Potential enhancement of biodiesel production from microalgae- Temperature effect on lipid production of two species of microalgae

Abstract

In an effort to screen and enhance the potential production of biodiesel from marine microalgae, we have investigated the effect of growth temperature on the lipid production and composition of two selected algal species, Chattonella ovata and Prorocentrum micans. Algae were grown at the same condition except for the temperature (four different temperature conditions: 15, 20, 25, and 30°C), and harvested in early or late stationary growth phases. The growth patterns of cultures were similar between two species under the same temperature conditions except for the timing of the stationary phase and the final cell density. P. micans reached the stationary phase 10 days later than C. ovata at 15 and 20°C. As we expected, the slowest growth rates were found at the highest temperature condition (30°C) for both species cultures. For C. ovata, lipid levels were linearly and rapidly decreased with temperature increases. On the other hand, lipid contents of P. micans were linearly increased with temperature increases until 25°C and then rapidly decreased at 30°C. The fatty acid compositions of both species were also significantly changed with temperature increases. Specially, polyunsaturated fatty acids (41.3 % of total fatty acids) were most abundant at 15 and 25°C for C. ovata and P. micans, respectively, at which lipid levels were highest. But under the highest temperature condition (30°C), saturated fatty acids (43.8 % of total fatty acids) were the most dominant fatty acid group (>40% of total fatty acids) for both species with the lowest lipid levels. The preliminary results indicate that these algal species could synthesize different components of lipid and differently accumulate lipids in their cell under different growth condition (i.e., temperature). Therefore, the cultural conditions are one of the most important factors to produce more and better quality of potential bioenergy from marine algae.