Scenedesmus dimorphus and Scenedesmus quadricauda : two potent indigenous microalgae strains for biomass production and CO2 mitigation - A study on their growth behavior and lipid productivity under different concentration of urea as nitrogen source.

Abstract

Microalgae are fast growing biological systems which are capable of fixing high amount of carbon dioxide through photosynthesis to produce biomass. The two fresh water microalgae strains, Scenedesmus dimorphus and Scenedesmus quadricauda were selected for this study. Both the algal strain were cultivated in different concentrations of urea as nitrogen source in the growth medium. The concentration of urea at which maximum growth rate in terms of biomass and lipid productivity obtained was at 0.1g/L urea in case of both the strains. The maximum increase in biomass per day and lipid content for Scenedesmus dimorphus was found to be 1.523 mg/L/day and 34% in terms of dry cell weight with a specific growth rate of 0.54 /day of and for Scenedesmus quadricauda it was 1.266 mg/L/day and 31% in terms of dry cell weight with a specific growth rate 0.392 /day. It was observed that when urea concentration was increased beyond 0.1g/L, the biomass and cell number decreased gradually and both strains showed a lower lipid productivity.