Bio-refinery approaches based concomitant microalgal biofuel production and wastewater treatment

Abstract

Adopting the biorefinery approaches on the coupled process of phycoremediation and biofuel production using freshwater microalgae. A green microalga, Scenedesmus sp., cultivated in various concentrations of domestic wastewater (0, 20, 40, 60, 80, 100%v/v). Maximum biomass productivity was obtained 62 mg/L/day cultivated in 100%v/v wastewater. During the stationary phase, the biomass was harvested adopting the flocculation technique. Interestingly, Scenedesmus sp., preferentially utilized 71.2% nitrate, 89.6% phosphorus, 23.5% calcium, 2% magnesium, 97.7% sulphate, 30% ammonia, 10.9% chloride, and 15.2% alkalinity in the wastewater which contribute to the wastewater treatment. Lipid productivity was found to be 19 mg/L/day. The fatty acid profile of transesterified lipids was characterized by adopting FT-IR, GC–MS, and 1H NMR. The extracted biomass was utilized for the feedstock for bioethanol production. The amount of reducing sugar was found to be 11.2% (w/v). Acid hydrolyzed reducing sugars subjected to fermentation using Saccharomyces cerevisiae NCIM3288. Bioethanol was found to be 10.4 g/L after distillation.