Enhanced production of fatty acids via redirection of carbon flux in marine microalga Tetraselmis sp

Lipids in microalgae are energy-rich compounds and considered as an attractive feedstock for biodiesel production. To redirect carbon flux from competing pathways to the fatty acid synthesis pathway of Tetraselmis sp., we used three types of chemical inhibitors, which can block the starch synthesis pathway or photorespiration, under nitrogen-sufficient and nitrogen-deficient conditions. The starch synthesis pathway in chloroplasts and the cytosol can be inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethylurea and 1,2-cyclohexanediamine tetra acetic acid, respectively. Degradation of glycine into ammonia during photorespiration was blocked by -(carboxymethyl) hydroxylamine hemihydrochloride to maintain biomass concentration. Inhibition of starch synthesis pathways in the cytosol by 1,2-cyclohexanediamine tetra acetic acid increased fatty acid productivity by 27% under nitrogen deficiency, whereas the blocking of photorespiration in mitochondria by -(carboxymethyl) hydroxylamine hemihydrochloride was increased by 35% under nitrogen-sufficient conditions. The results of this study indicate that blocking starch or photorespiration pathway may redirect carbon flux to fatty acid synthesis.