• Asian-Australasian Journal of Animal Sciences
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• 제15권12호
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• pp.1790-1797
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• 2002

Lactic acid bacteria were isolated from piglets and chicken and characterized. Lactic acid bacteria showing resistance to low pH and bile, adhesion to intestinal epithelium cells, and the inhibition of Escherichia coli and Salmonella spp. were identified as Lactobacillus acidophilus. L. acidophilus PF01 survived for 2 h in MRS broth adjusted to pH 2. L. acidophilus CF07 was less resistant than L. acidophilus PF01 to pH 2, but survived at pH 2.5 for 2 h. Both of isolates were able to grow in MRS broth containing 0.3% (w/v) bile, with L. acidophilus CF07 being more tolerant to bile than L. acidophilus PF01. L. acidophilus PF01 and CF07 adhered specifically to the duodenal and jejunal epithelium cells of piglet, and the cecal and duodenal epithelium cells of chicken, respectively. Both of isolates did not adhere to the epithelium cells of the various animal intestines from which they were isolated. When L. acidophilus was cultured with E. coli and Salmonella spp. in MRS broth, MRS broth containing 2% skim milk powder or modified tryptic soy broth at $37^{\circ}C$, L. acidophilus PF01 and CF07 inhibited the growths of E. coli K88 and K99, and S. enteritidis and S. typhimurium, respectively. Both of isolates were found to possess the essential characteristics of probiotic lactic acid bacteria for piglet and chicken.

• 한국미생물·생명공학회지
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• 제41권4호
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• pp.442-448
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• 2013

김치, 막걸리 및 시판되는 누룩으로부터 젖산균을 분리한 후 다양한 농도의 알코올을 함유한 MRS 배지에서 배양하여 생육 여부를 조사하였다. 알코올이 13%(v/v) 포함된 MRS 배지에서 $OD_{600}$ 값이 가장 높이 증가한 젖산균 2종을 최종 선별하였고 이 두 균주의 16S rRNA 유전자 염기서열분석 및 API kit를 이용한 생화학적 동정을 실시한 결과 두 종 모두 P. acidilactici에 가까운 종인 것을 확인하여 P. acidilactici K3와 P. acidilactici S1으로 명명하였다. 선별한 P. acidilactici K3와 S1의 bacteriocin 생성 여부를 확인한 결과 식중독균인 S. aureus의 생육 저해를 일으키는 bacteriocin 생성 능력이 있음을 확인하였다. 선별한 두 균주와 표준 균주(P. acidilactici DSM 20284)의 알코올 내성을 비교한 결과 6% 이하의 저농도 알코올이 포함된 배지에서는 균주 생육에 큰 차이가 없었으나 12% 이상의 알코올이 포함된 배지에서는 표준 균주보다 최대 3배 이상 알코올 내성이 뛰어남을 확인하였다. 알코올 내성 균주 P. acidilactici K3와 S1을 살균 막걸리에 첨가한 후 냉장 온도($4^{\circ}C$와 $10^{\circ}C$)에서 저장하며 생균수를 측정한 결과 사멸하지 않고 한 달 간 생균수가 유지됨을 확인하였다.

• Journal of Plant Biology
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• 제32권3호
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• pp.137-144
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• 1989

In order to clarify the effect of the associative nitrogen fixing bacteria on the growth of corn(Zea mays L. Suwon19), we inoculated corn seedlings with Azospirillum amazonense Y1, a micro-aerobic and acid-tolerant nitrogen fixer, and analyzed the growth and dry matter production and changes of nitrogen and phosphorus quantity of the plant during the growing period. The inoculation of associative N-fixing bacgteria increased the growth of height, leaf area, dry weight and total nitrogen quantity of the plant by 15.4%, 65.4%, 33.7% and 38.0%, respectively, on the day of 56th after sowing. Especially the inoculation of A. amazonense Y1 showed two to three-fold accumulation of phosphorus in each organ of plant. The associative bacteria accelerated the growth of the under ground parts more than those of the upper ground parts of corn plant, and caused decrease in T/R ratios.

• 한국식품저장유통학회지
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• 제1권1호
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• pp.21-27
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• 1994

For the purpose of improving microbiolgical quality of carrot powder, which is being used as minor ingredients of convenience foods, comparative influence of Υ-irradiation and ethylene oxide(E.O) fumigation was investigated with emphasis on sterilizating effect and physicochemical propertied Carrot powder sample was contaminated with thermophiles 4.0$\times$103/g, acid tolerant bacteria 3.7$\times$103/g and coliforms 1.6$\times$102/g, respectively. And thus sanitation process was required. E.O fumigation in commercial practice was not enough to destroy thermophilic bacteria, while Υ-irradiation at below 5 kGy could reduce all microorganisms up to undectected levels. Radiosensitivity(D10) of thermophiles was shown to be 2.25 kGy. The applicable dose of irradiation to the improvement of microbiological quality showed insignificant influences on the physicochemical quality of the sample.

• 한국축산식품학회지
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• 제34권1호
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• pp.106-114
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• 2014

Folic acid, one of the B group of vitamins, is an essential substance for maintaining the functions of the nervous system, and is also known to decrease the level of homocysteine in plasma. Homocysteine influences the lowering of the cognitive function in humans, and especially in elderly people. In order to determine the strains with a strong capacity to produce folic acid, 190 bacteria were isolated from various kinds of jeotgal and chungkuk-jang. In our test experiment, JA71 was found to contain $9.03{\mu}g/mL$ of folic acid after 24 h of incubation in an MRS broth. This showed that JA71 has the highest folic acid production ability compared to the other lactic acid bacteria that were isolated. JA71 was identified as Lactobacillus plantarum by the result of API carbohydrate fermentation pattern and 16s rDNA sequence. JA71 was investigated for its physiological characteristics. The optimum growth temperature of JA71 was $37^{\circ}C$, and the cultures took 12 h to reach pH 4.4. JA71 proved more sensitive to bacitracin when compared with fifteen different antibiotics, and showed most resistance to neomycin and vancomycin. Moreover, it was comparatively tolerant of bile juice and acid, and displayed resistance to Escherichia coli, Salmonella Typhimurium, and Staphylococcus aureus with restraint rates of 60.4%, 96.7%, and 76.2%, respectively. These results demonstrate that JA71 could be an excellent strain for application to functional products.

• 한국미생물·생명공학회지
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• 제43권3호
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• pp.219-226
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• 2015

경남 남해군에서 전통방식으로 제조한 식초에서 초산균들을 분리하였다. 분리균주들은 그램 음성, 비운동성, 단간균으로 이중 선발된 3 균주는 16S rRNA 유전자 염기서열 분석 결과 Acetobacter pasteurianus 혹은 Acetobacter aceti로 동정되었다. A. pasteurianus NH2와 A. pasteurianus NH6는 ethanol, glycerol, D-fructose, D-glucose, D-mannitol, D-sorbitol, L-glutamic acid, 그리고 Na-acetate를이용하였다. A. aceti NH12는 ethanol, n-propanol, glycerol, D-mannitol과 Na-acetate를이용하였다. 이들은 30℃, 초기 pH 3.4에서가장 잘 자랐고 초기 초산농도 3% (v/v)까지는 생육하였다. 초산 생산을 위한 최적 조건은 30℃, pH 3.4, 초기 ethanol 농도 5%로 이 경우 초산을 7.3−7.7% 생성하였다.

• Food Science and Biotechnology
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• 제17권2호
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• pp.402-407
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• 2008

The synergistic antimicrobial effect of Achyranthes japonica Nakai (AJN) and Bifidobacterium extracellular factors against Clostridium difficile were measured using a turbidity method. Each broth supernatant of Bifidobacterium infantis ($68.8{\pm}0.02%$) and Bifidobacterium adolescentis ($33.2{\pm}0.2%$) obtained by adding ethyl acetate soluble fractionate from A. japonica Nakai ethanolic extracts (AJNEA, 100 ppm, no inhibition) showed high synergistic antimicrobial activity against C. difficile. In addition, the antimicrobial activity in a laboratory medium and yogurt products against C. difficile were evaluated. In yogurt prepared with a starter 5 (Lactobacillus acidophilus: Streptococcus thermophilus: B. adolescentis =1 : 1 : 1) and a starter 4 (L. acidophilus: S. thermophilus: B. infantis=1 : 1 : 1) and 0.5% AJNEA powder, high antimicrobial effects were recorded that measured 79.0 and 65.2%, respectively. The results indicated the potential of AJN extract for use as an antimicrobial agent. In addition, the efficiency of the antimicrobial activity of the extracts was further improved in combination with lactic acid bacteria, which suggests that they have the potential to be used as a highly effective antibiotic-tolerant microorganism prevention system. Such a strategy can be used for alternative drugs or functional food additives for treatment of antibiotic-associated diarrhea.

• 한국식품위생안전성학회지
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• 제1권1호
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• pp.39-46
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• 1986

Comparison of ethylene oxide(E.O) fumigation and gamma irradiation on the sterilization, microbiological, physicochemcial and sensory quality of dried fishery products (shucked shellfish and mussel powder) were investigated. The viable cell count of mesophilic total bacterial was reduced by over 2 to 3 log cycles with irradiation of 3 to 5 kGy, and those samples were completely sterilized by irradiation dose of 7 to 10 kGy. In view of reduction of microorganisms, D10 value of each samples were ranged from 1. 36-1. 46 kGy. fungi, mesophilic spores, acid tolerant bacteria and coliforms were sterilized at 5 to 7 kGy irradiation but E.O. fumigation proved insulfficient to eliminate the mesophilic total bacteria and fungi. In the physicochemical and sensory quality of samples, such as the amino acid, TBA value, TMA-N, color difference and overall acceptability irradiated sample with optimum dose was similar to those of the nonirradiated sample, while E.O. fumigated sample was remarkably deteriorated in the physicochemical and sensory quality of samples.

• Journal of Microbiology and Biotechnology
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• 제32권6호
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• pp.783-791
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• 2022

Gamma-aminobutyric acid (GABA) improves various physiological illnesses, including diabetes, hypertension, depression, memory lapse, and insomnia in humans. Therefore, interest in the commercial production of GABA is steadily increasing. Lactic acid bacteria (LAB) have widely been reported as a GABA producer and are safe for human consumption. In this study, GABA-producing LAB were preliminarily identified and quantified via GABase assay. The acid and bile tolerance of the L. plantarum FBT215 strain were evaluated. The one-factor-at-a-time (OFAT) strategy was applied to determine the optimal conditions for GABA production using HPLC. Response surface methodology (RSM) with Box-Behnken design was used to predict the optimum GABA production. The strain FBT215 was shown to be acid and bile tolerant. The optimization of GABA production via the OFAT strategy resulted in an average GABA concentration of 1688.65 ± 14.29 ㎍/ml, while it was 1812.16 ± 23.16 ㎍/ml when RSM was applied. In conclusion, this study provides the optimum culture conditions for GABA production by the strain FBT215 and indicates that L. plantarum FBT215 is potentially promising for commercial functional probiotics with health claims.

• Journal of Microbiology and Biotechnology
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• 제24권7호
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• pp.987-997
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• 2014

The mature landfill leachate, which is characterized by a high concentration of ammonia nitrogen ($NH_3$-N) and humic acid (HA), poses a challenge to biotreatment methods, due to the constituent toxicity and low biodegradable fraction of the organics. In this study, we applied bioaugmentation technology in landfill leachate degradation by introducing a domesticated $NH_3$-N and HA resistant bacteria strain, which was identified as Bacillus cereus (abbreviated as B. cereus Jlu) and Enterococcus casseliflavus (abbreviated as E. casseliflavus Jlu), respectively. The isolated strains exhibited excellent tolerant ability for $NH_3$-N and HA and they could also greatly improved the COD (chemical oxygen demand), $NH_3$-N and HA removal rate, and efficiency of bioaugmentation degradation of landfill leachate. Only 3 days was required for the domesticated bacteria to remove about 70.0% COD, compared with 9 days' degradation for the undomesticated (autochthonous) bacteria to obtain a similar removal rate. An orthogonal array was then used to further improve the COD and $NH_3$-N removal rate. Under the optimum condition, the COD removal rate in leachate by using E. casseliflavus Jlu and B. cereus Jlu increased to 86.0% and 90.0%, respectively after, 2 days of degradation. The simultaneous removal of $NH_3$-N and HA with more than 50% and 40% removal rate in leachate by employing the sole screened strain was first observed.