Bioremediation of Swine Wastewater and Biofuel Potential by using Chlorella vulgaris, Chlamydomonas reinhardtii, and Chlamydomonas debaryana

Abstract

Four commercial microalgae strains of Chlorella vulgaris, Chlamydomonas reinhardtii, Scenedesmus dimorphus and Neochloris oleoabundans, and a local strain of Chlamydomonas debaryana were studied in this research. It's found that S. dimorphus and N. oleoabundans were unable to grow on the swine wastewater. The optimal culture conditions for C. vulgaris and C. reinhardtii were found to be (600 μ mol m -2 s -1 and 25°C) and (300 μ mol m -2 s -1 and 20°C), respectively. The growth kinetics was determined using Optical Density (OD) method and flow cytometry. Under the optimal culture conditions, the highest specific growth rates were found to be 1.336 day -1 and 1.286 day -1 for C. vulgaris and C. reinhardtii, respectively. The removal efficiency of nutrients from the wastewater is a function of microalgae growth. When comparing a local C. debaryana strain with these two commercial strains, the final biomass yields and lipid contents were 1.25 g/L and 15.2% (of the total cell dry weight), 0.86 g/L and 19.7%, and 0.73 g/L and 21.7% for C. vulgaris, C. debaryana and C. reinhardtii, respectively. In addition, the lipids from these microalgal strains contain a variety of fatty acids, which are suitable for the biofuel production.