Progress on microalgae biomass production from wastewater phycoremediation: metabolic mechanism, response behavior, improvement strategy and principle

• Carbon, nitrogen and phosphorus metabolic mechanisms of microalgae are elucidated. • Response behaviors of microalgae to major inhibitors in wastewater are dissected. • Improvement strategy for microalgae phycoremediation of wastewater is analyzed. • Challenge and perspective for microalgae cultivation in wastewater are discussed. Wastewater phycoremediation mediated by microalgae provides a viable and promising pathway in term of wastewater disposal and bioenergy generation. However, unsatisfactory performance on biomass yield caused by potential toxicity of wastewater is the main bottleneck to hinder the popularization of microalgae-mediate wastewater phycoremediation technique. Recent works suggest a feasibility strategy to enhancing biomass generation and nutrients removal in wastewater via pretreatment technique. This review critically assesses the progress on enhancing the biomass generation of microalgae cultured in wastewater via pretreatment, mainly relating to the carbon, nitrogen and phosphorus metabolic mechanisms of microalgae, the response behaviors of microalgae toward the major inhibitors in wastewater and the improvement strategies and principles of microalgae cultured in wastewater. Present-day results indicated that further works should be performed to sustainably promote the efficiency and stability of biomass production and nutrients removal. One of the most promising developing directions appears to be integrating the existing or evolving wastewater disposal technologies and microalgae cultivation strategies to mitigate the inhibiting effects of wastewater on microalgae cells but ensure available ratio of nutrients. This review aims to provide more information and references on strategies development for microalgae-mediate wastewater phycoremediation technique.