Biodiesel production potential of an indigenous South African microalga, Acutodesmus bajacalifornicus

Abstract

In this study, a South African indigenous microalga Acutodesmus bajacalifornicus was evaluated in different cultivation media. Eleven potential cultivation media were identified and tested on A. bajacalifornicus, a potential source for biodiesel production. A. bajacalifornicus had the highest growth rate in the JG medium (in-house formulation), with a competitive average specific growth rate of 0.47 d-1. The highest biomass productivity was in the Hase medium, but with relatively low productivity of 53.1 mg.L-1.d-1. Analysis of the biomass lipid content and profile of each cell culture, using fatty acid methyl ester (FAME) gas chromatography (GC) showed that the lipid content varied between cultivation media, with minimum lipid content of 20% (w/w) and an average close to 47% (w/w). Utilising biodiesel property predictive formulas, and the lipid profiles obtained in this study, it was possible to predict the properties of biodiesel that could be generated from A. bajacalifornicus. It was found that biomass from eight of the media adhered to South African summer grade biodiesel standards. As such, A. bajacalifornicus is a potential candidate for microalgal biodiesel production in South Africa. However, the bioenergy yield rate would need to be improved to have a similar attractiveness to other studies.