Effect of light intensity on algal growth in designed hybrid photobioreactor and biodiesel production

Abstract

In current scenario algal fuel is considered as the most viable solution for the depleting non-renewable fuel sources. This study demonstrates the controlled, continuous production of the microalgae species Chlorella Pyrenoidosa in a novel designed hybrid photobioreactor aimed to the later production of biodiesel. The reactor is operated at different light intensity and its effect on the biomass production and pH was assessed. The final biomass is harvested by centrifugation preceded by sedimentation from which the algal lipids are extracted using solvent extraction method and biodiesel by acid catalysed transesterification reaction is produced. The species population density is found to be exponential at 7130 LUX at a photoperiod of 8/16(L/D). The biomass growth in the developed design is established as a factor of 2.88 with respect to optical density. At the light intensity of 7130LUX, the developed Hybrid Photobioreactor yields a dry algal mass of 2.09g/L with a lipid productivity of 1.01gL-1day-1 and 70.62% of fatty acid methyl esters (FAME). The analysis of FAME is done using gas chromatography and a maximum of 73.4% biodiesel composition is observed.