NITROGEN STARVATION INDUCED LIPID ACCUMULATION BY Chlorococcum infusionum (EAU-10) AS POTENTIAL RENEWABLE SOURCE OF LIPID FOR BIODIESEL PRODUCTION

Abstract

Microalgae are organisms effective of accumulating high quantity of industrially important lipids with promising characteristics as an excellent feedstock for biodiesel production. This study assess the possibility of using a green microalga, Chlorococcum infusionum (EAU-10) for biodiesel production by evaluating the growth characteristic, lipid yield and fatty acid profile of the microalga cultivated at varying concentrations of nitrogen source (0.375 - 1.50 g L^-1 NaNO₃). High lipid accumulation was observed in nitrogen-starved cultivation condition (0.375 g L^-1 NaNO₃) after 23 days of growth. Maximum biomass concentration of Chlorococcum infusionum (EAU-10) under nitrogen starved condition is 0.577 ± 0.003 g L^−1 with 21.26% oil content per dry weight of algal biomass and lipid productivity of 22.08 mg L^−1 day^−1. Nitrogen starvation caused an increase in the total oil content and a decrease in biomass production of the microalga. Profiling of fatty acids of the obtained algal biodiesel shows methyl palmitate (C16:0) and methyl nonadecanoate (C19:0) contribute to almost 70% of Chlorococcum infusionum  (EAU-10) fatty acid methyl esters (FAME) profile. Overall, a total of 74.58% of saturated fatty acid (SAFA) methyl ester content is present in the algal lipid, which is exceedingly high in contrast to other similar studies. Analysis of C. infusionum FAME profile in relation to some important fuel properties showed that the algal oil has the potential to produce biodiesel with excellent fuel qualities.