• 한국축산식품학회지
• /
• 제31권4호
• /
• pp.513-520
• /
• 2011

In order to develop a new starter culture for fermented milk, Lactobacillus fermentum LC272 was isolated from raw milk and its physiological characteristics were investigated. The vitamin $K_2$ concentration of L. fermentum LC272 was $184.94{\mu}g/L$ in Rogosa medium and $63.93{\mu}g/L$ in the reconstituted skim milk. The optimum growth temperature for L. fermentum LC272 was determined to be $40^{\circ}C$ and it took 24 h for the pH to reach 5.2 under this condition. L. fermentum LC272 was more sensitive to rifampicin relative of the other 15 different antibiotics tested, and showed most resistance to streptomycin. L. fermentum LC272 showed higher activities to leucine arylamidase and acid phosphatase. It was comparatively tolerant to bile juice and acid and displayed high resistance against Salmonella Typhimurium and Staphylococcus aureus with rates of 82.9 and 86.3% respectively. These results demonstrated that L. fermentum LC272 could be an excellent starter culture for fermented milk with high levels of vitamin $K_2$ production.

• 한국축산식품학회지
• /
• 제30권6호
• /
• pp.957-965
• /
• 2010

To develop a new starter culture for fermented milk, Streptococcus macedonicus LC743 was isolated from raw milk and its physiological characteristics were investigated. S. macedonicus LC743 showed good immunomodulating activity compared to the index LAB starters tested. The optimum growth temperature of S. macedonicus LC743 was $40^{\circ}C$, and it took 18 h to reach pH 4.34 under these conditions. S. macedonicus LC743 showed higher sensitivity to novobiocin in a comparison of 15 different antibiotics and showed the highest resistance to gentamycin. It also showed higher activities of leucine arylamidase and acid phosphatase. Moreover, it was comparatively tolerant to bile juice and acid and displayed high resistance to Escherichia coli, Salmonella Typhimurium, Staphylococcus aureus with rates of 80.0%, 68.42%, and 81.54% respectively. These results demonstrate that S. macedonicus LC743 could be an excellent starter culture for fermented milk with a high level of immunomodulating activity.

• 한국미생물·생명공학회지
• /
• 제44권2호
• /
• pp.201-207
• /
• 2016

건강한 닭의 맹장에서 분리한 Lactobacillus sakei LAB 2와 LAB 8의 생균제로 이용을 알아보기 위해 기본적인 특성과 면역활성을 시험하였다. LAB 2와 LAB 8은 높은 내산성과 내담즙성을 가지고 있으며, 1차 대사산물인 유기산에 기인한 항균활성을 보였다. Salmonella 종을 병원성균으로 이용하여 최대 항균력을 나타내는 시간을 시험한 결과 48시간으로 나타났으며, 생성된 유기산 중 젖산의 생산량은 다른 Lactobacillus 균주보다 높게 조사되었다. In vitro 모델로 알아본 면역증진효과는 면역관련 세포의 증식과 사이토카인의 생산량 증가로 확인하였다. 이에 Lactobacillus sakei LAB 2와 LAB 8은 유용한 생균제로 개발할 수 있는 균으로 생각된다.

• 생명과학회지
• /
• 제24권2호
• /
• pp.161-166
• /
• 2014

신규 프로바이오틱스 균주로서 사용하기 위하여 한국의 염장 발효 생선가공품인 젖갈로부터 Paenibacillus sp. 균주들을 탐색하였다. 이들 균주들 중에서 BCNU 5016은 그람양성균으로 gelatinase와 urease를 생산하지 않는 전형적인 Paenibacillus sp. 균주로 확인되었다. 이 균주는 16S rDNA 염기서열 분석을 바탕으로 계통적으로 Paenibacillus polymyxa의 근연종임이 확인되었다. Paenibacillus sp. BCNU 5016은 내산성 실험을 통해 pH 2.5에서 3h 배양 후에도 91.89%까지 생존함이 확인되었고, 담즙산에도 뛰어난 내성이 있음이 확인되었다. 또한 BCNU 5016은 자가응집능, 공동응집능 및 소수성 능력으로 볼 때 우수한 장점막 부착능력을 가지고 있는 것으로 판단된다. 그러므로 Paenibacillus sp. BCNU 5016은 프로바이오틱스 균주로서 우수한 잠재력을 가지고 있음을 확인할 수 있었다.

• 한국미생물·생명공학회지
• /
• 제47권4호
• /
• pp.498-508
• /
• 2019

Bacillus species were isolated from iru, a traditional fermented condiment in Nigeria. Polyphasic approach was used to evaluate the phylogenetic relationship and strain sub-type of the isolated species. Additionally, the phylogenetic profiles of the species isolated from iru were compared with those of bacilli isolated from different continents. The phylogenetic diversity analysis was performed using the combination of 16S rRNA gene sequencing, ITS-PCR, ITS-PCR-RFLP, and M13 RAPD-PCR. The analysis revealed that Bacillus subtilis U170B and B. subtilis U146A isolated from iru were the closest relatives of strains belonging to the phylogeny of B. subtilis sensu stricto and were related to other bacilli isolated from different continents that had functional benefits. The two isolated species exhibited resistance to acidic pH (pH 2.0). The survival rates of B. subtilis U170B, B. subtilis U146A, and B. clausii UBBC-07 (commercial probiotic strain) cultured at pH 2.0 for 3 h were 33.45, 12.44, and 9.53%, respectively. The strains were highly tolerant to bile salts [0.3% (w/v)]. B. subtilis U170B exhibited the highest cell viability (43.45%) when cultured for 3 h in the presence of bile salts, followed by B. subtilis U146A (25%) and B. clausii UBBC-07 (18.94%). B. subtilis U170B and B. subtilis U146A did not exhibit haemolytic activity and were susceptible to different antibiotics. Additionally, these two strains exhibited weak antagonistic activity against B. cereus. The diverse wild strains of B. subtilis can be used as a safe multifunctional starter culture for the industrial production of condiments with health benefits.

• 한국미생물학회:학술대회논문집
• /
• 한국미생물학회 2002년도 추계학술대회
• /
• pp.59-62
• /
• 2002

The role of a TolC homologue in the virulence of Vibrio vulnificus, a marine bacterium causing serious wound infection and fulminant septicemia in persons with underlying conditions, has been studied. TolC, an outer membrane protein, has been implicated in a variety of bacterial functions including export of diverse molecules ranging from large proteins to antibiotics. A homologue of the tolC gene of V. cholerae, which has been shown to be required for bile resistance, cytotoxicity and colonization of this organism, was identified in the partially determined genome sequence of V. vulnificus. To determine the role of TolC in the virulence of V. vulnificus, a TolC-deficient (TD) mutant was isolated by in vivo allelic exchange. Compared with the parent strain, the TD mutant was more sensitive to bile, and much less virulent in mice challenged subcutaneously. This mutant was noncytotoxic to the HEp-2 cells, but its metalloprotease and cytolysin activities in the culture supernatant were comparable to the parent strain. In addition, the resistance of the TD mutant to human serum bactericidal activity as well as its growth in either human or murine blood was not affected. Collectively, our data suggest that TolC may be involved in colonization and/or spread of V. vulnificus to the blood stream, probably by secreting a cytotoxin other than the cytolysin.

• 미생물학회지
• /
• 제45권2호
• /
• pp.177-184
• /
• 2009

우수한 생균제를 개발하기 위하여 안전성이 알려진 유산균을 대상으로 인체의 분변으로부터 300여 균주를 분리하고 내산성, 내담즙성, 내열성, 항균력, 항암 및 항바이러스 효과를 가지는 균주들을 선발하여 생균제 특성을 나타내는지를 알아보기 위해 본 실험을 수행하였다. 인체에서 분리한 여러 균주 중 Miny-148 균주는 낮은 pH 및 높은 담즙산에 대한 내성, 열처리에 대한 열안정성을 지녀 기초적인 probiotic 특성을 가진 균주로 선발되어, Lactobacillus pentosus (99.9% 상동성)로 동정되었다. 항균력 실험에서 Escherichia coli O157:H7을 비롯한 Shigella flexneri, Bacillus anthracis, Staphylococcus aureus, E. coli, Vibrio cholerae, V. vulnificus, Salmonella typhimurium, 그리고 및 methicillin-resistant S. aureus (MRSA) 균주 8종 등 총 16종의 병원성세균을 억제하였다. 또한 Miny-148은 결장암 세포인 HT-29 cell을 억제하였을 뿐 아니라, transmissible gastroenteritis virus의 생육을 저해하여 세포변성 억제효과를 가진 우수한 probiotic 특성을 지닌 균주로 분석되었다.

• 한국식품과학회지
• /
• 제35권6호
• /
• pp.1244-1247
• /
• 2003

발효 및 유산균 제품에 모유만을 먹은 생후 3개월된 유아의 분변으로부터 bromocresol pule을 함유한 MRS 배지에서 노란색의 집락을 형성하는 균주들을 내산성 및 담즙산 내성이 우수한 13종의 Lactobacillus 균주들을 분리하였으며 당발효성 및 생화학적 실험을 토대로 분리된 유산균들을 동정하였다. 최종적으로 선발한 균주를 L. acidophilus로 KY1909로 명명하였다. Lactic acid 생성 능력을 평가한 후 이성질체를 분석한 결과 상업적으로 이용되는 L. acidophilus NCFM, L. acidophilus CH5, L. acidophilus NOCKS 균주들은 전체 lactic acid 중에서 L(+) form이 차지하는 비율이 각각 52.49, 40.63 및 63.13%로 나타났으나, L. acidophilus KY1909는 L(+) lactic acid의 비율이 93.96%로 나타났다.

• Journal of Microbiology and Biotechnology
• /
• 제18권7호
• /
• pp.1266-1273
• /
• 2008

Lactic acid bacteria (LAB) with antimicrobial activity and high exopolysaccharide (EPS) production ability isolated from sourdough were studied for their fermentation characteristics as potential new starter cultures. The values of pH, titratable acidity, and viable cell counts were $4.06{\pm}0.009-4.50{\pm}0.015,\;0.787{\pm}0.020%-1.172{\pm}0.018%,\;and\;8.78{\pm}0.08-8.98{\pm}0.06$ log CFU/ml, respectively. In order to select probiotics with a high survival rate in the gut, isolates were tested to assess resistance against the artificial gastric acid and bile juice. Viable LAB counts were significantly (p<0.05) affected by the acidity. At pH 2.0, the total declines in the initial bacterial counts were 4.52$\pm$0.07 log for S. thermophilus St-Body-1, >7.98$\pm$0.03 log for E. flavescens DU-10, >7.95$\pm$0.05 log for E. faecium DU-12, and 3.15$\pm$0.06 log for L. amylovorus DU-21. Among the strains, L. amylovorus DU-21 was the only strain that had bile tolerance under simulated gastrointestinal conditions. In order to improve EPS production by L. amylovorus DU-21, the influence of carbon source was studied. When glucose was used as a carbon source, EPS production dramatically increased to 17.19$\pm$0.28 g/l (p<0.05). The maximum cell growth (10.012$\pm$>0.012 log CFU/ml) and EPS production (18.71$\pm$0.19 g/l) were achieved when 15 g/l of glucose was employed as the carbon source.

• 한국축산식품학회지
• /
• 제39권5호
• /
• pp.844-861
• /
• 2019

Over the last few years, marine environment was found to be a source of surplus natural products and microorganisms with new bioactive secondary metabolites of interest which can divulge nutritional and biological impact on the host. This study aims to assess the possible, inherent and functional probiotic properties of a novel probiotic strain Enterococcus durans F3 (E. durans F3) isolated from the gut of fresh water fish Catla catla. Parameters for evaluating and describing the probiotics described in FAD/WHO guidelines were followed. E. durans F3 demonstrated affirmative results including simulated bile, acid and gastric juice tolerance with exhibited significant bactericidal effect against pathogens Staphylococcus aureus, Salmonella Typhi, Escherichia coli and Pseudomonas aeruginosa. This can be due to the enterocin produced by E. durans F3 strain, which was resolute by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) gel with amplification of the anticipated fragment of a structural gene; enterocin A, followed by antibiotic susceptibility assessment. Effective antioxidant potentiality against ${\alpha}$-diphenyl-${\alpha}$-picrylhydrazyl free radicals including lipase, bile salt hydrolase activity with auto-aggregation and cell surface hydrophobicity was similarly observed. Results are proving the potentiality of E. durans F3, which can also be used as probiotic starter culture in dairy industries for manufacturing new products that imparts health benefits to the host. Finding the potent and novel probiotic strains will also satisfy the current developing market demand for probiotics.