• Journal of Microbiology and Biotechnology
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• 제3권3호
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• pp.199-203
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• 1993

The bacteriocin produced by Pediococcus acidilactici KFRI 168 exhibited a wide antimicrobial spectrum including many strains of lactic acid bacteria, Listeria monocytogenes, Staphylococcus aureus, and Enterococcus faecium by both disk and deferred assay methods. Inhibition of Lis. monocytogenes and Stph. aureus were observed only from deferred assay. Gram-negative bacteria were not inhibited. Bacteriocin production was observed at 10 h, and was maximized at 16 h in MRS broth incubated at $37^{\circ}C$. In a beaker sausage fermented with P. acidilactici KFRI 168, viable counts of Stph. aureus, Salmonella, Escherichia coli, Clostridium perfringens, and Lis. monocytogenes were reduced by 2.8, 2.3, 2.4, 0.7, and 0.5 log CFU/g, respectively. Inoculated P. acidilactici KFRI 168 maintained its viable count of more than $10^8$ CFU/g during the whole fermentation period, and it took less than 8 h to reduce sausage pH below 5.

• 한국식품영양과학회지
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• 제27권3호
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• pp.455-460
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• 1998

This study was carried out to investigate antimicrobial activities of ethanol extracts from 12 kinds of spices against Lactobacillus plantarum and Leuconostoc mesenteroides to kimchi fermentation. Lactic acid bacteria were isolated from fermenting kimchi, were identified as Leu. mesenteroides, Lac. sake, Lac. plantarum and Pediococcus pentosaceus. The ethanol extracts of cardamon, thyme and cumin among 12 spices showed antimicrobial activities against Lac. plantarum, while they did not showed the activites against Leu. mesenteroides through paper disc method. In addition, the growth of Lac. plantarum was inhibited in MRS broth containing each of cardamon(>4%), thyme(>4%) an cumin(>1%).

• Food Science and Biotechnology
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• 제16권4호
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• pp.580-583
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• 2007

Phytase activity was examined with various bifidobacterial strains cultured statically in MRS broth at $37^{\circ}C$ for 48 hr. Seven Bifidobacterium species showed mostly an intracellular phytase activity, though their specific activities were very low. The highest specific activity was found in Bifidobacterium animalis B33 strain, among 7 bifidobacteria tested. The specific activity was highest during the exponential growth phase. Carbohydrates and the concentration of phosphorus sources had an effect on the phytase activity and bacterial growth. Glucose was the most favorable carbohydrate for the phytase activity. Phytate inhibited the cell growth, and phytase activity decreased with increase of phytate concentration. The phytase activity was even higher in the static microaerophilic growth than that in anaerobic state, despite the stimulated growth in anaerobic growth. The optimal pH ranges were comparatively broad, but the optimal temperatures were $50^{\circ}C$ for all tested strains. The phytase activity was most active at pH 6.5 and $50^{\circ}C$ for B. animalis B33 strain.

• 한국축산식품학회지
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• 제37권1호
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• pp.147-152
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• 2017

A bioluminescent Lactobacillus plantarum (pLuc2) strain was constructed. The luminescent signal started to increase during the early exponential phase and reached its maximum in the mid-exponential phase in a batch culture of the strain. The signal detection sensitivity of the strain was the highest in PBS (phosphate buffered saline), followed by milk and MRS broth, indicating that the sensitivity was influenced by the matrix effect. The strain was used in millet seed fermentation which has a complex matrix and native lactic acid bacteria (LAB). The luminescent signal was gradually increased until 9 h during fermentation and abolished at 24 h, indicating that the strain could be specifically tracked in the complex matrix and microflora. Therefore, the bioluminescent labeling system can be used for monitoring LAB in food and dairy sciences and industries.

• Food Science and Biotechnology
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• 제15권1호
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• pp.86-90
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• 2006

Two lactic acid bacteria (LAB) with high ${\gamma}$-aminobutyric acid (GABA)-producing capacity were isolated from naturally aged cheese. Examination of the biochemical features using an API kit indicated that the two strains belonged to Lactobacillus. They were gram positive, rod-type bacteria, and fermented arabinose, melezitose, melibiose and xylose, but did not utilize cellobiose or trehalose. 16S rDNA sequencing analysis confirmed that they were Lactobacillus buchneri and Lactobacillus sp. They were accordingly named as Lactobacillus buchneri OPM-1 and Lactobacillus sp. OPM-2, and could produce GABA from MRS broth supplemented with 10 g/L of monosodium glutamate (MSG) at a productivity of 91.7 and 116.7 mg/L/hr, respectively. Cell extracts of L. buchneri OPM-1 and Lactobacillus sp. OPM-2 showed glutamate decarboxylase (GAD) activity, for which the optimum pH and temperature were 5.5 and $30^{\circ}C$, respectively.

• Food Science and Biotechnology
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• 제18권3호
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• pp.749-754
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• 2009

The polysaccharide (BB-pol) extracted from Bifidobacterium bifidum BGN4 showed growth inhibitory effects on several colon cancer cell lines such as HT-29 and HCT-116. To increase the yield of polysaccharide, B. bifidum BGN4 was cultured in various culture media with different compositions. When B. bifidum BGN4 was cultured in modified MRS broth containing phytic acid, the cells showed increased branch formation and enlarged morphology. The content of total carbohydrate and the ability of adhesion to intestinal epithelial cells were also increased by phytic acid. The polysaccharide obtained from the cells grown in the presence of phytic acid inhibited the proliferation of cancer cell lines such as HT-29 and MCF-7 cells but not normal colon cell line, FHC. Taken together, Bifidobacterium grown in the presence of phytic acid may confer enhanced beneficial function for the host.

• Journal of Microbiology
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• 제39권2호
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• pp.146-148
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• 2001

Lactobacillus crispatus ATCC 33820 and L. gasseri ATCC 33323 were grown in MRS broth (pH 6.5) at 37$^{\circ}C$ for 24 h and the antibacterial activities of cell free culture supernatants were determined by the agar well diffusion method. The culture supernatants were inhibitory to Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Enterococcus faecalis, Pediococcus acidilacticii, and Lactobacillus helveticus. The supernatants did not show any lysozyme activity. Addition of catalase did not affect the antibacterial activities of the supernatants. The antibacterial substances were heat stable (100$^{\circ}C$ for 60 min) and sensitive to proteases.

• 한국축산식품학회:학술대회논문집
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• 한국축산식품학회 2004년도 정기총회 및 제33차 춘계 학술대회
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• pp.89-119
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• 2004

This study was conducted to isolate lactobacilli having probiotic characteristics to be used as health adjuncts with fermented milk products. Acid tolerant strains were selected in Lactobacilli MRS broth adjusted to pH 4.0 from 80 healthy persons (infants, children and adults). And bile tolerant strains were examined in Lactobacilli MRS broth in which 1.0% bile salt was added. By estimation above characteristics, the strains No. 27, which was isolated from adult feces, was selected and identified as Lactobacillus salivarius subsp. salivarius based on carbohydrate fermentation and 16S rDNA sequencing. It was used as a probiotic strain in fermented milk products. The pH of fermented milk decreased from pH 6.7 to 5.0 and titratable acidity increased from 0.3% to 1.0% by L. salivarius subsp. salivarius (isolation strain 20, 35, and 37), when incubated for 36 h at $37^{\circ}C$. The number of viable cell counts of fermented milk was maximized at this incubation condition. The SDS-PAGE evidenced no significant change of casein but distinct changes of whey protein were observed by isolated L. salivarius subsp. salivarius for titratable acidity being incubated by $0.9{\sim}1.0%$ at $37^{\circ}C$. All of the strains produced 83.43 to 131.96 mM of lactic acid and 5.39 to 26.85 mM of isobutyric acid in fermented products. The in vitro culture experiment was performed to evaluate ability to reduce cholesterol levels and antimicrobial activity in the growth medium. The selected L. salivarius subsp. salivarius reduced $23{\sim}38%$ of cholesterol content in lactobacilli MRS broth during bacterial growth for 24 hours at $37^{\circ}C$. All of the isolated L. salivarius subsp. salivarius had an excellent antibacterial activity with $15{\sim}25$ mm of inhibition zone to E. coli KCTC1039, S. enteritidis KCCM3313, S. typhimurium M-15, and S. typhimurium KCCM40253 when its pH had not been adjusted. Also, all of the isolated L. salivarius subsp. salivarius had partial inhibition zone to E. coli KCTC1039, E. coli KCTC0115 and S. enteritidis KCCM3313 when it had been adjusted to pH 5.7. The selected strains were determined to have resistances of twelve antibiotic. Strains 27 and 35 among the L. salivarius subsp. salivarius showed the highest resistance to the antibiotics. Purified ${\alpha}$-galactosidase was obtained by DEAE-Sephadex A-50 ion exchange chromatography, Mono-Q ion exchange chromatography and HPLC column chromatography from L. salivarius subsp. salivarius 27. The specific activity of the purified enzyme was 8,994 units/mg protein, representing an 17.09 folds purification of the original cell crude extract. The molecular weight of enzyme was identified about 53,000 dalton by 12% SDS-PAGE. Optimal temperature and pH for activity of this enzyme were $40^{\circ}C$ and 7.0 respectively. The enzyme was found to be stable between 25 and $50^{\circ}C$. ${\alpha}$-galactosidase activity was lost rapidly below pH 5.0 and above pH 9.0. This enzyme was liberated galactose from melibiose, raffinose, and stachyose, and also the hydrolysis rate of substrate was compound by HPLC. These results indicated that some of the L. salivarius subsp. salivarius (strain 27 and 35) are considered as effective probiotic strains with a potential for industrial applications, but the further study is needed to establish their use as probiotics in vivo.

• 한국축산식품학회지
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• 제24권2호
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• pp.164-170
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• 2004

건강한 성인의 분변으로부터 담즙산 분해능이 우수한 젖산균의 분리를 위하여 무작위 선별법과 도말법을 사용하여 층 120주의 젖산균을 1차 분리하였고, 그중 5종의 젖산균을 최종 선발하였다. 유용한 젖산균이 갖추어야할 중요한 성질인 내산성, 내담즙산성, 대장균 저해능을 시험한 결과 Lactobacillus sp. CK 102이 가장 우수한 균주로 나타났다. Lactobacillus sp. CK 102 균주는 pH 2.0에서 68％ 이상의 내성과 1.0％ 담즙산이 함유된 배지에서 90％이상의 내성을 나타냈으며 MRS 배지에서 대장균과 혼합 배양시 18시간 이내에 대장균을 100％ 사멸시켰다. 젖산균제로써 기능이 가장 우수한 균주인 Lactobacillus sp. CK 102를 API kit와 16S rRNA sequencing 방법을 사용하여 동정한 결과 Lactobacillus platarum 으로 밝혀졌다. 이상의 결과에서 분리한 Lactobacillus sp. CK 102는 생균제로서 안전하게 이용할 수 있는 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제22권4호
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• pp.516-525
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• 2012

LAB were isolated from makgeolli locally produced around Jinju, Gyeongnam, S. Korea during spring of 2011. Randomly selected 11 isolates from MRS agar plates were identified first by API CHL 50 kits and then 16S rRNA gene sequencing. All 11 isolates were identified as Lactobacillus plantarum. Among them, ST4 grew in MRS broth with ethanol up to 10%, showing the highest alcohol resistance. L. plantarum ST4 was moderately resistant against acid and bile salts. When cellular proteins of L. plantarum ST4 under ethanol stress were analyzed by two-dimensional gel electrophoresis (2DE), the intensities of 6 spots increased, whereas 22 spots decreased at least 2-fold. Those 28 spots were identified by peptide mass fingerprinting (PMF). FusA2 (elongation factor G) increased 18.8-fold (6% ethanol) compared with control. Other proteins were AtpD (ATP synthase subunit beta), DnaK, GroEL, Tuf (elongation factor Tu), and Npr2 (NADH peroxidase), respectively. Among the 22 proteins decreased in intensities, lactate dehydrogenases (LdhD and LdhL1) were included.