The objectives of this study are to find the robust strains for the centrate cultivation system and to evaluate the effect of environmental factors including light intensity, light-dark cycle, and exogenous CO 2 concentration on biomass accumulation, wastewater nutrient removal and biodiesel production. The results showed that all 14 algae strains from the genus of Chlorella, Haematococcus, Scenedesmus, Chlamydomonas, and Chloroccum were able to grow on centrate. The highest net biomass accumulation (2.01g/L) was observed with Chlorella kessleri followed by Chlorella protothecoides (1.31g/L), and both of them were proved to be capable of mixotrophic growth when cultivated on centrate. Environmental factors had significant effect on algal biomass accumulation, wastewater nutrients removal and biodiesel production. Higher light intensity and exogenous CO 2 concentration with longer lighting period promote biomass accumulation, biodiesel production, as well as the removal of chemical oxygen demand and nitrogen, while, lower exogenous CO 2 concentration promotes phosphorus removal.
Bibliographical noteFunding Information:
The authors wish to thank the University of Minnesota Initiative for Renewable Energy and the Environment (IREE), Metropolitan Council Environmental Services (MCES), Xcel Energy, and the Legislative-Citizen Commission on Minnesota Resources (LCCMR) for the financial support. The authors also wish to extend their appreciation to Blanca C. Martinez for providing help in the labs and Adam Sealock of Saint Paul MCES Wastewater Treatment Plant for helping with the centrate collection.
- Algae cultivation
- Biodiesel production
- Centrate wastewater
- Environmental factors
- Mixotrophic growth