25 years’ research on microalgae and its lesson

Microalgae, photosynthetic microorganisms, can be observed under a microscope, have an ecological function as a primary producer in an aquatic ecosystem and are estimated to be composed of over 40,000 species. Especially, the cyanobacteria are seems to be the oldest organisms appeared in the ancient planet. As a consequence of gradual industrialization, increased population and urbanization, water systems become more eutrophic and occasionally show microalgal bloom called as red tide and green tide resulted in detrimental effect on water quality, sudden death of aquaculture fish, etc. Our research has focused on the ecophysiological characterization of eutrophication in Daechung Reservoir, control of cyanobacterial bloom, monitoring of cyanobacterial bloom by molecular techniques and mathematical modelling. Especially, our ultrasonic technology for the reduction of cyanobacterial bloom has been officially authorized as a New Environmental Technology by the Ministry of Environment in 2007. At the beginning of the 21st century, global warming caused by increased CO2 concentration in the atmosphere was become one of key environmental issues all over the world. Also, the oil price was as high as $147/bbl in 2008 and then that was acted as a trigger to develop renewable energy including algae biofuel. At this time, our research team was carrying out the biological fixation of CO2 by microalgae and production of biodiesel from their biomass. This can be considered as a representative green technology which can reduce environmental contamination and concomitantly stimulate economic growth. Our research includes the isolation of indigenous microalgae, molecular improvement of microalgae, mass cultivation in photobioreactor and raceway pond, harvesting with bioflocculant and transesterification of oil to biodiesel. Through last 25-years' research on microalgae, we are preserving over 200 species, about 1,200 indigenous microalgal strains which are an important genetic resources and some of them are available to researchers in academia, industries and research institutes. Finally, the lesson based on the 25-years' research experience with microalgae can be emphasized on specialty, creativity and convergency for high scientific achievements.