• Microbiology and Biotechnology Letters
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• v.46 no.4
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• pp.377-389
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• 2018

In this study, a novel microalgal strain, Desmodesmus sp. KAERI-NJ5, was isolated, identified, and evaluated as a candidate for biodiesel feedstock. In a preliminary study, the effects of four general microalgal growth factors, including temperature, pH, light intensity, and concentration of nitrogen source ($KNO_3$), on the microalgal photoautotrophic growth were evaluated. With the exception of light intensity, the growth factors needed to be optimized for the microalgal biomass production. Optimization was done using response surface methodology. The optimal conditions for biomass production were pH 6.54, $27.66^{\circ}C$, and 0.52 g/l $KNO_3$. The biomass production at the optimal conditions was 1.55 g/l, which correlated well with the predicted value of 1.5 g/l. The total lipid and fatty acid methyl ester contents of the cells grown at the optimal conditions were 49% and 21.2% of cell dry weight, respectively. To increase the lipid content of the biomass, microalgae were challenged by nitrogen starvation. Enhancement of total lipid and fatty acid content up to 52.02% and 49%, respectively, were observed. Lipid analysis of the nitrogen-starved cells revealed that C16 and C18 species accounted for 95.9% of the total fatty acids. Among them, palmitic acid (46.17%) and oleic acid (39.43%) dominantly constituted the algal fatty acids. These results suggest Desmodesmus sp. KAERI-NJ5 as a promising feedstock for biodiesel production.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.579-584
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• 2007

대두유로부터 생산된 바이오디젤과 바이오디젤 혼합 연료유를 대상으로 지방산메틸에스터 함량과 화학적 분석을 통해 산화 특성과 오일의 수명 예측 연구를 수행하였다. 바이오디젤, 경유, BD5, BD20은 산화가 진행될수록 산가(Acid number), 동점도(Kinematic Viscosity) 및 밀도(Density)는 증가하였다. 산가 측정결과의 활용에 의해 임의의 온도조건에서 정확한 사용수명을 예측하기 위하여 화학속도론에 의거하여 각각의 연료에 대한 사용수명식을 도출하였다. 도출된 사용수명식으로부터 바이오디젤이 가장 빠르게 산화가 진행되었고 바이오디젤 혼합량이 증가할수록 사용수명이 단축되는 것을 확인할 수 있었다.

• New & Renewable Energy
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• v.3 no.2 s.10
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• pp.17-23
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• 2007

대두유로부터 생산된 바이오디젤과 바이오디젤 혼합 연료유를 대상으로 지방산메틸에스터 함량과 화학적 분석을 통해 산화 특성과 오일의 수명 예측 연구를 수행하였다. 바이오디젤, 경유, BD5, BD20은 산화가 진행될수록 산가(Acid number), 동점도(Kinematic Viscosity) 및 밀도(Density)는 증가하였다. 산가 측정결과의 활용에 의해 임의의 온도조건에서 정확한 사용수명을 예측하기 위하여 화학속도론에 의거하여 각각의 연료에 대한 사용수명식을 도출하였다. 도출된 사용수명식으로부터 바이오디젤이 가장 빠르게 산화가 진행되었고 바이오디젤 혼합량이 증가할수록 사용수명이 단축되는 것을 확인할 수 있었다.

• Korean Journal of Pharmacognosy
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• v.6 no.1
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• pp.15-21
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• 1975

The free fatty acids were prepared from the ethereal fraction of Panax ginseng. The prepared acids were methylated with diazomethzne. The methyl esters of saturated and unsaturated fatty acids were separated by the means of mercuric acetate method and column chromatography. The separated methyl esters were gaschromatographed and analyzed. The obtained conclusions were as follows. 1. The root of six-year old Korean Panax ginseng contains 0.28% of free fatty acids. 2. It was found that 24 kinds of free fatty acids existed in Panax ginseng. Among them, 22 kinds of free fatty acids were indentified by the gas chromatogram and the graphical method but the rest, 2 kinds of them were not identified by the only gas chromatographical data. The amount of each free fatty acid which was not identified was predominant and they were supposed to be unusual free fatty acids which would not commonly exist in nature. These results were shown in Table III. 3. $L_{EE}$ and $L_{EE}$ reported that n18:3 existed in Panax ginseng. However, in this experiment, n18:3 did not exist in Panax ginseng, and instead, peak XVI appeared between n18:2 and n18:3 as shown in Fig. 9.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.2
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• pp.149-154
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• 2007

An antibacterial substance to the Streptococcus mutans, a causative bacterium for decayed teeth, was isolated from the dried sea mustard, Undaria pinnatifida, and identified by GC and GC/MS. Acetone extract from the sea mustard (10.4 kg), was evaporated and partitioned to 4 fractions such as hexane, chloroform, butanol and water. The most active chloroform fraction were further purified through basic alumina, silicic acid and ODS column, successively, and finally, 3 antibacterial substances were isolated on the HPLC attached ODS column by using 95% MeOH and guided with UV detector (254 nm). Antibacterial substances (total 160mg, yield $1.5\times10^{-3}$%) had the same Rf value (0.42) on the TLC developed hexane diethyl ether acetic acid (80:30:1) and those methyl esters moved to 0.95. They were identified as the same unsaturated fatty acid, $C_{18:4,\;n-3}$ (3,6,9,12-octadecatetraenoic acid, stearidonic acid) compared relative retention times (15.5 min) with authentic fatty acid on the GC chromatogram. It was further confirmed unambiguously on the GC/MS giving molecular ion peak at m/z 290 which coincided with its methyl ester.

• Journal of the Korean Applied Science and Technology
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• v.31 no.1
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• pp.113-119
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• 2014

The compositions of saturated and unsaturated fatty acids in biodiesel feedstocks are important factors for biodiesel properties including low-temperature fluidity and oxidative stability. This study was conducted to improve low-temperature fluidity of biodiesel by reducing total saturated FAME (fatty acid methyl ester) in animal fat biodiesel fuels via urea-based fractionation and by mixing plant biodiesel fuels (rapeseed-FAME, waste cooking oil-FAME, soybean-FAME, and camellia-FAME) with enriched-polyunsaturated FAME derived from animal fat biodiesel. Our results showed that the reduction of total saturated FAME in animal fat biodiesel lowered CFPP (Cold Filter Plugging Point) to $-15^{\circ}C$. Mixing plant biodiesel fuels with the enriched-polyunsaturated FAME derived from animal fat biodiesel lowered CFPP of blended biodiesel fuels to $-10{\sim}-18^{\circ}C$.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.2
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• pp.221-227
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• 2011

Applications of green manures generally improve the soil quality in rice paddy in part through restructuring of soil microbial communities. To determine how different green manures affect soil microbial communities during the early stages of rice growth, fatty acid methyl ester (FAME) profiles were used to the effects of different management practices: 1) conventional farming (CF), 2) no-treatment (NT), 3) Chinese milk vetch (CMV), 4) green barley (GB), and 5) triticale in paddy field. With applications of green manures, soil organic matter was significantly higher than CF, while soil Na concentration was significantly lower compared with CF (p<0.05). Total soil microbial biomass of CMV was higher (p<0.05) than NF by approximately 31%. The highest ratio of monounsaturated fatty acid to saturated fatty acid was found in the GB plot, followed by CMV and triticale compared with CF (p<0.05), possibly indicating that microbial stress was less in GB and CMV plots. Populations of Gram-negative bacteria and arbuscular mycorrhizal fungi also were significantly higher green manures than CF (p<0.05). Our findings suggest that GB should be considered as optimum green manure for enhancing soil microbial community at an early growing stage in paddy field.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1005-1010
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• 2008

The genus Burkholderia consists of extremely versatile bacteria that occupy diverse niches and are commonly encountered in the rhizosphere of crop plants. In this study, we characterized three plant growth promoting strains assigned as Burkholderia sp. using biochemical and molecular characterization. The Burkholderia spp. strains CBMB40, CBPB-HIM, and CBPB-HOD were characterized using biochemical tests, BIOLOG carbon substrate utilization, fatty acid methyl ester analysis, analysis of recA gene sequences, and DNA-DNA hybridization. The results from these studies indicated that the strains CBMB40, CBPB-HIM, and CBPB-HOD can be assigned under Burkholderia vietnamiensis, Burkholderia ubonensis, and Burkholderia pyrrocinia, respectively.

• Tribology and Lubricants
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• v.29 no.2
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• pp.117-123
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• 2013

Dimethyl ether (DME) has a high cetane number that is suitable for diesel fuel. DME does not contain sulfur or nitrogen, and is an oxygenated fuel so it produces no particulate matter when combusted and is environmentally friendly. DME fuel for diesel engines show excellent material properties such as a lower volumetric heating value, lower boiling point, lower lubricity, and stronger solvent effect than light oil. This study experimentally examined a lubricity improver (LI) for dimethyl ether. A diesel LI based on biodiesel and fatty acid methyl ester was tested among DME LI candidates. The long-term storage stability and physical properties of the optimum LI for DME were determined.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.105.1-105.1
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• 2010

바이오디젤 보급 활성화에 따른 식물성 원료유의 가격 상승 및 수급 불안정성 문제를 해결하고자 폐유지를 원료로 바이오디젤을 생산하고자 하는 시도가 이루어지고 있다. 폐유지의 사용은 폐자원 활용 측면에서 의미가 있으며 바이오디젤 생산 단가를 낮출 수 있다. 다양한 폐유지가 산업체로부터 배출되며 이 중에서 dark oil은 식용유 공장에서 식물성 원료유의 정제 과정에서 생기는 부산물로 바이오디젤로 전환 가능한 성분을 포함하고 있다. 본 연구에 사용된 dark oil은 54.9%의 유리지방산과 28.0%의 triglyceride, 4.4%의 diglyceride, 그리고 1% 이하의 monoglyceride를 함유하고 있다. Dark oil의 초기 산가는 109.8 mg KOH/g이었다. 본 연구에서는 dark oil의 유지 부분(triglyceride, diglyceride, monoglyceride)을 유리지방산으로 전환시켜 HAAO(high acid acid oil)을 생산한 후, 고체 산 촉매에 의한 에스테르화 반응을 통하여 바이오디젤을 생산하고자 하였다. 유지 부분의 유리지방산 전환 반응을 위하여 음이온성 계면활성제인 SDBS(sodium dodecyl benzene sulfonate)가 사용되었다. Dark oil:황산:물의 질량비가 10:2:10이고 SDBS가 오일 대비 3%인 조건에서 dark oil의 산가는 190.8 mg KOH/g까지 증가하였고, dark oil:황산:물의 질량비가 10:4:10이고 SDBS가 2%인 조건에서는 산가가 194.2 mg KOH/g까지 증가하였다. 생산된 HAAO을 이용하여 오일 대비 30%의 Amberlyst-15 촉매 하에서 HAAO:메탄올 몰비 1:9인 조건에서 에스테르화 반응을 수행하였을 경우 FAME(fatty acid methyl ester) 함량은 81.3%까지 증가하였다. 고체 산 촉매로써 Amberlyst-15와 가격 면에서 저렴한 PC101을 비교하였을 경우 FAME 함량은 각각 80.7%, 77.9%로 비슷한 효율을 나타내었다. 생산된 바이오디젤의 FAME 함량을 높이기 위해 증류 공정을 필요로 하였다.