• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2005년도 정기총회 및 제35차 춘계 학술 발표대회
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• pp.338-342
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• 2005

본 연구에서는 Kefir를 MRS선택배지에 도말하여 생장이 우수한 Lactobacillus sp. 최종 분리하였다. 분리된 Lactobacillus sp. 균은 API Kit의 당발효 시험과 16s RNA배열 분석으로부터 Lactobacillus rhamnosus로 동정되었다. Lactobacillus rhamnosus균주는 amylase와cellulase, xylanase 비활성이 0.673과 0.269, $0.288\;{\mu}mole/min/mg$으로 높은 활성을 보였다. 그리고, pH 2에서 65% 이상이 잔존하는 강한 pH내성과 1.0% 담즙산이 함유된 배지에서도 72% 생존하는 내담즙성을 나타냈으며, 열안정성도 비교적 뛰어난 것으로 확인되었다. 대장균에 Lactobacillus rhamnosus를 첨가하여 혼합배양시는 18시간이내에 대장균이 100% 사멸되었다. 이상의 결과로부터 분리된 Lactobacillus rhamnosus 균주는 probiotics 로서의 우수한 특성을 가진 것으로 확인되었다.

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2005년도 정기총회 및 제35차 춘계 학술 발표대회
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• pp.375-379
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• 2005

본 연구는 ${\beta}-galactosidase$와 phytase활성이 높은 균주의 선발을 목적으로 수각 미생물들을 Kefir와 자연환경에서 분리하여 효소활성을 측정하였다. 배양한 유산균과 효모 균체액을 French pressure cell press로 세포를 파쇄하였을 때, 각 미생물의 단백질농도는 효모보다 유산균이 높은 것으로 나타났다. ${\beta}-galcactosidase$의 비활성은 Kluyveromyces maxiranus와 Candida utilis를 제외하고는 대부분 $0.80{\sim}0.89\;umol/min/mg$ 사이였다. 체적활성의 경우는 Lactobacillus paracasei 및 Lactobacillus rahmnosus, Enterococcus faecium이 각각 15.9 및 14.5, 14.5 umol/ml를 기록하여 ${\beta}-galcactosidase$의 추출재료로 우수하였다. phytase의 비활성은 Lactobacillus paracasei 와 Enterococcus faecium이 0.032와 0.038 umol/min/mg로 가장 높았다. 체적활성의 경우는 Lactobacillus paracasei가 35.12 umol/ml로 가장 높았다. 결론적으로 ${\beta}-galactosidase$와 phytase의 생산측면에서 이용한 미생물중에서는 Lactobacillus paracasei가 가장 우수한 것으로 사료되었다.

• 한국가금학회지
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• 제43권3호
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• pp.159-167
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• 2016

A total of 528 broilers ($47{\pm}0.1g$; 1 day of age) were used in a 35-day feeding trial to evaluate probiotics, prebiotics and their interactive effects on growth performance, blood characteristics, relative organ weight and meat quality. Broilers were randomly distributed into 1 of 6 treatments on the basis of body weight (BW) (4 replicate pens per treatment, 22 broilers per pen). The dietary treatments were CON, basal diet; B, CON + 0.1 g kg-1 Bacillus subtilis; K, CON + 1 g kg-1 Kefir; G, CON + 1 g kg-1 ${\beta}-glucan$; GB, G + 1 g kg-1 Bacillus subtilis; and GK, G + 1 g kg-1 Kefir. The overall effects indicated that broilers fed the K, G and GK diets had greater body weight gain (BWG) than those fed the CON diet (P<0.05). The number of white blood cells increased (P<0.05) in the GB group compared with the CON, B and G treatments; however, the lymphocyte percentage in the B group was higher than in the G group. The weight of bursa fabricii was lower in the B and G groups compared to the K group (P<0.05), whereas a higher spleen weight was observed in chickens that were fed the GB and GK diets compared to the B group (P<0.05). The treatments did not affect the meat quality parameters, except for meat redness, which improved with all of the supplementation groups (P<0.05). The population of Lactobacillus spp. in gizzard was significantly higher in the K treatment compared with CON, B, G and GB. In conclusion, supplementation with kefir and ${\beta}-glucans$ improved growth performance.

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2004년도 정기총회 및 제33차 춘계 학술대회
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• pp.322-325
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• 2004

Kefir에서 유산균인 Lactobacillus acidophilus와 Lactococcus lactis 그리고 효모인 Candida kefir를 분리하였고, 이를 이용하여 FM(Fermented milk) A, B, C 제조${\cdot}$분석하였다. 유산균 수는 FM B가 $8.6{\times}\;10^9\;cfu/ml$로 가장 많았고, 효모수는 FM C가 $1.3{\times}\;10^7cfu/ml$로 가장 많았다. 알콜 함량은 FM C가 3.2%, FM A가 0.98%, FM B가 0.15% 였다. 아미노산은 FM A에서는 Glu, Pro, Leu, Lys, Asp 등이, FM B에서는 Glu, Leu, Pro, Lys 등이, FM C에서는 Glu, Leu, Pro, Lys 등이 주요 아미노산으로 나타났다. 지방산은 FM A, FM B, FM C 모두 palmitic acid(Cl6:0)와 oleic acid(Cl8:1)가 각각 33.5${\sim}$37.7%와 22.1${\sim}$22.4%의 수준으로 주요 지방산을 차지하였다. 관능검사 결과FM C가 가장 높은 점수를 받았으며, 다음은 FM A, FM B 순이었다.

• Journal of Microbiology and Biotechnology
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• 제29권10호
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• pp.1629-1635
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• 2019

Azo dyes are recalcitrant pollutants, which are toxic, carcinogenic, mutagenic and teratogenic, that constitute a significant burden to the environment. The decolorization and the mineralization efficiency of Remazol Brillant Orange 3R (RBO 3R) was studied using a probiotic consortium (Lactobacillus acidophilus and Lactobacillus plantarum). Biodegradation of RBO 3R (750 ppm) was investigated under shaking condition in Mineral Salt Medium (MSM) solution at pH 11.5 and temperature $25^{\circ}C$. The bio-decolorization process was further confirmed by FTIR and UV-Vis analysis. Under optimal conditions, the bacterial consortium was able to decolorize the dye completely (>99%) within 12 h. The color removal was 99.37% at 750 ppm. Muliplex PCR technique was used to detect the Lactobacillus genes. Using phytotoxicity, cytotoxicity, mutagenicity and biototoxicity endpoints, toxicological studies of RBO 3R before and after biodegradation were examined. A toxicity assay signaled that biodegradation led to detoxification of RBO 3R dye.

• Journal of Microbiology and Biotechnology
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• 제26권1호
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• pp.20-27
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• 2016

Lactobacillus kefiranofaciens ZW3 was obtained from kefir grains, which have high lactose hydrolytic activity. In this study, a heterodimeric LacLM-type β-galactosidase gene (lacLM) from ZW3 was isolated, which was composed of two overlapping genes, lacL (1,884 bp) and lacM (960 bp) encoding large and small subunits with calculated molecular masses of 73,620 and 35,682 Da, respectively. LacLM, LacL, and LacM were expressed in Escherichia coli BL21(DE3) and these recombinant proteins were purified and characterized. The results showed that, compared with the recombinant holoenzyme, the recombinant large subunit exhibits obviously lower thermostability and hydrolytic activity. Moreover, the optimal temperature and pH of the holoenzyme and large subunit are 60℃ and 7.0, and 50℃ and 8.0, respectively. However, the recombinant small subunit alone has no activity. Interestingly, the activity and thermostability of the large subunit were greatly improved after mixing it with the recombinant small subunit. Therefore, the results suggest that the small subunit might play an important role in maintaining the stability of the structure of the catalytic center located in the large subunit.

• Journal of Microbiology and Biotechnology
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• 제30권2호
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• pp.187-195
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• 2020

To understand the molecular mechanism involved in the survivability of cold-tolerant lactic acid bacteria was of great significance in food processing, since these bacteria play a key role in a variety of low-temperature fermented foods. In this study, the cold-stress response of probiotic Lactobacillus plantarum K25 isolated from Tibetan kefir grains was analyzed by iTRAQ proteomic method. By comparing differentially expressed (DE) protein profiles of the strain incubated at 10℃ and 37℃, 506 DE proteins were identified. The DE proteins involved in carbohydrate, amino acid and fatty acid biosynthesis and metabolism were significantly down-regulated, leading to a specific energy conservation survival mode. The DE proteins related to DNA repair, transcription and translation were up-regulated, implicating change of gene expression and more protein biosynthesis needed in response to cold stress. In addition, two-component system, quorum sensing and ABC (ATP-binding cassette) transporters also participated in cell cold-adaptation process. These findings provide novel insight into the cold-resistance mechanism in L. plantarum with potential application in low temperature fermented or preserved foods.

• 한국식품영양과학회지
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• 제44권4호
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• pp.602-609
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• 2015

한국 전통 발효유인 타락을 제조하기 위하여 4종의 시판 막걸리와 시판 우유를 사용한 '타락'을 제조하여 발효 특성을 분석하였으며 관여 미생물을 분석하였다. 제조된 타락에서의 pH는 발효시간에 따라 유의적으로(P<0.001) 감소되어 pH 5.56~6.49를 나타내고 산도는 유의적으로(P<0.001) 증가하여 0.17~0.40%의 값을 나타내었다. 점도는 유청이 분리되기 전까지 유의적으로(P<0.001) 증가하였다. 당도는 유의적으로(P<0.001) 감소하였다. 에탄올 함량은 시간에 따라 증가하여 발효 24시간에 0.51~0.71 mg/mL를 나타내었다. 발효산물로는 주된 유기산이 lactic acid로 발효시간에 따라 점차 증가하여 발효 24시간에서는 모든 시료에서 전체 유기산 생성량의 80% 이상을 차지하였으며 이외에 미량의 acetic acid, citric acid, succinic acid도 검출되었다. 발효와 더불어 검출된 주된 유리당은 lactose였고 소량의 glucose가 나타났다. 타락의 젖산균 수는 발효시간에 따라 증가하여 발효 24시간에는 9.87~10.41 log CFU/mL로 나타났으며 효모 수는 6.99~7.73 log CFU/mL였다. 타락에서의 분리된 균주는 효모인 Saccharomyces cerevisiae와 다양한 Pediococcus acidilactici, Lactobacillus fermentum, Leuconostoc mesenteroides 등의 다양한 젖산균이 나타났다. 따라서 타락은 효모와 젖산균이 공존하는 효모-젖산균 발효유임을 알 수 있었다.