Upgrading of microalgal consortia with CO2 from fermentation of wheat straw for the phycoremediation of domestic wastewater

Abstract

Algae have been considered as a best feedstock for combating CO₂. In the present study, two mixed microalgal cultures i.e. MAC1 and MAC2 were evaluated in batch mode with an extraneous supply of CO₂ from the fermentation of wheat straw. Both the mixed cultures displayed promising CO₂ sequestration potentials of 287 and 263 mg L^-1d^-1, respectively. The removal efficiencies in terms of ammonium, phosphate, chemical oxygen demand, and nitrate were found to be 87%, 78%, 68% and 65%, respectively. Enriching the tolerance of the microalgal consortia to CO₂ supply and wastewater as the nutrient source significantly enhanced the lipid production for both the microalgae consortia. Lipid contents of MAC1 and MAC2 were observed to be 12.29 & 11.37%, respectively while the biomass yield from both the consortia was 0.36 g L^-1. Total chlorophyll and protein contents of MAC1 and MAC2 were 14.27 & 12.28 µgmL^-1 and 0.13 & 0.15 mgmL^-1, respectively. Both the consortia found to have significant potential for CO₂ sequestration, wastewater remediation and biofuel production.

Keywords: CO(2) sequestration; Fermentation; Mixed microalgal culture; Phycoremediation; Sewage treatment.