• Korean Journal of Food Science and Technology
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• v.17 no.3
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• pp.192-196
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• 1985

Eight strains of Lactobacilli(a, b, b', c, d, e, f and g) were isolated from seven Korean liquid-yogurts(A, B, C, D, E, F and G), and identification and tolerance-test to digestive fluids were carried out. Isolate a from yogurt A and isolate a from yogurt E were identified as L. casei, isolate b from yogurt B as L. acidophilus, isolate d from yogurt D as L. bulgaricus, isolate f from yogurt F as L. helveticus, and isolate b' from yogurt B, isolate c from yogurt C and isolate g from yogurt G as L. jugurti, respectively. Isolate f(L. helveticus) and c(L. jugurti) showed high tolerance to artificial gastric juice but didn't to bile acid. Isolate b(L. acidophilus), a(L. casei), and e(L. casei) showed high tolerance to both artificial gastric juice and bile acid, but isolate d(L. bulgaricus), b'(L. jurgurti) and g(L. jugurti) did not.

• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.101-104
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• 1995

We isolated sixty lactic acid bacteria(LAB) from lactic fermented products. Among 60 isolates of LAB, 30 isolates were identified as Lactobacillus casei ssp.(5 strains), Lactobacillus acidophilus(2 strains), Lactobacillus delbrueckii ssp. bulgaricus(6 strains), Lactobacillus plantarum(4 strains), Streptococcus salivarius ssp. thermophilus(11 strains), and Streptococcus faecalis(2 strains). The acid tolerance and bile resistance of 30 LAB were determined. Because the acid tolerance was affected by the initial cell concentrations, the analysis of covariance could be used to remove the effect of initial cells on acid tolerance when testing for differences in acid tolerance among six species. Viability of LAB under acidic condition, pH 3 for 2 hours at $37^{\circ}C$, was significantly different among the species. L. casei and L. acidophilus strains showed great viability, but L. bulgaricus and S. thermophilus strains were very weak in acid tolerance.

• Microbiology and Biotechnology Letters
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• v.19 no.5
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• pp.429-432
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• 1991

In order to prepare probiotics, a strain which has resistant against acid, bile salts and antibiotics was isolated from infant and anirnat feces. Among these isolated strains, TK- 19 showed a strong acid tolerance and growth at 500 $\mu g$/ml of Na-deoxycholate. Also strain TK-19 was resistant to kanarnycin (30 $\mu g$/ml), streptomycin (10 $\mu g$/ml), nisin (50 $\mu g$/ml) and tetracycline (10 $\mu g$/ml). The isolated strain TK-19 was identified as Streptococcus faeciam, and was named Streptococcus faeciurn TK-19.

• Food Science of Animal Resources
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• v.24 no.2
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• pp.164-170
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• 2004

The purpose of this study is to isolate probiotic lactic acid bacteria (LAB) that produced bile salts hydrolase. One hundred twenty strains were initially isolated from human feces. Based on their resistance of acid, tolerances of bile salts, and inhibitory activity against Escherichia coli, five strains were selected. A strain producing highest activity of bile salts hydrolase was identified as Lactoacillus plantarum using API carbohydrate fermentation pattern and 16S rRNA sequences, and named CK102. Lactobacillus plantarum CK102 survived at a level of 1.36${\times}$10$\^$8/ CFU/$m\ell$ in pH 2 buffer for 6 h and showed exhibited excellent bile tolerance. When L plantarum CK102 was cultured with E. coli in MRS broth, no viable cells of E. coli was detected after 18 h fermentation. These results suggest that Lactobacillus plantarum CK 102 may be commercially used for the probiotic culture.

• Korean Journal of Microbiology
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• v.47 no.3
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• pp.231-240
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• 2011

The objective of this study was to evaluate the acid and bile tolerance, bile salt hydrolase (BSH) activity, and cholesterol assimilation ability of lactic acid bacteria isolated from mustard leaf kimchi. MLK11, MLK22, MLK27, MLK41, and MLK67 were relatively acid- and bile-tolerant strains, with more than $10^5$ CFU/ml after incubation in simulated gastric juice and intestinal fluid, while MLK53 was the most sensitive strain to acid and bile. Strains MLK22 and MLK67 deconjugated the highest level of sodium glycocholate with more than 3.5 mM of cholic acid released, while deconjugation was lowest by strains MLK13 and MLK41 which released only 1.35 mM and 1.16 mM, respectively. Specially, strains MLK22 and MLK67 showed higher deconjugation of sodium glycocholate compared to sodium taurocholate and conjugated bile mixture. Although strains MLK22 and MLK67 exhibited maximal BSH activity at the stationary phase, MLK22 had somewhat higher total BSH activity compared to MLK67 towards both sodium glycocholate and sodium taurocholate. Meanwhile, cholesterol removal varied among tested strains (p<0.05) and ranged from 5.22 to 39.16 ${\mu}g$/ml. Especially, MLK67 strain assimilated the highest level of cholesterol in media supplemented with 0.3% oxgall, cholic acid, and taurocholic acid (p<0.05). According to physiological and biological characteristics, pattern of carbohydrate fermentation, and 16S rDNA sequence, strain MLK67 that may be considered as probiotic strain due to acid and bile tolerance and cholesterol-lowering effects was identified as Pediococcus pentosaceus MLK67.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.201.1-201
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• 2003

생균제로서 가능성 있는 유산균의 선별을 위해 발효식품인 동치미로부터 분리된 균주들의 내산성, 내담즙성, 내췌장액성 및 유해균 억제능을 조사하였다. 특히 분리된 균종 중에서 FF-3가 인공위액과 담즙산에 대한 높은 내성을 나타내었을 뿐만 아니라, Salmonella sp. 과 Escherichia coli에 대하여 높은 항균 활성을 나타내었다. FF-3유래 박테리오신은 그람양성 및 음성 세균에서 넓은 항균 범위를 나타내었다. 본 연구에서 최종선별된 FF-3 균주를 16s rDNA sequence 동정한 결과 Lactobacillus sp.으로 확인되어 FF-3으로 명명하였다.

• Korean Journal of Microbiology
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• v.49 no.3
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• pp.275-281
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• 2013

Probiotics have been reported to benefit human health by modulating immunity, lowering cholesterol, improving lactose tolerance, and preventing some cancer. Once ingested, probiotic microorganisms have to survive harsh conditions such as low pH, protease-rich condition, and bile salts during their passage through the gastro-intestinal (GI) tract colonize and proliferate to exert their probiotic effects. The dual coating technology, by which the bacteria are doubly coated with peptides and polysaccharides in consecutive order, was developed to protect the ingested bacteria from the harsh conditions. The aim of the study was to evaluate the viable stability of a doubly coated blend of four species of Bifidobacterium by comparing its bile/acid resistance and heat viability in vitro with that of the non-coated blend. After challenges with acid, bile salts, heat, and viable cell counts (VVCs) of the dual coated and non-coated blend were determined by cultivation on agar plates or flow cytometric measurement after being stain with the BacLigtht kit$^{TM}$. The results showed that the dual coated blend was much higher resistant to the acidic or bile salt condition than the non-coated blend and heat viability was also higher, indicating that the dual coating can improve the survival of probiotic bacteria during their transit through the GI tract after consumption.

• Journal of Dairy Science and Biotechnology
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• v.30 no.1
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• pp.45-53
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• 2012

Lactobacillus acidophilus isolated from the feces of a 7-day-old breast-fed infant was characterized to examine the scope of its commercial use. Forty-three Lactobacillus strains, which could grow at pH 5.5, were isolated. From these Lactobacillus isolates, 14 Lactobacillus strains were selected, which demonstrated more than 80% viability and homofermentative lactic fermentation. Finally, 9 L. acidophilus strains (NB 201~NB 209) were identified as candidate strains based upon biochemical properties, carbohydrate utilization, and cellular fatty acid composition. L. acidophilus isolates demonstrated a survival rate of more than 80% when exposed to pH 2.5 for 2 h. In particular, L. acidophilus NB 204 showed a strong acid tolerance, with a 71% survival rate even at pH 2.0. L. acidophilus isolates also manifested high bile acid tolerance; more than 87% of the cells survived on agar containing 1% bile extract, except for L. acidophilus NB 206, which showed a 73% survival rate. All L. acidophilus isolates were confirmed to have proteolytic activity; L. acidophilus NB 204 and NB 209 yielded higher levels of TCA-soluble peptides and free amino acids. The ${\beta}$-galactosidase activity of the L. acidophilus isolates was in the range of 1.97~2.45 units/mL.

• Food Science and Preservation
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• v.10 no.3
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• pp.406-410
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• 2003

For selection of lactic acid bacteria for probiotics, we have examined isolated strains from Korean Dongchimi to assess the acid, bile, and pancreatic tolerance and the growth inhibition on the pathogens. Especially, a kind of isolated strains, FF-3 showed the highest resistancy to both of HCl and bile salt, as well as the highest inhibitory activities against Salmonella sp. and Escherichia coli. Further the bacteriocin of FF-3 showed relatively wide range of inhibition spectrum against gram positive and some gram negative bacterias. By using 16s rDNA sequencing method, FF-3 of the selected lactic acid bacteria were found to be identified as genus Lactobacillus.

• Korean Journal of Microbiology
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• v.46 no.1
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• pp.9-14
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• 2010

In this study, lactic acid bacteria with high angiotensin converting enzyme inhibitor activity were isolated from Korean fermented food, such as kimchi and salted seafood. The strain HLJ59, isolated from salted shrimp showed the highest angiotensin converting enzyme inhibitor activity in DeMan Rogosa Sharpe broth. Optimum growth temperature of Lactobacillus brevis HLJ59 was at $34^{\circ}C$. Acid treatment at pH 3.0 for 1.5 h decreased cell viability from $9.9{\times}10^8$ CFU/ml to $3.11{\times}10^4$ CFU/ml. The bile extract concentration of 0.3%, 0.5%, and 1.0% in MRS broth did not inhibit the growth of HLJ59. Isolated strain HLJ59 showed more sensibility to amikacin, gentamycin, neomycin, streptomycin, kanamycin, cefmetazole, cephalothin, ampicillin, ticarcillin, sulbactam+ampicillin, amoxicillin+clavulanic acid (AMC), tetracycline, and sulfamethoxazole+trime thoprim (SXT) as compare to other 7 different antibiotics. However, it showed more resistance to cefoxatin, ceftnaxone, penicillin, ciprofloxacin, nalidixic acid, lincomycin, and chloramphenicol.