Fatty acid profile and energy efficiency of biodiesel production from an alkaliphilic algae grown in the photobioreactor

Abstract

In order to gain insight into biodiesel production, suitability of an alkaliphilic green algae (Chlorellla vulgaris) was evaluated experimentally and by conducting an energy analysis. Biomass productivity was 28–31 mg-L−1- d−1 and lipid production reached the maximum of 38% of the algal biomass. At a low light intensity (60–90 μmol/m2/s), the specific growth rate showed a cyclic behavior. At a higher light intensity (240–280 μmol/m2/s), the growth rate was almost constant and more biomass was produced as compared to the low light intensity. Lipid analyses after transesterification showed that the major fractions of fatty acids were C16:0, C 18:1 and C18:2. A minute amount of trans isomer (which is very rare in the eukaryotic cells) was also detected during initial lipid accumulation phase. From the energy analysis, it was found that biodiesel production using this strain algae could be energy efficient, if biomass drying was facilitated by waste heat.