Freshwater algal species consortia exhibit optimal biomass and biodiesel production under calcium chloride and magnesium sulphate stress

Microalgae have been pioneering microbial cell factories for sustainable bioenergy production and other high-value product extraction. The present study affirms using mixed algal species (MAS) as a consortium for escalated biomass yield and lipid production under different calcium chloride and magnesium sulphate concentrations toward biofuel production. Of the different concentrations of Ca and Mg concentrations tested, 75 mg/L of calcium and 125 mg/L of magnesium displayed maximal biomass yield, cell density, and biomass productivity. The optimization revealed 18 days of day-light incubation for enhanced biomass and biochemical production. Further, a higher lipid content of 24.55% was noticed at 0 mg/L Ca, while a maximum lipid content of 22-23.2% was observed from the MAS grown in 100 and 125 mg/L Mg concentrations. Regarding the biodiesel yield from MAS, 0 mg/L Ca showed a higher biodiesel yield of 68.45%, while 65.62-68.33% was obtained from 75 mg/L and 125 mg/L Mg concentrations. In addition, the biodiesel produced from the high Ca concentration showed higher unsaturated fatty acids of 55.13%, whereas biodiesel obtained from a higher Mg - amended consortium presented high saturated fatty acids of 53.12%. The present work will enable environmental scientists to combinatorial benefits for utilizing microalgal consortium for circular bionomy aspects and attaining sustainable development goals. Moreover, the present attempt aims to assess the microalgal consortium-based - biodiesel production in accomplishing Sustainable Development Goal - 7 (clean and affordable energy) as enlisted by the UNSDG 2030 agenda.