Comparative Evaluation of Biomass Production of Four Different Microalgae in Sewage, Diluted Anaerobic Digestion Effluent, and Corn Steep Liquor Medium

Microalgal biomass is a promising renewable feedstock for producing biofuels and bioplastics. The use of wastewater or food industrial organic waste as a cultivation medium is an economical and sustainable approach to microalgal biomass production. However, the biomass productivity of diverse microalgae cultured in different wastewaters or organic wastes is still not fully understood. This study aimed to confirm the biomass production of various microalgae using different culture media, two wastewaters and an organic waste medium, and to identify an ideal combination of microalgae and wastewater/organic waste medium. The four microalgae Chlorella vulgaris, Chlorella sorokiniana, Euglena gracilis, and Chlamydomonas reinhardtii grew well in sewage, 10% anaerobic digestion effluent, and 5 g/L corn steep liquor (CSL). The four microalgae utilized nitrogen from their culture media for biomass production. Biomass production rates ranged from 0.020 to 0.180 g-dry weight (dw)/L/d. The biomass production rates of the four microalgae species were generally higher in 5 g/L CSL and 10% anaerobic digestion effluent, which contained more nitrogen than sewage. CSL and diluted anaerobic digestion effluent were considered suitable for microalgal cultivation. C. sorokiniana cultured in 5 g/L CSL showed the highest biomass production rate (0.180 g-dw/L/d) in this study.