CO2 fixation and production of biodiesel by Chlorella vulgaris NIOCCV under mixotrophic cultivation

Abstract

In this study, Chlorella vulgaris NIOCCV was cultivated in seafood processing industry wastewater with continuous supply of 5%, 10%, and 20% CO₂. The optimum CO₂ fixation efficiency ( [Formula: see text] ), biomass productivity, specific growth rate (SGR), and lipid content recorded were 0.43 mg L^-1 d^-1, 264.58 ± 8.8 mg L^-1 d^-1, 0.46 d^-1, and 38 ± 2.6% on dry weight basis, respectively at CO₂ supply of 10%. The fatty acid methyl ester-derived biodiesel properties determined at same condition were in compliance with national and international fuel standards. The higher calorific value (HHV) of the resultant biomass was 11.14, 16.41 and 12.83 MJ Kg^-1 for CO₂ enrichment of 5%, 10%, and 20%, respectively. The synergistic environmental benefit of nutrients removal from wastewater is shown as an additional advantage of microalgal cultivation. Thus, integration of algae-based CO₂ fixation with wastewater treatment and biodiesel production may realize microalgal CO₂ capture technology as environmentally sustainable and economically more attractive.

Keywords: Biodiesel; CO(2) fixation; Chlorella vulgaris; Microalgae; Photobioreactor; Wastewater treatment.