Pilot scale wastewater treatment, CO <sub>2</sub> sequestration and lipid production using microalga, <i>Neochloris aquatica</i> RDS02
Silambarasan Tamil Selvan, V. Balasubramanian, Dhandapani Ramamurthy, Sendilkumar Balasundaram, Kanimozhi Sivamani
Abstract
In present investigation carried out large-scale treatment of tannery effluent by the cultivation of microalgae, Neochloris aquatica RDS02. The tannery effluent treatment revealed that significant reduction heavy metals were chromium-3.59, lead-2.85, nickel-1.9, cadmium-10.68, zinc-4.49, copper-0.95 and cobalt-1.86 mg/L on 15th day of treatment using N. aquatica RDS02. The microalgal biosorption capacity qmax rate was Cr-88.66, Pb-75.87, Ni-87.61, Cd-60.44, Co-52.86, Zn-84.90 and Cu-54.39, and isotherm model emphasized that the higher R2 value 0.99 by Langmuir and Freundlich kinetics model. The microalga utilized highest CO2 (90%) analyzed by CO2 biofixation and utilization kinetics, biomass (3.9 mg/mL), lipid (210 mg mL−1), carbohydrate (102.75 mg mL−1), biodiesel (4.9 mL g−1) and bioethanol (4.1 mL g−1). The microalgal-lipid content was analyzed through Nile red staining. Gas chromatography mass spectrometric (GCMS) analysis confirmed that the presence of a biodiesel and major fatty acid methyl ester (FAME) profiling viz., tridecanoic acid methyl ester, pentadecanoic acid methyl ester, octadecanoic acid methyl ester, myristic acid methyl ester, palmitic acid methyl ester and oleic acid methyl ester. Fourier transform infrared (FTIR) analysis confirmed that the presence of a functional groups viz., phenols, alcohols, alkynes, carboxylic acids, ketones, carbonyl and ester groups. The bioethanol production was confirmed by high-performance liquid chromatography (HPLC) analyze.