Effects of Temperature and Nitrogen Concentration on Growth and Lipid Accumulation of the Green Algae Chlorella vulgaris for Biodiesel

Abstract

This study investigated the effect of different temperatures and different nitrogen concentrations on the lipid content and biomass of Chlorella microalgae. In this study, algae were cultured in five media with different amounts NaNO3 as 3, 1.5, 0.80, 0.40 g/L, and three temperatures (10, 20, 30 °C). The results of the experiments showed that the optimal temperature and nitrogen concentration for the biomass increase in Chlorella vulgaris are 30°C and 3 g/L, respectively. It was observed that biomass decreased and lipid amount increased due to the decrease in nitrogen concentration. The high lipid amount of 20.80% dry weight (DW) was obtained from the algae produced at 30°C in the free-nitrate medium. The contribution of temperature change to lipid production was not as effective as nitrogen deficiency in the study. According to the fatty acid analysis results made by GC-FID, C. vulgaris seems suitable for biodiesel production because it contains medium-length (C16-C18) fatty acid chains.