• 한국식품조리과학회지
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• 제22권3호통권93호
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• pp.291-298
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• 2006

B. subtilis NRLSI IV 균주를 이용하여 포자농도와 발효온도를 달리하여 제조한 청국장의 생균수, 이화학적 특성 및 관능적 특성의 결과는 다음과 같다. 포자농도별$(10^2,\;10^4,\;10^6,\;10^8\;CFU/mL)$로 제조한 청국장에서, 생균수, 환원당 및 아미노태질소는 $10^6\;CFU/mL$ 농도에서 가장 높은 반면, 기능성 물질로 밝혀진 점질물의 상대점도와 경도는 $10^2\;CFU/mL$ 농도에서 가장 높았다. 청국장의 이취 물질인 암모니아태 질소는 포자농도가 높아짐에 따라 급격히 증가하였다. 청국장의 관능검사 결과 $10^2\;CFU/mL$ 농도에서 외관, 색상, 청국장 맛 및 점질물의 점도에서 가장 높은 점수를 나타냈으며 이취는 가장 낮았다. 따라서 암모니아태 질소 함량이 낮고 상대점도 및 관능검사 결과가 우수한 조건의 청국장을 제조하기 위한 포자농도로 $10^2\;CFU/mL$가 적정한 것으로 사료되었다. 적정 포자농도인 $10^2\;CFU/mL$를 접종하여 발효온도별$(30,\;35,\;40,\;45^{\circ}C)$로 제조한 청국장의 특성을 살펴보면, $40^{\circ}C$에서 발효시킨 청국장의 생균수가 가장 많았고 $45^{\circ}C$에서 가장 적었다. 환원당 함량의 경우 발효온도가 높을수록 약간 증가하였으나 $30-40^{\circ}C$에서는 유의적인 차이를 보이지 않았다. 아미노태 질소 함량은 발효온도가 $30^{\circ}C$일 때 가장 높았고 $45^{\circ}C$는 $30^{\circ}C$에 비해 약 2.5배 낮은 함량을 보였고 암모니아태 질소 함량은 발효온도가 높을수록 감소하였다. 청국장의 관능검사 결과, 외관은 발효온도가 높을수록 높은 점수를 보였고, 균 형성 정도, 점질물의 점도 및 청국장 맛에서는 $40^{\circ}C$에서 가장 높은 점수를 나타냈으며 이취는 가장 낮았다. 청국장의 이화학적 특성, 상대점도 및 관능검사 결과에 의하여, 포자농도 $10^2\;CFU/mL$를 접종하여 청국장을 제조할 경우 $40^{\circ}C$에서 발효하는 것이 적정한 것으로 사료된다.

• 환경위생공학
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• 제12권1호
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• pp.85-95
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• 1997

Behavior of Listeria monocytogenes in Skim milk during fermentation by Lactobacillus bulgaricus YI-2 and Streptococcus lactis FYI-1 were determined. Autoclaved skim milk was inoculated with ca. 10$^{3}$ L. monocytogenes (Strain LM91-1 or LM 96-2) cells/ml, and with 5.0, 1.0, 0.5 or 0.1% of a milk culture of either L. bulgaricus TI-2 or S. lactis FYI-1. Skim milk containing ca. 10$^{3}$ L. monocytogenes was incubated at 37 or 42$\circ $C for 15 h with L. bulgaricus YI-2, and at 21 or 30$\circ $C for 15 h with S. lactis FYI-1. Cultured skim milks were stored at 4$\circ $C in the refrigerater. Samples were plated on Oxford Agar with oxford antimicrobic supplement to enumerate L. monocytogenes and on either modified MRS agar to enumerate lactic acid bacteria. L. monocytogenes survived the 15-h fermentation with S. lactis FYI-1 in all combinations of level of inoculum and temperature of incubation, but inhibition of growth ranged from 94 to 100%. When incubated with over the 1.0% of L. bulgaricus, L. monocytogenes inhibited or disappeared in fermented skim milk from 9 h after incubation. Especially, incubation at 42$\circ $C with 5.0% L. bulgaricus YI-2 as inoculum appeared to be the most effective inhibitory combination for strain LM 91-1, causing 100% inhibition in growth based on maximum papulation attained. In most instances of incubated with L. bulgaricus YI-2, growth of the pathogene appeared to be completely inhibited when the pH dropped below 4.38.

• 한국식품위생안전성학회지
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• 제13권1호
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• pp.1-5
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• 1998

본 연구는 E. coli O157:H7에 대한 LP system(lactoperoxidae/thiocyanate/hydrogen peroxide)의 항균효과를 측정하기 위해 수행되었다. 초기 접종수준($10^{2},\;10^{4},\;10^{7}cfu/ml$), LP의 농도 (10ppm, 20ppm, 30ppm), 배지종류 (TSB, UHT milk, raw milk), 배양온도 ($5^{\circ}C,\;10^{\circ}C,\;15^{\circ}C$) 등에 따라 E. coli O157:H7에 대한 항균효과를 측정, 비교한 결과, 초기 접종수준을 $10^2/ml$으로 하였을 때와 LP의 농도를 10ppm 및 $5^{\circ}C$ 배양에서 항균력이 가장 높게 나타났다.

• The Plant Pathology Journal
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• 제28권2호
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• pp.172-184
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• 2012

An infection risk model for Phytophthora blight on chili pepper was developed to estimate the first date of disease occurrence in the field. The model consisted of three parts including estimation of zoosporangium formation, soil water content, and amount of active inoculum in soil. Daily weather data on air temperature, relative humidity and rainfall, and the soil texture data of local areas were used to estimate infection risk level that was quantified as the accumulated amount of active inoculum during the prior three days. Based on the analysis on 190 sets of weather and disease data, it was found that the threshold infection risk of 224 could be an appropriate criterion for determining the primary infection date. The 95% confidence interval for the difference between the estimated date of primary infection and the observed date of first disease occurrence was $8{\pm}3$ days. In the model validation tests, the observed dates of first disease occurrence were within the 95% confidence intervals of the estimated dates in the five out of six cases. The sensitivity analyses suggested that the model was more responsive to temperature and soil texture than relative humidity, rainfall, and transplanting date. The infection risk model could be implemented in practice to control Phytophthora blight in chili pepper fields.

• 한국식품위생안전성학회지
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• 제13권2호
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• pp.83-86
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• 1998

본 연구의 목적은 L. monocytogenes에 대한 LP system의 항균효과를 측정하기 위하여 수행되었다. 초기 접종수준($10^{2},\;10^{4},\;10^{7}\;CFU/ml$), LP의 농도는 (10, 20, 30ppm), 그리고 저장온도(5, 10, $15^{\circ}C$), 배지종류(TSB-YE, UHT milk) 에 따라 Listeria monocytogenes에 대한 항균 효과를 측정 비교한 결과 초기접종수준을 $10^{2}\;cfu/ml$로 하였을때와 LPshd도는 10ppm 및 $5^{\circ}C$로 배양에서 항균력이 높게 나타났다. UHT milk를 이용한 LP system의 항균 효과는 Tryptic soy agar를 이용한 시험결과와 비슷하게 나타났다.

• Korean Chemical Engineering Research
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• 제54권1호
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• pp.140-144
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• 2016

본 연구에서는 극지 연구소로부터 분양 받은 Arthrobacter sp. PAMC 27388 균주에서 생산되는 아밀라아제(amylase)를 물리적 요인(physical factor)들의 변화를 통하여 생산배지 최적화를 수행하였다. 한천 배지 상에서 lugol solution을 이용한 클린환의 확인을 통하여 아밀라아제가 생산됨을 확인하였으며, 16S rDNA를 이용하여 동정한 결과 Arthrobacter sp. 임을 확인할 수 있었다. 최적화 이전의 아밀라아제 생산량은 1.66 mU/L로 확인되었다. 최적화 결과, 2.49 mL의 접종부피, pH 6.85, 42.87 mL의 배지 부피의 조건에서 가장 많은 양의 아밀라아제가 생산될 것으로 예상되었으며, 생산량은 2.84 mU/L로 예상되었다. 확인 실험을 통하여 최적화 이전과 비교하여 생산량이 약 150% 증가한 2.50 mU/L의 아밀라아제가 생산됨을 확인할 수 있었다.

• 한국작물학회지
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• 제57권4호
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• pp.389-396
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• 2012

Melon (Cucumis melo) is an annual herbaceous plant of the family Cucurbitaceae. Phytophthora rot, caused by Phytophthora capsici is a serious threat to cucurbits crops production as it directly infects the host plant, and it is difficult to control because of variable pathogenicity. This study investigated the resistance of 450 accessions of melon germplasm against Phytophthora rot by inoculating the seedlings with sporangial suspension ($10^{5\;or\;6}$ zoosporangia/ml) of P. capsici. Disease incidence of Phytophthora rot was observed on the melon germplasm at 7-day intervals for 35 days after inoculation. Susceptible melon germplasm showed either severe symptoms of stem and root rot or death of the whole plant. Twenty out of 450 tested accessions showed less than 20% disease incidence, of which five accessions showed a high level of resistance against Phytopthtora rot. Five resistant accessions, namely IT119813, IT138016, IT174911, IT174927, and IT906998, scored 0% disease incidence under high inoculum density of P. capsici ($10^6$ zoosporangia/mL). We recommend that these candidate melon germplasm may be used as genetic resources in the breeding of melon varieties resistant to Phytophthora rot.

• KSBB Journal
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• 제14권6호
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• pp.665-671
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• 1999

본 연구에서는 식물 유래의 항암제인 taxol을 생산하는 주목세포의 현탁배양을 통하여 taxol 반합성의 전구체인 10-deacetylbaccatin III(10-DAB)의 생산을 증대시키고자 하였다. 이 차대사산물의 생산이 세포생장과 관련이 있으므로 세포생장이 우수한 배지를 선택하기 위한 실험을 수행하였고, SH 배지에서 가장 우수한 세포생장이 관찰되었다. 또한 선택된 SH 배지에서 우수한 세포생장과 10-DAB 생산을 얻기 위해 초기 접종농도와 당농도의 변화를 관찰하였다. 초기 접종농도와 당농도가 낮을수록 세포생장이 빠르며, 낮은 초기 당농도와 초기 접종농도 6 g/L FCW 이었을 때 10-DAB의 생산이 우수하였다. 생산성을 높이기 위한 고농도 세포생장과 배지로의 10-DAB 분비를 목적으로 perfusion culture를 도입하였다. 고농도 당을 첨가한 배지로 perfusion을 수행한 결과 배양 후반까지 세포생장이 가능하였고, FCW/DCW ratio가 감소되어 대조구의 2.5배인 34.67 g/L의 높은 세포농도를 얻을 수 있었다. 10-DAB의 생산은 perfusion 시작후 10일 동안은 배지로 배출된 양이 세포내보다 높았다.

• The Plant Pathology Journal
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• 제16권6호
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• pp.312-317
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• 2000

The selected five plant growth-promoting rhizobacteria (PGPR) strains, WR8-3 (Pseudomonas fluorescens), WR8-6 (P. putida), WR9-9 (P. fluorescens), WR9-11 (Pseudomonas sp.), and WR9-16 (P. putida) isolated in the rhizosphere of watermelon plants were tested on their growth promotion and control effect against gummy stem rot of watermelon. Strains, WR8-3 and WR9-16 significantly increased stem length of watermelon, and there was a little increase in leaf area, fresh weight and root length when strains, WR8-3, WR9-9 and WR9-16 were treated. Generally, seed treatment was better for plant growth promotion than the soil drench, but there was no significant difference. Seed treatment and soil drench of each bacterial strain also significantly reduced the mean lesion area (MLA) by gummy stem rot, but there was no significant difference between the two treatments. At initial inoculum densities of each strain ranging from 10$^6\;to\;10^{15}$ cfu/g seed, approximately the same level of disease resistance was induced. But resistance induction was not induced at the initial inoculum density of 10$^3$ cfu/g seed. Resistance was induced by treating the strains, WR9-9, WR9-11 and WR9-16, on all of four watermelon varieties tested, and there was no significant difference in the decrease of gummy stem rot among varieties. Populations of the strains treated initially at log 9-10 cfu/g seed, followed with a rapid decrease from planting day to 1 week after planting, but the population density was maintained above log 5.0 cfu/g soil until 4 weeks after planting. Generally no or very weak in vitro antagonism was observed at the strains treated excepting WR9-11. Rifampicin-resistant bacteria which had been inoculated were not detected in the stems or leaves, which suggesting that the bacterium and the pathogens remained spatially separated during the experiment. This is the first report of rsistance induction in watermelon to gummy stem rot by PGPR strains.

• Korean Chemical Engineering Research
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• 제61권2호
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• pp.278-286
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• 2023

The present work evaluated the production of biohydrogen under mesophilic and thermophilic conditions through dark fermentation of palm oil mill effluent (POME) in batch mode using the design of experiment methodology. Response surface methodology (RSM) was applied to investigate the influence of the two significant parameters, POME concentration as substrate (5, 12.5, and 20 g/l), and volumetric substrate to inoculum ratio (1:1, 1:1.5, and 1:2, v/v.%), with inoculum concentration of 14.3 g VSS/l. All the experiments were analyzed at 37 ℃ and 55 ℃ at an incubation time of 24 h. The highest chemical oxygen demand (COD) removal, hydrogen content (H₂%), and hydrogen yield (HY) at a substrate concentration of 12.5 g COD/l and S:I ratio of 1:1.5 in mesophilic and thermophilic conditions were obtained (27.3, 24.2%), (57.92, 66.24%), and (6.43, 12.27 ml H₂/g COD_rem), respectively. The results show that thermophilic temperature in terms of COD removal was more effective for higher COD concentrations than for lower concentrations. Optimum parameters projected by RSM with S:I ratio of 1:1.6 and POME concentration of 14.3 g COD/l showed higher results in both temperatures. It is recognized how RSM and optimization processes can predict and affect the process performance under different operational conditions.