Light Intensity Improves Growth, Lipid Productivity, and Fatty Acid Profile of Chlorococcum oleofaciens (Chlorophyceae) for Biodiesel Production

The present study was aimed to consider the effect of light intensity on the growth and lipid accumulation properties of a freshwater microalga Chlorococcum oleofaciens KF584224.1. The microalga was cultivated at five different light intensities of 50, 100, 200, 400, and 800 mu mol photons m(-2) s(-1) for 20 days. The culture curves illustrated the fastest growth rate for microalgae illuminated with 200 mu mol photons m(-2) s(-1), while the longest exponential growth curve was obtained in culture illuminated with 400 mu mol photons m(-2) s(-1). Once algae reached the stationary phase, the maximum biomass productivity (367.82 +/- 21.63 mg L-1 day(-1)) was found in culture illuminated with 200 mu mol photons m(-2) s(-1), while the highest lipid content (59.18 +/- 1.62%) and lipid productivity (126.72 +/- 3.27 mg L-1 day(-1)) were achieved in culture illuminated with 400 mu mol photons m(-2) s(-1). The ratio of saturated fatty acids significantly increased with enhancing light illumination, while the ratio of monounsaturated fatty acids and polyunsaturated fatty acids tend to decline (p < 0.05). The properties of biodiesel obtained from C. oleofaciens cultured under 50 mu mol photons m(-2) s(-1) met the specifications provided by the international biodiesel standards (European EN 14214 and US ASTM D6751), higher light illumination improved the biodiesel quality. Findings of the present study demonstrated that light intensity could improve the lipid productivity and biodiesel properties obtained from C. oleofaciens as a potential feedstock for biofuel production, especially under 400 mu mol photons m(-2) s(-1) light intensity.