Biological removal of nitrogen oxides by microalgae, a promising strategy from nitrogen oxides to protein production.

Nitrogen oxides (NO) are the components of fossil flue gases that give rise to serious environmental and health hazards. Among the available techniques for NO removal, microalgae-based biological removal of NO (BioDeNO) is a promising and competent technology with eco-friendly path of low energy and low-cost solution for the pollution. In this review article, current biological technologies including bacteria-based and microalgae-related BioDeNO are discussed. Comparing to direct BioDeNO approach, indirect BioDeNO by microalgae is more promising since it is more stable, reliable and efficient. By transforming inorganic nitrogen nutrients to organic nitrogen, microalgae can potentially play an important role in converting NO into high-value added products. The microalgae-based BioDeNO process displays an attractive prospect for flue gas treatment to reduce environmental NO pollution and potentially supply protein products, establishing an efficient circular-economy strategy.