Microalgal Cd resistance and its exertions on pigments, biomass and lipid profiles

Abstract

This study highlights freshwater oleaginous microalgae as efficient vectors for development of eco-friendly environmental solutions. An effective hybrid approach has been presented here for cadmium tolerance complementing with enhanced lipid productivity in four freshwater oleaginous microalgae viz., Chlorella singularis, Chlorella sorokiniana, Chlorella minutissima and Scenedesmus abundans that can be utilized for bioremediation as well as biofuel generation. All the microalgae displayed considerable resistance to cadmium under in-vitro culture conditions. The identified microalgae presented here can be used for both, Cd contaminated wastewater treatments as well as lipid reservoirs for biofuel production as indicated by their cadmium optimum growth concentration and Maximum Tolerable Concentration (MTC). The biomass and lipid accumulation was not inhibited by Cd, instead it increased under the influence of lower concentrations of cadmium. However, very high concentrations of Cd (>300 mg/L) inhibited both biomass and lipid yield. A decrease in all the photosynthetic pigments was recorded in the presence of Cadmium (Cd) at various concentrations. The GC–MS based lipid profiles indicated the dominance of SAFA and MUFA under the stress of Cd.