회지
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• 제31권1호
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• pp.161-172
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• 2024

본 연구에서는 모싯잎 에탄올 추출물이 첨가된 산업용 배지에 유산균(L. plantarum JBLAB0101와 L. rhamnosus GG(LGG)) 발효특성을 확인하였고, 발효물에 대한 항비만 효능 분석을 수행하였다. 유산균 발효기간 중 이화학적특성(pH, 총산도), 생균수, 유기산 및 유리당 함량을 분석하였다. 생균수는 발효 4일 차에 최대치로 8.75-8.85 log CFU/mL로 확인되었으며, 이에 따라 pH는 6.58-6.66에서 3.74-3.79로 감소하였고, 총산도는 0.39-0.40%에서 2.07-2.19%로 증가하였다. Lactic acid는 발효 4일 차에 1,676.03-1,910.12 mg%로 증가하였으며, glucose는 L. plantarum 균주에서 모두 소모되었고, LGG 균주는 348.35 mg% 잔존하였다. 항비만 효능 평가는 pancreatic lipase 저해활성과 3T3-L1 세포주를 이용한 지질분화억제능(지질축적률, 렙틴 생성량 및 PPAR-γ 및 SREBP-1c 유전자의 mRNA 발현량)을 분석하였다. 모싯잎 추출물 첨가 산업용 배지에 접종된 균주의 이름과 배양유무에 따라 비발효물(UFRL), JBLAB0101 발효물(FRLPLA) 및 LGG 발효물(FRLLGG)로 구분하였다. Lipase 저해활성은 UFRL, FRLPLA 및 FRLLGG을 동일농도 0.5 mg/mL에 처리 시 각각 12.19%, 30.10% 및 25.63%로 확인되었다. 3T3-L1 세포주에 FRLPLA를 200 ㎍/mL 처리함에 따라 비처리구에 비해 지질축적률, 렙틴 생성량, PPAR-γ 및 SREBP-1c 유전자의 mRNA 발현량이 각각 37.54%, 54.64%, 24.18% 및 31.32% 감소하였다. 이와 같은 결과로 항비만 효능이 있는 모싯잎 추출물이 첨가된 산업용 배지에 L. plantarum JBLAB0101 균주와 LGG 균주의 유산발효가 항비만 효능 증진 가능성이 기대된다.

• 한국식품영양과학회지
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• 제28권4호
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• pp.805-809
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• 1999

The growth of Lactobacillus casei in milk was enhanced by adding yams. Addition of 1% yam(raw or dry) promoted the cell growth and acid production in fermented milk. The milk containing 1% yams formed the complete curd by lactic acid fermentation at 37oC for 19hr while the milk without yams showed the incomplete curd formation. The crude mucilage extracted from a raw yam also enhanced the cell growth as well as the acid production. Addition of mucilage(0.08%) showed the similar effects with adding heat treated yam(1%). The milk fermented by adding various yams showed the high scores for sensory evaluation comparing with the milk fermented without yams. The fermenting ability of Lactobacillus acidophilus, Lactobacillus kefir and Leuconostoc mesenteroides was evaluated by adding 1% of a dry yam in milk. A dry yam also enhanced the cell growth of L. acidophilus resulting in the high acid production. The viable cell counts of L. casei, L. acidophilus and Leuc. mesenteroides except L. kefir were increased by adding 1% of a dry yam.