Potential of wastewater grown algae for biodiesel production and CO2 sequestration

Abstract

Algae have been proposed as a potential renewable fuel source. Photosynthetic CO₂ fixation to substrates that can be converted to biodiesel by microalgae is thought to be a feasible technology with energy-saving and environment-friendly approach. In the present study, potential of microalgae, from wastewater stabilization pond, as a feedstock for biodiesel production and CO₂ sequestration was evaluated. Mixed algae sample showed the highest CO₂ fixation rate, followed by Chlorella sp., Scenedesmus incrassatulus, Scenedesmus dimorphus and Chroococcus cohaerens (2.807, 1.627, 1.501, 1.270 and 0.786 g L^-1 d^-1, respectively). Nile red stain was used for detection of lipid in microalgal sample which was further extracted and analysed by gas chromatography (GC). The main fatty acids present in the mixed algae sample were fatty acids with C14–C18 (>98%) that are generated after natural CO₂ sequestration. At ambient CO₂ concentration, total fatty acid methyl esters (FAME) mainly comprised of myristic acid (C14:0), 0.0718%; palmitic acid (C16:0), 2.558%; octadecenoic acid (C18:1), 28.98% and linoleic acid (C18:2), 12.54% which makes the microalgal biomass a suitable feedstock for biodiesel production and CO₂ mitigation.

Keywords: Biodiesel, carbon dioxide fixation, fatty acid profile, microalgae, wastewater stabilization pond

African Journal of Biotechnology Vol. 12(20), pp. 2939-2948