This study investigated implications of nitrogen limitation and sufficiency on the Acetyl Co-A carboxylase activity for stimulating lipid productivity in marine Chlorella vulgaris (JF894250). To identifying optimal nitrogen concentration the effect of N-limitation and N- sufficient conditions (0.36 to 142.86 mM) on growth and lipid accumulation of C. vulgaris was investigated. Maximum biomass production, specific growth rate of C. vulgaris was recorded (0.19 gL-1day) during cultivation with an initial nitrate concentration of 142.86 mM. However, the maximum total lipid content was 113.46 mg/g of C. vulgaris on dry weight basis and neutral lipid was 61.29 μg eq triolein/ml in wet sample with 0.36 mM nitrate and the lipid productivity of 0.0094 gL−1day−1 was achieved with 0.36 mM nitrate. Correspondingly the lipid contents the fatty acids like C16:0, C18:0, C18:1 showed a clear effect viz. o viz. with N-limited condition. Hitherto the of ACCase contents of microalgae was strongly influenced by the variation of nitrogen concentration. The investigation also elucidated the direct response of acetyl co-A carboxylase (Accase) to N- limitation-sufficient conditions on the lipid accumulation in Chlorella vulgaris. Correspondingly the lipid content and the saturated fatty acids which contributes the major part of biodiesel was recorded a 90.42% of the total fatty acids under N-Limted conditions (0.36 Mm nitrate) while which showed a lucid expression of effect of which working hand in hand (vis o vis) of ACCase contents of microalgae was strongly influenced by the variation of nitrogen concentration.