Isolation of Four Diatom Strains from Tidal Mud toward Biofuel Production

Development and utilization of bio-energy is an important way to relieve the pressure of global energy shortage. Biodiesel can be a focus of the bio-energy, because it is a cleaner-burning and renewable fuel. Micro algae have been considered to be an ideal source of biodiesel for its high growth rate and high lipid content. Benthic diatoms in tidal mud are considered to be new candidate for obtaining high lipid content micro algal strains although they have not been well noticed. The purpose of this study is getting the diatom strains with high-lipid content from tidal mud toward biofuel production. With microtubule method, four diatom strains were successfully isolated from the tidal mud located in Haicang, Xiamen. They are Navicula halophila, Nitzschia frustulum var. symbiotica, Amphora coffeaeformis, and Nitzschia closterium. The characteristics of morphology, ecology, and distribution of each species are described in the present paper with images of light microscope and electron microscope. Diatoms were cultured in the laboratory and the lipid content of each strain was determined. The lipid content (% dried weight) of the four diatoms are: Navicula halophila 39.1%, Nitzschia frustulum var. symbiotica 35.7%, Amphora coffeaeformis 26.1%, and Nitzschia closterium 18.9%. The result indicates that the lipid content of diatoms from tidal mud is relatively higher compared to the strains from seawater which can be a good source candidate of micro algal biodiesel.