Kinetic modelling of heterotrophic microalgae culture in wastewater: Storage molecule generation and pollutants mitigation

Cultivating microalgae with wastewater offers a dual-beneficial strategy for the removal of nutrients coupled with the accumulation of valuable bioproducts. However, the dynamic mass flow in heterotrophic algal growth is far less known than autotrophic mode. This study particularly provided a new insight into this process by modelling heterotrophic Chlorella sorokiniana. A consensus model was proposed to describe the temporal change of (i) the carbon, nitrogen, and phosphorus in water, (ii) the algal biomass, (iii) the intracellular carbohydrate and lipid, and their correlation under various conditions simulating the complex wastewater environment. The dynamics for the decrement of ambient carbon and nutrients and the increment of biomass, intracellular carbohydrate and lipid was correlated for the first time. The model was calibrated and validated with experimental data of C. sorokiniana. It therefore provides a theoretical basis for the future scale-up of heterotrophic microalgae culture with complicated real wastewaters.