Harnessing aquaculture wastewater with Chlorella protothecoides for biodiesel and bioethanol production

Abstract

The wastewater treatment potential of the microalga Chlorella protothecoides was investigated in the context of fish farming, and it is efficacy was further evaluated through cultivation at different inoculation levels to gauge pollutant removal efficiency. This study examines C. protothecoides for growth, nutrient removal, and biofuel potential. Climbing perch culture effluent (CPCE) mediums are employed for algal cultivation, with optical density (OD) measurements capturing growth dynamics that culminate on the 10th day in dense biomass accumulation. Nitrogen and phosphorus, key components of wastewater, exhibited substantial reduction. Ammonia concentrations decreased by 77.88%, nitrite by 93.75%, and nitrate by 95.67%. The most striking reduction was observed in phosphorus levels, with a remarkable 97.87% removal rate. Furthermore, the microalga's pigment composition was explored, showcasing high chlorophyll content, alongside significant carotenoids. High protein content (45.71 g/100 g) offers amino acids for bio-based materials and enzymatic catalysts. Carbohydrates (33.23 g/100 g) represent a valuable energy source for bioethanol production. Lipid content (8.64 g/100 g) suggests biodiesel potential, with unsaturated fatty acids comprising over 82% of the biodiesel content. The study underscores C. protothecoides's potential in growth, nutrient removal, and biofuel production. Therefore, this research contributes valuable insights into sustainable wastewater treatment and bioenergy generation technologies, with empirical data supporting the findings.