Optimization Of Chlorella Lipid Production Using Metabolic Flux Analysis

Biodiesel is playing a more important role in the field of novel energy research. these years,productions of biodiesel are developing rapidly with primary materials of bean, waste edible oil andpalm but without microalgae which is not widely utilized for technical limitation and lack of essentialresearch of microalgae metabolism. In this thesis, the heterotrophic culture of Chlorella and themetabolic flux analysis of its lipid biosynthesis were performed.Result showed that the summit of Chlorella growth occurred at12days after culture started.NaNO3at0.5g/L turned out the lowest specific growth rate of0.731. The highest lipid content ofChlorella cells occurred at12days after culture started. The lipid content of the12th day varied from21.6%to32.%when NaNO3concentration decreased from0.5g/L to0.125g/L.According to literatures of Chlorella lipid biosynthesis, a metabolic network of Chlorella lipidbiosynthesis was constructed, containing EMP with7reactions, HMP with2reactions, TCA with5reactions and fatty acid biosynthesis with11reactions. In the metabolic flux analysis, the fluxes of EMP,HMP and TCA were found rising with the falling of NaNO3concentration. Comparison of differentgrowth period suggested that metabolic fluxes of fatty acid biosynthesis of12days after culture startedwere much higher than that of initial period, and the optimizing lipid content of38.9%were obtained atthe same time.