• 한국미생물·생명공학회지
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• 제23권5호
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• pp.624-631
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• 1995

The fermentation characteristics of Saccharomyces cerevisiae F38-1, a newly isolated thermotolerant yeast strain from a high temperature environment have been studied using a fermentation medium containing 20% glucose, 0.2% yeast extract, 0.2% polypeptone, 0.3% (NH$_{4}$)$_{2}$SO$_{4}$, 0.1% KH$_{2}$PO$_{4}$, and 0.2% MgSO$_{4}$ without shaking at 30$\circ$C to 43$\circ$C for 5 days. The fermentability was over 90% at 30$\circ$C, 88% at 37$\circ$C, 77% at 40$\circ$C and 30% at 43$\circ$C. A similar fermentation result was obtained at pH between 4 and 6 at 30$\circ$C and 40$\circ$C. Aeration stimulated the growth of the strain at the beginning of the fermentation, but it reduced alcohol production at the end of alcohol fermentation. Optimal glucose concentration was determined to be between 18 and 22% at 40$\circ$C as well as 30$\circ$C, but the growth was inhibited at the glucose concentration of over 30%. A fermentability of over 90% was observed at 40$\circ$C in 2 days when the medium was supplemented by 2% yeast extract. A higher inoculum size increased the initial fermentation rate, but not the fermentation. A fermentability of over 90% was achieved in 2 days at 40$\circ$C in a fermentor experiment using an optimized medium containing 20% glucose and 1% yeast extract.

• Journal of Microbiology and Biotechnology
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• 제23권10호
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• pp.1460-1471
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• 2013

Microalgal biofuel production from wastewater has economic and environmental advantages. This article investigates the lipid production from high chemical oxygen demand (COD) bioethanol wastewater without dilution or additional nutrients, using a newly isolated heterotrophic microalga, Chlorella vulgaris LAM-Q. To enhance lipid accumulation, the combined effects of important operational parameters were studied via response surface methodology. The optimal conditions were found to be temperature of $22.8^{\circ}C$, initial pH of 6.7, and inoculum density of $1.2{\times}10^8cells/ml$. Under these conditions, the lipid productivity reached 195.96 mg/l/d, which was markedly higher than previously reported values in similar systems. According to the fatty acid composition, the obtained lipids were suitable feedstock for biodiesel production. Meanwhile, 61.40% of COD, 51.24% of total nitrogen, and 58.76% of total phosphorus were removed from the bioethanol wastewater during microalgal growth. In addition, 19.17% of the energy contained in the wastewater was transferred to the microalgal biomass in the fermentation process. These findings suggest that C. vulgaris LAM-Q can efficiently produce lipids from high-concentration bioethanol wastewater, and simultaneously performs wastewater treatment.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권3호
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• pp.194-199
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• 2001

Chlorella kessleri cultivated in artificial wastewater using diurnal illumination of 12h light/12h dark (L/D) cycles. The inoculum density was 10(sup)5 cells/mL and the irradiance in light cycle was 45$\mu$mol㎡s(sup)-1 at the culture surface. As a control culture, another set of flasks was cultivated under continuous illumination. Regardless of the illumination scheme, the total organic carbon (TOC) and chemical oxygen demand (COD) was reduced below 20% of the initial concentration within a day. However, cell concentration under the L/D lighting scheme was lower tan that under the continuous illuminating scheme. Thus the specific removal rate of organic carbon under L/D cycles was higher than that under continuous illumination. This result suggested that C. kessleri grew chemoorganotrophically in the dark periods. After 3 days, nitrate was reduced to 136.5 and 154.1mg NO$_3$-N/L from 168.1mg NO$_3$-N/L under continuous illumination and under diurnal cycles, respectively. These results indicate nitrate removal efficiency under continuous light was better than that under diurnal cycles. High-density algal cultures using optimized photobioreactors with diurnal cycles will save energy and improve organic carbon sources removal.

• Journal of Microbiology and Biotechnology
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• 제25권1호
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• pp.26-32
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• 2015

Four types of straw, namely, soybean, wheat, corn, and rice, were investigated for use in lactic acid production. These straws were mainly composed of cellulose, hemicellulose, and lignin. After pretreatment with ammonia, the cellulose content increased, whereas the hemicellulose and lignin contents decreased. Analytical results also showed that the liquid enzymatic hydrolysates were primarily composed of glucose, xylose, and cellobiose. Preliminary experiments showed that a higher lactic acid concentration could be obtained from the wheat and soybean straw. However, soybean straw was chosen as the substrate for lactic acid production owing to its high protein content. The maximum lactic acid yield (0.8 g/g) and lactic acid productivity (0.61 g/(l/h)) were obtained with an initial reducing sugar concentration of 35 g/l at 30℃ when using Lactobacillus casei (10% inoculum) for a 42 h fermentation period. Thus, the experimental results demonstrated the feasibility of using a soybean straw enzymatic hydrolysate as a substrate for lactic acid production.

• Environmental Engineering Research
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• 제25권4호
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• pp.561-570
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• 2020

In the present study, dye decolorizing bacteria were isolated from water and soil samples, collected from textile industries in Jodhpur province, India. Two bacterial species namely, Bacillus pumilis and Paenibacillus thiaminolyticus were screened and identified based on biochemical characterization. The degradation efficiency of these two microorganisms was compared through optimization of pH, incubation time, initial dye concentration and inoculum size. B. pumilis and P. thiominolyticus were able to degrade 61% and 67% Red HE3B, 81% and 75% Orange F2R, 49.7% and 44.2% Yellow ME4GL and 61.6% and 59.5% Blue RC CT dyes of 800mg/l concentration respectively. The optimum pH and time were found to be 8 within 24 hours. The FT-IR analysis confirmed that microorganisms were able to degrade toxic azo dyes into a non-toxic product as proved through structural modifications to analyze chemical functions in materials by detecting the vibrations that characterize chemical bonds. It is based on the absorption of infrared radiation by the microbial product. Therefore, Bacillus pumilis and Paenibacillus thiaminolyticus are a promising tool for decolorization of dyes due to its potential to effectively decolorize higher azo dye concentrations (10-800 mg/L) and can be exploited for bioremediation.

• The Plant Pathology Journal
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• 제32권6호
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• pp.508-518
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• 2016

Early blight of tomato caused by Alternaria solani, is responsible for severe yield losses in tomato. The conidia survive on soil surface and old dry lower leaves of the plant and spread when suitable climatic conditions are available. Macroclimatic study reveals that highest inoculum concentration of Alternaria spores appeared in May 2012 to 2013 and lowest concentration during January 2012 to 2013. High night temperature positively correlated and significantly (P < 0.01) involved in conidial spore dispersal and low relative humidity (RH) displayed significant (P < 0.05) but negative correlation with conidial dispersal. The objective of the study was to modify microclimatic conditions of tomato crop canopy which may hamper conidial dispersal and reduce disease severity. We evaluated effect of marigold intercropping and plastic mulching singly and in consortia on A. solani conidial density, tomato leaf damage and microclimatic parameters as compar to tomato alone (T). Tomato-marigold intercropping-plastic mulching treatment (T + M + P) showed 35-39% reduction in disease intensity as compared to tomato alone. When intercropped with tomato, marigold served as barrier to conidial movement and plastic mulching prevented evapotranspiration and reduced the canopy RH that resulted in less germination of A. solani spores. Marigold intercropping and plastic mulching served successfully as physical barrier against conidial dissemination to diminish significantly the tomato foliar damage produced by A. solani.

• 한국응용곤충학회지
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• 제27권3호
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• pp.159-164
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• 1988

Five nematophagous fungi were evaluated for their nematicidal effect in vitro on Rhabditis sp. and Meloidogyne hapla in soil. Inocula of Arthrobotrys arthrobotryoides, A. conoides, A. oligospora, Dactylella lobata, and Fusarium oxyaporum were grown in moistened corn-sandy soil and chopped potato-sandy soil media, and incubated at 26$^{\circ}C$ for one week. The prepared inocula were incorporated in autoclaved sandy soil, mixing thoroughly at rates equ-invalent to 1:50, 1:100, 1:200, and 1:400, repectively, before 80g of the mixture carrying 100 Rhabditis sp. was put into petri plates. Nematophagous fungi effectively teduced the popuation of Rhabditis sp. in soil in a week or two following treatment of the incula at concentration of 1:50 and 1:100. The optimum was at $25^{\circ}C$ for nematicidial effect as high as 80-100%. The at the rate of 1:100 prepared incula were incorporated in auto-claved soil, where 100 Juveniles M. hapla were introduced per 80% soil. All fungi infected the M. hapla effectively in soil, caysing more than 90% mortality within one week. This result indicated the potential value of these fungi as promising biocontrol agents.

• 유기물자원화
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• 제9권1호
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• pp.65-72
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• 2001

음식물쓰레기 퇴비화를 위한 발효흙 제조를 위하여 토양에서 새로 분리한 Bacillus속의 GM103, V25, V31, V35의 4균주를 사용하였다. 각 균주를 동정한 결과 각각 Bacillus licheniformis, B. subtilis, B. stearothermophilius, B, subtilis로 동정되었다. 이들 균주들은 단백질 분해능, 전분분해능, 그리고 작물 병원성 곰팡이 Rhizopus stronifer에 대한 저해능이 모두 우수하였다. GM103은 전분분해능이 탁월하게 우수하였고, 호기적 성장만 가능하였다. V25, V3l, V35는 모두 호기적 혐기적 성장이 가능하였고, 10% 염분농도와 $50^{\circ}C$에서 좋은 성장도를 보였으며, 토양에서의 생존 및 적응력도 우수하였다. 음식물쓰레기 퇴비화 시험을 위하여 GM103, V25, V31, V35 균주를 배양하여 당밀, 비트펄프, zeolite 등을 혼합하여 발효흙인 BIOTOP-CLEAN을 제조하였다. 제조된 BIOTOP-CLEAN과 무처리구인 대조구, 기존 타사 제품 HS와 음식물쓰레기 시험을 하였는데 대조구의 $30^{\circ}C$, HS의 $35^{\circ}C$ 보다 BIOTOP-CLEAN의 경우가 최대 발효온도는 $50^{\circ}C$로 가장 높았다. 또한 BIOTOP-CLEAN은 냄새도 구수하였고 성상에 있어서도 짙은 암갈색으로 음식물쓰레기의 퇴비화가 가장 잘 되었다. 한편 대조구는 악취가 나고 HS는 별다른 냄새가 없었다. 각 균주의 배양액을 토마토, 배추, 열무, 고추 등의 작물에 1달주기로 살포하여 무처리인 대조구에 비해 상대적 증산율에서 모두 우수한 것으로 나타났다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.315-316
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• 2001

In this study various nutritional and environmental parameters such as, initial moisture content, pH. inoculum size, air rate, sample size and nutrient supplement that influence pigment production were evaluated in solid-state cultures. optimum initial moisture content and pH were determined to be 50% and 6.0, respectively. The supplement of the substrate with different carbon, nitrogen, and mineral source reveals a more inhibitive effect as the substrate concentration increase. optimum aeration rate was determined to be 2vvm in flask culture. The maximum amount of red pigment, 3500 OD/g dried fermented rice, was obtained in optimum conditions which is obtained in solid flask culture.

• Journal of Microbiology and Biotechnology
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• 제8권2호
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• pp.185-187
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• 1998

Pseudomonas putida KCTC 2401 degrades 1,1, 2-trichloroethylene (TCE) using phenol as a cosubstrate. The initial TCE degradation rate decreased with the initial TCE concentration up to 20mg/l of TCE at $30^{\circ}C$ and pH 6.5. The initial degradation rate and total removal efficiency increased with inoculum size. The strain also degraded dichloroacetic acid, which was supposed to be a degradation by-product. Phenol monooxygenase apparently participates in the TCE degradation mechanism.