A sustainable bioeconomy approach for improved biodiesel production using photocatalytic GO@CN assisted cultivation of Chlorosarcinopsis sp. MAS04

Low biomass yield and lipid production limits the development of microalgae-derived biodiesel on a wide scale. However, the use of photo-responsive nanomaterials as a substrate for microalgae can resolve these issues and enhance its economic viability. The current investigation highlights the potential of graphene oxide; graphitic carbon nitride (GO@CN) as a photocatalytic material for Chlorosarcinopsis sp. MAS04. A suite of characterization techniques including Scanning electron microscope (SEM), X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and Zeta potential was used to perceive the structural, morphological, and stability insights of the synthesized nanocomposite. Cytotoxicity assay for 96 h was performed for testing microalgal viability. Subsequently, microalgae cultures were supplemented with 0-200 mg L-1 of synthesized nano -composite for 30 days. The intracellular reactive oxygen species (ROS) concentration was estimated to determine the oxidative stress burden. The incurred cellular lipids were processed into fatty acid methyl esters (FAMEs) possessing suitable biodiesel characteristics. The 50 mg L-1 of the optimal supplement of GO@CN for microalgae cultivation results in the highest biomass and lipid production of 3.825 g L-1 and 38.5% respectively, that is a 1.5-fold increase in biomass and nearly a 1.9-fold rise in lipid content, compared to the control. Additionally, a cost-benefit analysis of the developed process inferred a 350% increase in FAME yield at an expense of 0.15 g/ INR more than the cost estimated for the control. Thus, this amalgamation of nano-algal science could be a prospective approach for augmenting microalgae-based biodiesel as a sustainable bioeconomy.