산업 폐기물을 이용한 미세조류 유래 바이오 디젤 및 디에이치에이 생산 연구

학위논문(박사) - 한국과학기술원 : 생명화학공학과, 2016.2 ,[x, 105 p. :]The large amount of fossil fuels has been consumed since industrialization began in the 18th century. In addition, the expenditure of fossil fuels is being increasingly accelerated by an exploding population, nowadays. Although fossil fuels drove economic growth and supported the conveniences of life, they also gave rise to serious environmental problems since carbon dioxide $(CO^2)$. Therefore, in order to meet the present level of energy demands and alleviate climate change, it is inevitable that fossil fuels must be replaced by renewable, sustainable, and eco-friendly next-generation fuel. Moreover, it should be used as transportation fuel in liquid form. Microalgae can capture light energy from the sun and convert carbon dioxide to organic matter by photosynthesis. Due to its high oil productivity and rapid growth potential, microalgae are used as feedstock for third generation biofuel, which has potential to replace petroleum fuels in the foreseeable future. Some microalgae species can uptake organic carbon sources as energy and nutrients for their growth and lipid induction. This type of cultivation mode is called heterotrophic or mixotrophic cultivation. Although microalgae grow much faster with high lipid accumulation than phototrophic cells, organic carbon sources are required. Therefore, heterotrophic and mixotrophic cultivations can be costly and less economically feasible. In order to decrease the costs associated with microalgal cultivation including the carbon source and nutrients, we must find inexpensive carbon and nutrient sources for microalgae cultivation. In chapter 3, we measured the growth of and lipid production by the model microalga Chlamydomonas reinhardtii under different phototrophic, heterotrophic, and mixotrophic conditions to determine the optimal conditions for growth and biodiesel production. In particular, we examined cell growth and yield of fatty acid methyl esters (FAMEs) when C. reinhardtii was cultured in the presence of different organic carbon sources (acetate, glucose, glycerol, and sucrose). C. reinhardtii grew under various conditions, but mixotrophic cultivation was best. The greatest biomass production ($2.15 gL^{-1}$ in 5 days) and FAME yield (16.41% of biomass) were observed under mixotrophic cultivation with acetate $(10 gL^{-1})$. As an alternative to acetate, we additionally tested the use of volatile fatty acids (VFAsacetic, propionic, and butyric acids), which can be inexpensively produced through fermentation of food waste. The highest FAME yield (19.02% of biomass) and biomass production ($2.05 gL^{-1}$ in 5 days) were obtained with $5 gL^{1}$ of VFAs. This result indicates that VFAs can serve as an inexpensive alternative carbon source for maximizing lipid production in mixotrophic cultivation of C. reinhardtii. In chapter 4, the present study assessed the use of hydrolysate of lipid extracted algae (LEA) combined with the sugar factory wastewater (SFW) as a low cost nutrient and a carbon source, respectively for microalgal cultivation. Microalgal strain Ettlia sp. YC001 was both mixotrophically and heterotrophically cultivated using various amounts of hydrolysate and SFW. The culture which was grown in medium containing 50% LEA hydrolysate showed highest growth, achieving $5.26 ± 0.14 gL^{-1}$ after 12 days of cultivation. The addition of SFW increased the lipid productivity substantially from 5.8 to 95.5 $mgL^{-1}d^{-1}$ when the culture medium was fortified with 20% SFW. Gas chromatography analysis indicated a noticeable increase of 20% in C16 and C18 fraction in FAME distribution under above condition. Therefore, it can be concluded that the combination of LEA hydrolysate and sugar factory waste water can be a powerful growth medium for economical algal cultivation. In chapter 5, we considered the usage of sugar factory wastewater (SFW) as an inexpensive carbon source for cultivation of heterotroph marine strain Aurantiochytrium sp. KRS101 for the production of docosahexaenoic acid (DHA). The highest biomass yield (20.03 $gL^{-1}$ in 5 days) was obtained using 30% of SFW in medium, which was higher than that of pure glucose control (concentration of glucose: 30 $gL^{-1}$). In addition, the biomass was maximized to 22.44 ± 0.41 $gL^{-1}$ in 5 days by optimizing the concentration of N and P sources to 20 $gL^{-1}$ of yeast extract and 9 $gL^{-1}$ of monopotassium phosphate, respectively. Lipid accumulation and composition are affected by chemical and physical environmental stimuli such as salinity, temperature, and medium pH. In order to increase the DHA yield with a large amount of biomass, sea salt was added to medium on different cell growth phase. The highest DHA yield (2.03 $gL^{-1}$ in 5 days) was obtained when we increase initial sea salt concentration from 15 $gL^{-1}$ to 35 $gL^{-1}$ at stationary phase. In this study, we confirmed Aurantiochytrium sp. KRS101 can be successfully cultivated heterotrophically using an alternative carbon source from wastewaters. Moreover, DHA yield can be increased by environmental stimuli such as salinity. We believe that these findings may have a significant impact on the future technology development for DHA production using Aurantiochytrium sp. KRS101한국과학기술원 :생명화학공학과

Method for Extracting Lipid from Microalgae

본 발명의 미세조류에서 지질을 추출하는 방법에 관한 것으로, 더욱 자세하게는 미세조류 100 중량부에 대하여 6~262 중량부의 유기용매를 첨가한 혼합물을 하이쉬어믹서(High shear mixer)에 투여하여 미세조류에서 지질을 추출하는 방법에 관한 것이다. 본 발명은 적은 용매의 사용으로도 지질을 효과적으로 추출하고, 에너지 사용량을 상당히 감소시킬 수 있으며, 상기 추출과정에서 에멜젼이 생성되지 않아 지질 회수가 원활하며, 지질이 제거된 바이오매스와 유기용매가 중력에 의해 분리되어 유기용매의 회수도 용이하다

유기산으로 향상된 동전기 기술을 이용한 중금속 오염 토양 정화에 대한 연구

학위논문(석사) - 한국과학기술원 : 생명화학공학과, 2011.2, [ vi, 48 p. ]The contaminated soil near a Janghang facility in Chungnam in Korea was treated by electrokinetic (EK) remediation to remove heavy metals using organic aids. Electrokinetic remediation is a one of in situ techniques that can be applied to low hydraulic conductive soil. It is applicable for saturated soil with low groundwater flow rates. Generally, in order to increase the removal efficiency of contaminants with EK, chemical agents or strongly complexing agents are used. Organic acids have been known to increase the mobility of heavy metals in soil. Its advantages are eco-friendly and biodegradable. The acidic characteristic of organic acids is able to extract of heavy metals from soil due to cation exchange with heavy metals. For this reason, organic acids were used as an electrolyte in this study to achieve high removal efficiency of heavy metals. Before the EK experiment, extraction of heavy metals from the soil using various organic acids was conducted to investigate the feasibility of organic acids and find suitable organic acids to apply for EK system. Acetic acid, citric acid, formic acid, lactic acid and oxalic acid were used washing solution on soil washing test. In soil washing test, citric acid and oxalic acid showed high removal efficiency of heavy metals from soil. In the EK experiment using citric acid and oxalic acid, it showed higher removal heavy metals than conventional EK experiment using DW, but low current density and EOF was observed. In order to overcome these drawbacks, general electrolytes of EK such as $MgSO_4$, $NaNO_3$ was added to solution of organic acid. During that EK experiments, current density was increased by general electrolytes and also electroosmosis flow was higher than EK experiments using only organic acids. After the EK experiments, mobility of heavy was observed more clearly and removal efficiency of heavy metals was high than the EK using only organic acids. About 57 % of high heavy metals removal efficiency was ach...한국과학기술원 : 생명화학공학과

유기산으로 향상된 동전기 기술을 이용한 중금속 오염 토양 정화에 대한 연구

학위논문(석사) - 한국과학기술원 : 생명화학공학과, 2011.2, [ vi, 48 p. ]The contaminated soil near a Janghang facility in Chungnam in Korea was treated by electrokinetic (EK) remediation to remove heavy metals using organic aids. Electrokinetic remediation is a one of in situ techniques that can be applied to low hydraulic conductive soil. It is applicable for saturated soil with low groundwater flow rates. Generally, in order to increase the removal efficiency of contaminants with EK, chemical agents or strongly complexing agents are used. Organic acids have been known to increase the mobility of heavy metals in soil. Its advantages are eco-friendly and biodegradable. The acidic characteristic of organic acids is able to extract of heavy metals from soil due to cation exchange with heavy metals. For this reason, organic acids were used as an electrolyte in this study to achieve high removal efficiency of heavy metals. Before the EK experiment, extraction of heavy metals from the soil using various organic acids was conducted to investigate the feasibility of organic acids and find suitable organic acids to apply for EK system. Acetic acid, citric acid, formic acid, lactic acid and oxalic acid were used washing solution on soil washing test. In soil washing test, citric acid and oxalic acid showed high removal efficiency of heavy metals from soil. In the EK experiment using citric acid and oxalic acid, it showed higher removal heavy metals than conventional EK experiment using DW, but low current density and EOF was observed. In order to overcome these drawbacks, general electrolytes of EK such as $MgSO_4$, $NaNO_3$ was added to solution of organic acid. During that EK experiments, current density was increased by general electrolytes and also electroosmosis flow was higher than EK experiments using only organic acids. After the EK experiments, mobility of heavy was observed more clearly and removal efficiency of heavy metals was high than the EK using only organic acids. About 57 % of high heavy metals removal efficiency was ac...한국과학기술원 : 생명화학공학과

Method for Culturing Chlorella at High Concentration

본 발명은 고농도의 미세조류 배양방법에 관한 것으로, 더욱 자세하게는 미세조류 배양 중의 배양액에 인산염을 추가하여 전단응력을 최소화하면서 용존산소량을 일정하게 유지시켜 고농도의 미세조류를 생산할 수 있는 미세조류 배양방법에 관한 것이다

Chlorella sp. ABC-001 strain having excellent lipid productivity and cell growth rate under high carbon dioxide and salt concentration condition and uses thereof

본 발명은 내염성을 가지며 고농도 이산화탄소 조건에서 잘 자라고, 지질을 많이 축적하는 신규한 클로렐라 속 ABC-001 균주를 제공하는 것이다. 본 발명의 신규한 클로렐라 속 ABC-001 균주는 담수와 염도가 있는 기수 및 해수에서 거의 동일한 세포 생장과 지질 생산성을 보이며 특히, 해수에서 배양했을 시 자연침전으로 수확이 용이하다. 본 발명의 내염성을 가지며 고농도 이산화탄소 조건에서 높은 지질 생산성을 가진 클로렐라 속 ABC-001 균주는 해안에 인접한 발전소 배기가스 내 이산화탄소를 효과적으로 제거할 수 있으며, 바이오매스 생산 및 이를 원료로 사용하여 유용한 물질을 생산하는 공정에 큰 기여를 할 수 있어 관련 산업에 매우 유용하다

RUBBER COMPOSITION FOR TIRE TREAD AND TIRE MANUFACTURED BY USING THE SAME

본 발명은 원료고무 100 중량부, 보강성 충진제 70 내지 120 중량부, 및 미세조류로부터 추출한 오일 10 내지 50 중량부를 포함하는 타이어 트레드용 고무 조성물 및 이를 이용하여 제조된 타이어에 관한 것으로, 타이어의 구름 저항에 의한 에너지 손실을 줄여 차량의 연비를 높이고, 환경오염 물질 배출량을 감소시킬 수 있다