Abstract

Prolific algal growth in sewage ponds with high organic loads in the tropical regions can provide cost-effective and efficient wastewater treatment and biofuel production. This work examines the ability of Euglena sp. growing in wastewater ponds for biofuel production and treatment of wastewater. The algae were isolated from the sewage treatment plants and were tested for their nutrient removal capability. Compared to other algae, Euglena sp. showed faster growth rates with high biomass density at elevated concentrations of  ammonium (NH₄-N) and organic carbon (C). Profuse growth of these species was observed in untreated wastewaters with a mean specific growth rate (µ) of 0.28 d^-1 and biomass productivities of 132 mg L^-1 d^-1. The algal culture within a short period of 8 days resulted in the 98% removal of Ammonium- Nitrogen (NH₄-N), 93% of Total Nitrogen (TN) 85% of Ortho Phosphate (OP) 66% of Total Phosphate (TP) and 92% Total Organic Carbon (TOC). Euglenoids achieved a maximum lipid content of 24.6% (wt./wt.) with biomass density of 1.24 g L^-1 (dry wt.). Fourier Transform Infra-Red (FTIR) spectra showed clear transitions in biochemical compositions with increased Lipid/Protein (L/P) ratio at the end of the culture. Gas chromatography and mass spectrometry (GC-MS) indicated the presence of high contents of palmitic, linolenic and linoleic acids (46, 23 and 22% respectively), adding to the biodiesel quality. Good lipid content (comprised of  quality fatty acids), efficient nutrient uptake  and profuse biomass productivity  makes the Euglena sp. as a viable source for biofuel production in wastewaters.

 Keywords    Algal nutrient uptake; Biomass productivity; Euglena; FAME; Lipid; Wastewater