18511: Effect of light intensity on algal biomass accumulation and biodiesel productivity when cultivated in highly concentrated municipal wastewater with species Chlorella kessleri and Chlorella protothecoide

Lighting is one of the most important factors that not only affect the growth and cellular composition of algae cells but also the economic efficiency of the cultivation process of algal biomass. In this research, algae species were cultivated in the centrate, a highly concentrated municipal wastewater stream, for simultaneous wastewater treatment and biodiesel production. The effect of light intensity on biomass growth, wastewater nutrient removal and biodiesel productivity was investigated with algae species Chlorella kessleri and Chlorella protothecoide. The light intensities studied were 0, 15, 30, 60, 120, 200 µmolm^-2s^-1. The results showed that the response of algal growth and biodiesel productivity to the change of light intensity varies with different algae species. The growth and biodiesel productivity of Chlorella kessleri increased with the increase of light intensity from 0 to 120 µmolm^-2s^-1 while further increase of light intensity resulted in decrease of biomass accumulation. For Chlorella protothecoide , both the growth and biodiesel productivity increased with the increase of light intensity from 0 to 200 µmolm^-2s^-1. Both species were capable of wastewater nutrients removal under all lighting conditions with higher removal efficiencies coupling with better biomass accumulation.