• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.513-513
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• 2009

최근 바이오디젤의 원료로 미세조류가 많은 관심을 끌고 있다. 미세조류는 물, 이산화탄소와 태양광을 이용해 광합성 성장이 가능하며, 지질(오일) 성분이 풍부하여 바이오디젤의 원료로 이용할 수 있다. 미세조류는 단위 면적당 오일 생산량이 곡물류의 50-100배 이상이며, 이산화탄소를 기질로 이용하므로 온실가스 직접 저감이 가능하다. 또한 배양시 비경작지나 황무지를 사용할 수 있으므로 기존 식용작물과 경쟁하지 않으며, 하수, 해수, 폐수 등 다양한 물자원을 이용할 수 있다. 본 연구에서는 고농도 $CO_2$에 내성을 지닌 Chlorella sp. KR-1을 대상으로 1 L 규모 기포탑 광생물반응기에서 균체 성장 및 지질(바이오오일) 합성에 대한 $CO_2$ 농도, 가스 공급속도, 질산염 농도 등 환경 및 영향 조건의 영향을 조사하였다. 가스 공급속도 0.4 L/min에서 $CO_2$ 농도를 0.03-20% 범위에서 조사하였을 때 최대 균체성장은 $CO_2$ 10%에서 관찰되었다. 균체내 지방산 함량은 $CO_2$ 농도 0.03%에서 가장 낮았고, 5-20% 범위에서는 $CO_2$ 농도 증가에 따라 감소하는 경향이 관찰되었다. 가스 공급속도를 0.2 L/min에서 0.8 L/min으로 증가시켰을 때 최대 균체농도는 0.6-0.8 L/min의 범위에서 관찰되었고, 생체내 최대 지방산 함량은 0.4 L/min에서 관찰되었다. Nitrate 농도 1-20 mM 범위에서 최종 균체농도는 nitrate 농도 증가에 따라 10mM까지 증가하였으나 그 이상에서는 증가하지 않았다. 반면 지방산 함량은 nitrate 농도 증가에 따라 감소하는 경향이 관찰되었다. 본 실험에서 얻은 최대 지방산 생산량은 1,100 mg/L이었으며, 주요 지방산은 C10:0(1.7%), C16:0(28.5%), C18:0(11%), C18:1n9c(25.9%), C18:2n6c(26.3%), C18:3n3(6.6%)이었다. 현재 100 L 규모 광생물반응기에서 석탄발전소 배가스($CO_2$ 12-15%, SOx 50ppm, NOx 100ppm)를 이용한 바이오오일 생산 실험이 진행 중이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5393-5399
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• 2014

To examine the effects of a mycosporine-like amino acids (MAAs) mixture from microalgae, Chlamydomonas sp, on the anti-wrinkle activities, the expression levels of genes that are associated with skin aging, including type I procollagen, elastin and involucrin, were analyzed. Asterina 330+palythine (A+P) and shinorine+palythine (S+P) mixtures were purified from Chlamydomonas sp using the following steps: 80% methanolic extraction, column purification, and HPLC analysis. As a result of the MTT assay, A+P and S+P did not induce cellular cytotoxicity with up to 0.1 mg/mL of both MAAs. In addition, the treatment of UV-exposed fibroblasts with A+P (0.05 mg/mL) and S+P (0.01 mg/mL) increased the levels of the PCOLCE mRNAs by 2.7 and 3.6 fold compared to the control group, respectively, The levels of elastin gene expression were elevated 5.59 and 3.1 fold in the A+P and S+P treated (0.01 mg/mL) cells, respectively. In particular, at a concentration of 0.01 mg /mL, the A+P and S+P expression levels of Involucrin mRNAs were increased 3.5 and 2.5 fold in the UV-exposed cells compared to the control, respectively. In conclusion, the MAAs derived from Chlamydomonas sp can be utilized as functional cosmetic materials with anti-wrinkle effects on the skin.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.33 no.4
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• pp.331-338
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• 2000

The algicidal effects of marine bacteria were investigated and a strain, which had the strongest algicidal activity against the harmful dinoflagellate, Cochiodinim polykrikoides was selected. The bacterium was isolated in seawater during the period of blooming of C. polykrikoides in Masan Bay. This algicidal bacterium was identified as Micrococcus sp. LG-5 by means of morphological and biochemical tests. The optimal culture conditions of Micrococcus sp, LG-5 were $25^{\circ}C,\;pH 7.0\;and\;3.0{\%}$ NaCl concentration. The algicidal activity of Micrococcus sp. LG-5 was significantly increased to maximum value in the late of logarithmic phase of cell cuture. In addition, the culture filtrate ($pore size,\;0.1{\mu}m$) of Microcoocus sp. LG-5 showed strong algicidal effects. The cell numbers of C. polykikoides were decreased from $1.2{\times}10^4 cells/ml\;to\;less\;than\;2{\times}10^3\;cells/ml$ within 3, 6, 30 hours at the concentrations of culture filtrate $10{\%},\;5{\%}\;and\;1{\%}$, respectively. These results indicated that the algicidal effect was mediated by certain substances released from Microooccus sp. LG-5.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.7
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• pp.467-472
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• 2012

The aim of this study was to investigate the efficiency of optical panel (OP) on the growth rate of Chlorella vulgaris (C. vulgaris). The size of C. vulgaris (FC-16) was 3~$8{\mu}m$, having round in shape. The cells of C. vulgaris was cultured in the Jaworski's Medium with deionized water at $22^{\circ}C$ for 15 days. For this experiment, three light samples were prepared to evaluate the efficiency of OP on the growth rate of C. vulgaris; OP with LED (Light Emitting Diode) (Run 1), Fluorescent light (Run 2) and LED (Run 3). The specific growth rate of C. vulgaris for Run 1 was found to be 14 times and 5 times faster than Run 2 and Run 3, respectively. In addition, the average biomass of C. vulgaris for Run 1 was measured 11.79 g/L in 11 days. This means that the biomass for Run 1 was reached 30 times and 6.5 times higher than Run 2 and Run 3, respectively. This may be due to the fact the OP was increased the light uniformity and hindered the shading effects in photobioreactor. Therefore, the growth rate of biomass in photobioreactor with OP is compared better than the without OP used other photobioreactor.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.2
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• pp.155-161
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• 2002

Tetraselmis suecica (T. suecica) of Prasinophyta was selected because the growth rate is comparatively higher and the culturing is also easy. In order to investigate antioxidative activity, the soluble elements of T. suecica were fractionated using water and organic solvents such as methanol, hexane, chloroform, ethylacetate and butanol. The chloroform fraction of T. suecica showed strong antioxidative activity. The potential antioxidative activity was detected in hexane: ethylacetate (1:5) once used the fractions by different mixtures of organic solvents. This fraction was further purified by preparative thin layer chromatography (PTLC) and repeated reverse-phase HPLC. On the basis of chemical and spectroscopic evidences obtained by UV, FT-IR, FAB-MS and NMR, the compound purified from T. suecica was identified as pheophorbide-a. The antioxidative activity of the compound was comparable to that of $\alpha$-tocopherol and could be act as an antioxidant in foods.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.1
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• pp.57-62
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• 1985

The three tide pools of Kanagawagen Aburatsubo coast, Japan were studied for 5 months (June-October, 1991) to know the physicochemical factors and changes of the microflora, In the tide pools salinity was ${\simeq}35\%0$, temperature range was $14{\sim}32^{\circ}C$ and pH range was $7.4{\sim}8.9$. Particulate organic carbon (POC) was $255{\sim}3980\;{\mu}g-at/l$, and total phosphate-P was $1.0{\sim}27.0\;{\mu}g-at/l$. The numbers of suspended bacteria and heterotrophic bacteria on the algae were $10^4{\sim}10^7/ml$ and $10^6{\sim}10^8/g$, respectively. Bacterial flora isolated from the Samples were Acinetobacter spp., Moraxella spp., Flavobacterium spp. and Pseudomonas spp., While Acinetobacter spp. was predominant among them. T. japonicus occurred dominantly with densities of $2200{\sim}7000/l$ during $August{\sim}september$. During this period the sharp increases of the unicellular microalgae and the protozoans were observed. According to the experimental results (POC, total phosphate-P, numbers and composition of bacterial flora), T. japonicus seemed to inhabit the environment with high eutrophication and high variability.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.1052-1058
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• 2005

Structured lipid (SL) was synthesized by enzymatic interesterification with algae oil containing docosahexaenoic acid (DHA) and soybean oil in the stirred-batch type reactor. The reaction was performed for 15hr at $65^{\circ}C$ with 300 rpm catalyzed by sn-1,3 specific Lipozyme RM 1M lipase from Rhizomucor miehei ($11\%$ by weight of total substrates) in the absent organic solvent. SL contained $87.1\;area\%$ triacylglycerol (TAG), $12.1\;area\%$ diacylglycerol (DAG), $0.6\;area\%$ monoacylglycerol (MAG), and $0.2\;area\%$ free fatty acid (FFA). Major fatty acid profiles of SL were DHA $(15.7\;mol\%)$, linoleic $(31.1\;mol\%)$, palmitic $(20.2\;mol\%)$, oleic $(13.5\;mol\%)$ and eicosapentaenoic acid $(EPA,\;6.6 mol\%)$. SL contained the newly synthesized several peaks. Iodine and saponification of SL were 206.7 and 183.8. SL color showed darker and redder than soybean oil, and appeared the most yellowish color among SL, soybean, and algae oil.

• KSBB Journal
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• v.25 no.6
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• pp.527-532
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• 2010

A thiazolidinedione derivative, TD49 with the highly selective algicide to red tide was newly synthesized and its acute toxicity was examined in order to evaluate the effect on aquatic ecosystems of coast. Major three species having important role in the food chain of marine ecosystem, such as Skeletonema costatum of microalgae, Daphnia magna of crustacea, Paralichthys olivaceus of flatfish fingerling were employed for the acute toxicity assessment. $EC_50$ or $LC_50$ as the assessment criterion was investigated to each specie, and NOEC (No Observed Effect Concentration) and PNEC (Predicted No Effect Concentration) from most sensitive specie to toxicity of TD49 were further calculated. $EC_50$ of S. costatum in 96-hour, $EC_50$ of D. magna in 48-hour, and $LC_50$ of P. olivaceus in 72-hour for TD49 were $0.34\;{\mu}M$, $0.68\;{\mu}M$, and $0.58\;{\mu}M$, respectively. NOEC from the results of S. costatum was estimated to be $0.20\;{\mu}M$ and PNEC was estimated as 3.40 nM by applying factor value of 100 to $EC_50$ $0.34\;{\mu}M$ of S. costatum. In addition, it was revealed that Solutol used as the dispersing agent of TD49 had very little toxic influence under the concentration range of $0{\sim}0.4\;{\mu}M$ used in TD49 toxicity experiment. Although the estimated concentration of TD49 that will be sprayed onto the coastal field for the algicide is higher than NOEC value, it is considered that the spraying concentration would not be a considerable problem due to a dilution effect by tide at the opened coast.

• Weed & Turfgrass Science
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• v.5 no.3
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• pp.136-143
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• 2016

This study was conducted to investigate the algicidal characteristics of cashew nut oil (CNO) and to develop CNO mixtures with other compounds having synergistic effects on the growth inhibition against a blue-green alga, Microcystis aeruginosa. Among tested CNOs, CNO with higher anacardic acid contents (Ana-A) exhibited the best algicidal activity against M. aeruginosa. Ana-A showed broad algicidal spectrum with particular greater activity against blue-green algae than green algae. Ana-A showed the greatest activity against to Oscillatoria tenuis ($IC_{50}=0.19{\mu}g\;mL^{-1}$) among the tested blue-green algae and to Chlorella vulgaris ($IC_{50}=4.54{\mu}g\;mL^{-1}$) among the tested green algae, respectively. In a mixture experiment to evaluate a chemical interaction in M. aeruginosa control, Ana-A showed a strong synergistic effect with MSB and menadione, mild synergistic effect with citric acid, and additive effect with chryspophanol, copper sulfate and quinoclamine. Taken together, our results suggest that CNO containing higher anacardic acid can be used as an eco-friendly natural algicide for selective control of blue-green algae such as M. aeruginosa and O. tenuis through an optimization of application rate and in combination with synergists such as MSB and menadione.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.279-287
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• 1993

Daily variation of particulate organic carbon(POC) and some factors controlling its level were examined for a semi-enclosed bay(Wonmun Bay, south coast of Korea), in which a lot of suspended oyster culture farms existed, in September, 1992. Observations were made at hourly interval. In spite of the relatively short survey period, strong short-term variation of POC concentration could be observed. Concentrations of POC were the range of $58{\sim}582{\mu}g/l(average 272{\mu}g/l)$ and their variation pattern was similar to those of chlorophyll a with the range of $0.90{\sim}7.25{\mu}g/l(average 3.35{\mu}g/l)$. The low C/N ratios also suggested that marine microalgae was a major component of POC for Wonmun Bay. Primary production, average $1.97\;gC/m^2/day$, was the main source of POC beacuse the supply of POC via freshwater input and exchange with the outer part of the bay was little. Oyster population also excreted a small amount of POC. About $40\%$ of produced POC was decomposed heterotrophically. Another important cause for the fluctuation of observed POC was tidal cycle. Considerable POC, which amounted $37\%$ of produced POC, was lost from the bay due to flushing by tidal cycle. It was also calculated that about $16\%$ was transported onto the sediment. It seemed that a part of POC was consumed by oyster and other heterotrophs.