Potential of Dictyosphaerium sp. LC172264 Concomitant Remediation of Cassava Wastewater and Accumulation of Lipids for Biodiesel Production

Abstract

As a way of making algal feedstock feasible for biofuel production, simultaneous utilization of microalga Dictyosphaerium sp. LC172264 for cassava wastewater remediation and accumulation of lipids for biodiesel production was investigated. The algal biomass, lipid contents and composition were measured from the autotrophic, heterotrophic and mixotrophic cultured algal cells. Physicochemical parameters of the cassava wastewater and bioremediation potentials were measured. Biodiesel properties were deduced and compared with the standards. The results showed that mixotrophic culture was the best for both biomass accumulation (1.022 g/L) and lipid contents (24.53%). Irrespective of the culture condition, the predominant fatty acids were similar and included 11-Octadecenoic acid (vaccenic acid (C19H36O2), oleic acid (C18H34O2) and 14-methyl pentadecanoic acid (isopalmitic acid (C17H34O2). The percentage reduction of total dissolved solids was 79.32% and 89.78% for heterotrophy and mixotrophy respectively. Biochemical oxygen demand was 72.95% and 89.35%, chemical oxygen demand was 72.19% and 84.03% whereas cyanide contents reduced from the initial value of 450 mg/L to 93.105 (79.31%) and 85.365 mg/L (81.03%) respectively. Dictyosphaerium sp. showed good growth and lipid production under mixotrophic condition and produced good quality biodiesel under the three cultivation modes. Even though both mixotrophic and heterotrophic conditions had good promise of cassava wastewater remediation by Dictyosphaerium sp., mixotrophy showed superiority.