Investigation of the effect of solar irradiation and temperature on biomass production of h. pluvialis in photobioreactors under outdoor cultivation in Sri Lanka

Abstract

Complicated and changeable weather conditions and contamination from fungi, protozoa and bacteria increase difficulties in outdoor microalgae cultivation. In this paper, outdoor microalgae cultivation was investigated in Moratuwa city, Western province Sri Lanka. During December, when both the solar irradiation and temperature is high, the water spray system combined two agro shading nets, each with a shading rate of 40-50% can effectively reduce the temperature to 27±2 0C and control solar irradiation below 13500 lux in the 3 L vertical tubular photobioreactor. Under an initial biomass density of 0.2 g/l and an atmospheric air flowrate of 1 vvm, H. pluvialis had a maximum biomass accumulation of 0.45 g/l and the maximum specific growth rate of 0.020 g/l.day. In addition, reactor system and its design exhibited good performance, implying a potential scale- up opportunity.