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미세액적 광생물반응기를 활용한 광독립영양배양에서 Chlamydomonas reinhardtii의 성장성 분석
성영준 ( Young Joon Sung ),곽호석 ( Ho Seok Kwak ),최홍일 ( Hong Il Choi ),김영환 ( Jaoon Young Hwan Kim ),심상준 ( Sang Jun Sim ) 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.1
최근 고부가가치 산물의 생산이 가능한 미세조류는 이산화탄소의 생물학적 전환 측면에서 많은 주목을 받고 있다. 그렇지만 미세조류 종 자체가 지닌 낮은 광합성 효율 및 생산성의 한계는 미세조류를 활용한 공정의 상업화를 막는 장애요인이다. 따라서 본 연구에서는 대표 미세조류 Chlamydomonas reinhardtii의 광독립영양 성장성 분석을 위한 미세액적 광생물반응기를 개발하였다. PDMS 기반의 미세유체 칩 내에 미세기둥을 배열하고 미세챔버의 높이를 조절하여 미세액적 내 이산화탄소의 전달속도를 증가시켰으며, 이는 세포 성장성과 형광 세기 변화를 통해 확인하였다. 마지막으로 미세액적 광생물반응기를 활용하여 다양한 이산화탄소 농도 및 광량 조건에서 C. reinhardtii의 광독립영양배양에서 성장성을 96 시간동안 관찰하고 분석하였다. 본 연구 결과를 통해 미세액적 광생물반응기는 성장성 및 유용물질 생산성이 우수한 미세조류 종을 빠르게 분석하고 쉽게 분리할 수 있는 효율적인 플랫폼임을 입증하였다. Recently, microalgae which can produce high-value products have attracted increasing attention for biological conversion of CO<sub>2</sub>. However, low photosynthetic efficiency and productivity have limited the practical use of microalgae. Thus, we developed microdroplet photobioreactor for the analysis of photoautotrophic growth of model alga, Chlamydomonas reinhardtii. CO<sub>2</sub> transfer rate was increased by integrating micropillar arrays and adjusting height of microchamber. These results were identified by change of cell growth rate and fluorescence intensity. Lastly, the photoautotrophic growth kinetics of C. reinhardtii in microdroplet photobioreactor were investigated under different CO<sub>2</sub> concentrations and light intensities for 96 hours. As a result, microdroplet photobioreactor was efficient platform for isolation and rapid evaluation of microalgal strains which have enhanced productivity of high-value products and growth performance.
Microdroplet photobioreactor for the photoautotrophic culture of microalgal cells
Sung, Young Joon,Kim, Jaoon Young Hwan,Bong, Ki Wan,Sim, Sang Jun The Royal Society of Chemistry 2016 The Analyst Vol.141 No.3
<P>Microalgae, unicellular photoautotrophic microorganisms, have attracted great attention for the production of biofuel and high-value products, but the commercial use of microalgae has been limited by low photosynthetic productivity. To overcome this limitation, it is required to develop an efficient platform for the rapid evaluation of photoautotrophic growth performance and productivity of microalgal strains. Here we describe a droplet-based photobioreactor for high-throughput analysis of the photoautotrophic growth of microalgal cells. By integrating micropillar arrays and adjusting the height of the microchamber, we could accurately monitor the growth kinetics of microalgae in an immobilized microdroplet and improve the transfer rate of CO2 into the microdroplet photobioreactor with an increased contact area between the microdroplet and PDMS surface. The improvement of CO2 transfer into the microdroplet was also confirmed by improved microalgal cell growth and a decrease in pH measured using colorimetric and fluorescence-based assays. The photoautotrophic growth kinetics of Chlorella vulgaris were measured under different CO2 concentrations (ambient, 1%, 2.5%, 5% and 7.5%) and light intensity (35, 55, 100, 150, and 200 mu mol photons per m(2) per s) conditions, which are key factors for photoautotrophic growth. Chlorella vulgaris in a microdroplet showed better cell growth performance compared to a flask culture due to the reduced shading effects and improved mass transfer. Finally, we could evaluate the photoautotrophic growth performance of four microalgal strains (Chlorella vulgaris, Chlorella protothecoides, Chlorella sorokiniana and Neochloris oleoabundans) for 120 hours. These results demonstrate that our microdroplet system can be used as an efficient photobioreactor for the rapid evaluation of the photoautotrophic growth of microalgal strains under various conditions.</P>
Recent progress in hydrogenase and its biotechnological application for viable hydrogen technology
차형준,Jaoon Young Hwan Kim 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.1
Despite increasing interest in hydrogen (H2) as an alternative energy carrier, the current production of H2still depends on fossil fuels. Biotechnological hydrogen production can provide a more sustainable way to generate H2. Hydrogenases are key enzymes involved in hydrogen metabolism of microorganisms with roles of H2 oxidation or evolution. They have potential applications in H2 production in vivo, in vitro and fuel cell. Important achievements have been made over the past decade in our understanding of hydrogenase and its biotechnological application as catalyst for H2 production and fuel cell. This review summarizes recent progress in the study of hydrogenases, involving strategies for biosynthesis, maturation process, isolation of novel hydrogenases, heterologous expression system, structural feature of oxygen (O2)-tolerant hydrogenases, and biotechnological applications for viable H2 technology.
Multiplex microfluidic system integrating sequential operations of microalgal lipid production
Kwak, Ho Seok,Kim, Jaoon Young Hwan,Na, Sang Cheol,Jeon, Noo Li,Sim, Sang Jun The Royal Society of Chemistry 2016 The Analyst Vol.141 No.4
<P>The unit cost for the production of algal biofuel needs to be reduced in order to be a substitute for fossil fuel. To achieve this goal, the development of a novel system is needed for a rapid screening of numerous microalgal species to isolate superior strains with the highest lipid productivity. Here, we developed a PDMS-based multiplex microfluidic system with eight chambers and micropillar arrays to expedite multiple steps for lipid sample preparation from different microalgal strains. We could rapidly and efficiently perform sequential operations from cell culture to lipid extraction of eight different microalgal strains simultaneously on a single device without harvesting and purification steps, which are labor-and energy-intensive, by the simple injection of medium and solvent into the central inlet due to the integrated micropillar arrays connecting the chambers and central inlet. The lipid extraction efficiency using this system was comparable (94.5-102.6%) to the conventional Bligh-Dyer method. We investigated the cell growth and lipid productivity of different strains using the microfluidic device. We observed that each strain has a different lipid accumulation pattern according to stress conditions. These results demonstrate that our multiplex microfluidic approach can provide an efficient analytical tool for the rapid analysis of strain performances (e.g. cell growth and lipid productivities) and the determination of the optimal lipid induction condition for each strain.</P>
Synergistic effect of multiple stress conditions for improving microalgal lipid production
Kwak, Ho Seok,Kim, Jaoon Young Hwan,Woo, Han Min,Jin, EonSeon,Min, Byoung Koun,Sim, Sang Jun Elsevier 2016 Algal research Vol.19 No.-
<P><B>Abstract</B></P> <P>This increasing consumption of fossil fuels and emission of greenhouse gases causes climate change. Thus, the development of alternative energy sources such as biofuel is necessary. Microalgae have been spotlighted as renewable energy resources because the potential for producing biofuels from CO<SUB>2</SUB>. However, the unit cost for the production of algae-based biofuel must be reduced for commercialization compared to the petroleum. The optimization of culture conditions of microalgal strains is crucial to increase lipid production for economically viable biofuels. We rapidly analyzed the combined effect of various stress conditions (nitrogen starvation, temperature, pH, and salt concentration) on the lipid production in various strains using a multiplex microfluidic system, enabling multiple operations from cell culture to lipid extraction of different strains. We found the lipid productivity was enhanced by 25 to 54% under combinations of two stress condition compared to the single stress condition. However, the combination of more than three stress conditions reduced the lipid productivities of all microalgal strains because of more stressful environment to the cells compared to the combinations of two stress conditions. We further validated the synergistic effect of combined stress conditions in flask culture with the increases in lipid productivities by up to 106% compared to the single stress condition. We also observed that fatty acids composition, which influences the quality of algal biofuels, was changed according to the combination of stress conditions. In particular, <I>C. protothecoides</I> can be good candidate for production of high quality of biodiesel, because it has high CN, IV and low CFPP which is suitable for high quality of biodiesel. These results indicate that combination of multiple stress conditions can be efficient strategy for the optimization of microalgal cultivation to produce algal biofuels with high quality and economic feasibility.</P>
Polyamine-Functionalized Polydiacetylene (PDA) Vesicles for Colorimetric Sensing of Carbon Dioxide
김경우,이정민,권용민,최태영,Jaoon Young Hwan Kim,배승섭,송종암 한국고분자학회 2018 Macromolecular Research Vol.26 No.3
Ocean acidification resulting from anthropogenic CO2 has led to severe threats to marine biodiversity and ecosystems. Therefore, an effective CO2 sensing system is necessary for marine environment monitoring. In this study, polyaminefunctionalized polydiacetylene was synthesized via the conjugation of 10,12-tricosadiynoic acid (TRCDA) monomers with diethylenetriamine (DETA), and its capability for CO2 detection was demonstrated. The structure of TRCDA-DETA was confirmed using nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry. Then, the colorimetric and fluorogenic responses of TRCDA-DETA vesicles were examined by applying CO2. A specific color transition with a colorimetric response (CR%) of 34.39±1.46 was observed within 3 min of CO2 exposure as well as detecting fluorescent response upon CO2 detection coincidently. These results indicated that TRCDA-DETA vesicles can be an effective tool for CO2 detection, and their unique properties may have potential applications in multiple fields.