• 한국산학기술학회논문지
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• 제4권4호
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• pp.387-390
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• 2003

동ㆍ식물성 기름으로부터 산이나 알카리 촉매를 사용하여 제조한 친환경 에너지인 바이오디젤의 미생물학적 안정성을 테스트하기 위하여 온도와 저장기간에 따른 미생물에 의한 변질정도를 측정하였다. 측정방법으로 역상 현미경 관찰과, 3M petrifilm분석법으로 생균수를 측정하였고, 균체 단백질의 양을 측정하기 위하여 Bradford protein assay법을 사용하였다. 바이오디젤과 석유디젤, 그리고 각각의 시료를 혼합한 시료를 서로 다른 온도조건(25℃와 35℃)에서 혐기적인 조건으로 90일동안 장기간 저장했을 때 바이오디젤, 석유디젤 그리고 혼합한 시료에서 미생물의 생육은 관찰되지 않았다.

• 한국물환경학회지
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• 제31권3호
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• pp.328-333
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• 2015

In this study, Mg-Sericite was used as a flocculant to harvest freshwater microalgae, Chlorella. vulgaris. Mg-Sericite separated successfully >95% of the C. vulgaris at the following optimal parameters: Mg/Si mol ratio 1.25 to 1.50, mixing time of 20 min and settling time of 20 min. The harvesting efficiency was pH dependent. The highest harvesting efficiency ($99{\pm}0.3%$) was obtained at Mg/Si mol ratio 1.5 and pH 9 to 11. These results indicated that a biopolymer, Mg-Sericite, can be a promising flocculant due to its high efficiency, low dose requirements, short mixing and settling times. This harvesting method is helpful to lower the production cost of algae for biodiesel.

• 한국자동차공학회논문집
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• 제10권2호
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• pp.15-22
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• 2002

Lately, our world is faced with very serious problems related to the increased air pollution of the exhaust emissions from automobiles. In particular, the exhaust emissions of diesel engines are recognized as a main cause which strongly influence environment. Lots of researchers have attempted to develop various alternative fuels to reduce these harmful emissions in diesel engine. The purpose of this investigation is to evaluate the possibility of esterfied rice bran oil for diesel fuel substitution in a naturally aspirated D. 1. diesel engine, and also find means to reduce smoke emissions in esterfied rice bran oil combustion. The smoke emission of esterfied rice bran oil is reduced remarkably in comparison with commercial gas oil, that is, it was reduced approximately 58.2% at 2500rpm. But, power, torque and brake specific energy consumption didn't have no large differences. It was concluded that esterfied rice bran oil can utilize effectively as an alternative and renew- able fuel fur diesel engine.

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2008년도 춘계학술발표회
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• pp.304-305
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• 2008

• 한국육종학회지
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• 제42권2호
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• pp.121-128
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• 2010

Finding alternative and renewable energy sources has become an important goal for plant scientists, especially with the demand for energy increasing worldwide and the supply of fossil fuel being depleted. The most important biofuel to date is bioethanol which is produced from sugars (sucrose and starch) found in corn and sugarcane. Second generation bioethanol is targeting studies that would allow the use of the cell wall (lignocellulose) as a source of carbon by non-food plants. Plant scientists, including breeders, agronomists, physiologists and molecular biologists, are working towards the development of new and improved energy crops especially, how to design crops for bioenergy production and increased biomass generation for biofuel purposes. This review focuses on: i) the current status of first generation bioenergy production, ii) the limitations of first and second generation bioenergy, and iii) ongoing research to overcome challenging issues in second generation bioenergy.

• Environmental Engineering Research
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• 제24권2호
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• pp.271-278
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• 2019

Mass cultivation of microalgae is necessary to achieve economically feasible production of microalgal biodiesel. However, the high cost of nutrients is a major limitation. In this study, corncob extract (CCE) was used as an inorganic and organic nutrient source for the mass cultivation of Chlorella vulgaris (C. vulgaris). Chemical composition analysis of CCE revealed that it contained sufficient nutrients for mixotrophic cultivation of C. vulgaris. The highest specific grow rate of C. vulgaris was obtained at pH of 7-8, temperature of $25-30^{\circ}C$, and CCE amount of 5 g/L. In the analysis using various growth models, Luong model was found to be the most suitable empirical formula for mass cultivation of C. vulgaris using CCE. Analysis of biomass and production of triacyglycerol showed that microalgae grown in CCE medium produced more than 17.23% and 3% more unsaturated fatty acids than cells cultured in Jaworski's Medium. These results suggest that growing microalgae in CCE-supplemented medium can increase lipid production. Therefore, CCE, agricultural byproduct, has potential use for mass cultivation of microalgae.

• Journal of Microbiology and Biotechnology
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• 제32권2호
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• pp.170-175
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• 2022

3-Hydroxypropionic acid (3HP) is a platform chemical and can be converted into other valuable C3-based chemicals. Because a large amount of glycerol is produced as a by-product in the biodiesel industry, glycerol is an attractive carbon source in the biological production of 3HP. Although eight 3HP-producing aldehyde dehydrogenases (ALDHs) have been reported so far, the low conversion rate from 3-hydroxypropionaldehyde (3HPA) to 3HP using these enzymes is still a bottleneck for the production of 3HP. In this study, we elucidated the substrate binding modes of the eight 3HP-producing ALDHs through bioinformatic and structural analysis of these enzymes and selected protein engineering targets for developing enzymes with enhanced enzymatic activity against 3HPA. Among ten AbKGSADH variants we tested, three variants with replacement at the Arg281 site of AbKGSADH showed enhanced enzymatic activities. In particular, the AbKGSADH^R281Y variant exhibited improved catalytic efficiency by 2.5-fold compared with the wild type.

• Advances in Energy Research
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• 제8권3호
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• pp.175-184
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• 2022

The dual-fuel technology, which uses gaseous fuel as the main fuel and liquid as the pilot fuel, is an appealing technology for reducing the exhaust emissions. The current study proposes emission models based on ANFIS for a dual-fuel using producer gas (PG)-diesel engine. Emissions measurements were taken at different engine load levels and fuel injection timings. The proposed model predictions were examined using statistical methods. With R2 values in the range of 0.9903 to 0.9951, the established ANFIS model was found to be consistently robust in predicting emission characteristics. The mean absolute percentage deviate in range 1.9 to 4.6%, and mean squared error varies in range 0.0018 to 13.9%. The evaluation of the ANFIS model developed shows a reliable claim of intrinsic sensitivity, strength, and outstanding generalization. The presented meta-model can be used to simulate the engine's operation in order to create an efficient control tool.

• 한국버섯학회지
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• 제13권1호
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• pp.56-62
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• 2015

양송이 수확후 배지로부터 lipase 생산균을 분리하여 16S rDNA 유전자 분석을 통해 동정한 결과, Burkholderia cepacia ATCC와 99.8% 상동성을 나타냈다. 분리균 B. cepacia 배양여액 중에 함유된 효소단백질을 70% 황산암모늄으로 침전시켜 crude lipase를 회수하였다. 고정화 효소를 제조하기 위하여 crude lipase(CL)과 Novozyme lipase(NL)을 cross-linking 법에 의해 Silane화된 Silicagel에 고정화 시킨 결과, immobilized CL(ICL)은 61%, immobilized NL(INL)은 72%의 잔존활성을 유지하였다. 중성지방 Canola oil을 알칼리(NaOH) 촉매와 효소(CL 및 ICL) 촉매를 이용하여 지방산(fatty acid)으로 분해한 후, methanolysis에 의한 에스터전이반응(trans-esterification)을 통해 지방산으로부터 전환된 바이오디젤(fatty acid methyl ester, FAME)의 종류와 수율을 비교 하였다. 생성된 총 FAME 함량은 NaOH $781mg\;L^{-1}$, free lipase $681mg\;L^{-1}$, 고정화 lipase $598mg\;L^{-1}$순으로 높았으며, 지방산 조성별 FAME 함량은 linoleic acid(C18:1)가 약 50%로 가장 높았으며, stearic acid(C18:0)가 22%정도의 높은 수준이었다. 또한 반응시간이 증가함에 따라 CL과 ICL 모두 불포화지방산 FAME의 조성비는 감소하고, 상대적으로 포화지방산 FAME의 조성비는 증가하는 경향을 보여 lipase 효소가 transesterification 활성과 interesterification 활성을 동시에 가지는 것으로 여겨진다. 고정화효소의 잔여활성은 반복회수가 증가함에 따라 서서히 감소하여 4회 반복 후, 초기 활성도에 비해 ICL은 34% 와 INL은 21%까지 감소하였다.

• 생명과학회지
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• 제27권10호
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• pp.1137-1144
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• 2017

미세조류 Chlorella vulgaris는 바이오 디젤 생산을 위한 중요한 대체원료 중 하나로 간주되어 왔으나, 이러한 미생물의 산업적 적용은 낮은 바이오 매스와 지질 생산성에 의해 제약을 받아왔다. 따라서 이러한 문제를 극복하기 위해 본 연구는 자외선을 이용한 무작위 돌연변이 유발 기술을 통해 높은 지질 및 바이오 매스 생산성을 가지는 C. vulgaris 균주를 분리하고 그 특성을 규명하였으며, 두 가지 유형의 대량 생산 시스템을 이용하여 바이오 매스 및 지질 함량의 산출량을 비교하였다. 분리된 돌연변이 균주 중, 특히 실험실 조건에서 UBM1-10으로 명명된 돌연변이 균주는 야생형 균주에 비해 약 1.5배 높은 세포 수율 및 지질 함량을 보였다. 이러한 결과를 바탕으로 UBM1-10을 선택하여 TBPR (tubular photobioreactor)과 OPR (open pond type reactor)의 두 가지 유형의 반응기를 사용하여 실외 배양 조건에서 배양하였다. 그 결과 TBPR에서 재배된 돌연변이 균주의 세포 수율은($2.6g\;l^{-1}$) OPR에서 배양된 균주의 세포 수율($0.5g\;l^{-1}$)과 비교하였을 때 약 5배 이상의 높은 세포 수율을 나타내었으며, 대량 배양 후, UBM1-10 및 모 균주의 조 지방 함량 및 조성 등에 대해 추가로 조사를 실시하였다. 그 결과 C. vulagris UBM1-10균주의 지질함량(0.3% w/w)이 모 균주의 지질함량(0.1%)에 비해 약 3배 이상의 조 지방 함량을 보유함을 확인하였다. 따라서 이 연구는 바이오 디젤 생산 자원으로서 C. vulgaris의 경제적 잠재성이 photoreactor type의 선택 및 전략적 돌연변이 분리 기술을 통해 증가 될 수 있음을 보여 주었다.