저온 생장성이 우수한 분리 미세조류 Tetraselmis sp. 5개주의 생장 패턴 및 지방산 조성 분석

Isolation and Characterization of Five Isolates of Tetraselmis sp. with Rapid Growth Rates in Low Temperatures

Abstract

For successful microalgal biodiesel production, the strain should be selected carefully. Fast growth rate and high fatty acid contents are desired traits for algal biodiesel production. In ocean cultivation of microalgae, seawater temperature slowly changes over seasons, and rotating algal strains in accordance with their optimal temperature could improve overall productivity. Additionally, use of indigenous strain is preferred to alleviate potential impacts on the environment. In this study, five strains of Tetraselmis sp. from nearshore of Youngheung Island, Incheon, Korea, were isolated during winter and characterized for their growth patterns and fatty acid compositions in the low temperatures ($5-15^{\circ}C$). The five strains showed various characteristics in optimal growth temperature, fatty acid contents, and compositions. Compared with a strain of Tetraselmis sp., isolated from Ganghwa island in a previous study, a rapid-growing strain with 237% higher biomass productivity and an oleaginous strain with twice higher fatty acid contents at $10^{\circ}C$ were isolated. The oleaginous Tetraselmis strain showed the highest fatty acid productivity among the strains, having 438% higher productivity than the previous strain. Using the new isolates in the seasons with low seawater temperature would improve microalgal fatty acid productivity in ocean cultivation.

Figure 1. Phylogenetic Analysis of the 18S rDNA of New Tetraselmis sp. Isolates.

Figure 2. Time Profiles of Biomass Concentrations of Tetraselmis sp. Strains at (a) 5°C, (b) 10°C, and (c) 15°C.

Figure 3. Biomass Productivities by the Microalgal Strains and Temperature.

Figure 4. Fatty Acid Contents of the Microalgae at 10°C.

Table 1. Sequences of Primers Used for Amplification of 18S rDNA

Table 2. Fatty Acid Compositions of the Microalgae.