Modeling and experimental investigation of growth and lipid kinetics in the marine microalga Chlorella sp. for biodiesel production

The green microalga Chlorella sp. is a suitable candidate for biodiesel production due to its high lipid yield. Its specific growth rate increases with light intensity, while a maximum lipid content of 35.29% was achieved during the stationary phase under stress conditions (high light intensity and nitrogen limitation), approximately 4.5-fold higher than under standard conditions. Four kinetic models were evaluated, and the Logistic model was selected for its simplicity and good agreement with the experimental growth rate. Under stress conditions, the fatty acid profile consisted mainly of myristic (C14:0; 12%), lauric (C12:0; 17%), palmitic (C16:0; 26%), and oleic acids (C18:1; 28%). In contrast, palmitic acid dominated under standard conditions (C16:0; 61%), indicating good biodiesel quality from Chlorella sp.