Microalgae-based nitrogen bioremediation

Pollution poses an increasing threat to the environment and to human health. Nitrogen pollution is of great concern, with nitrogen oxide (NOx) in the air and ammonia nitrogen in water being two major pollutants. Culturing microalgae in NOx or wastewater with high concentrations of ammonia nitrogen would both reduce environmental pollution and provide a source of nitrogen for microalgal culture. However, for microalgae-based bioremediation to be feasible, many fundamental questions about algal biology must be addressed. This review summarizes progress in microalgal biotransformation, outlines applications of this technology, and provides an in-depth description of the current state of microalgae-based bioremediation of NOx or wastewater with high concentrations of ammonia nitrogen. Furthermore, we present possible solutions to some of the obstacles that must be overcome to realize the practical applications of microalgae-based bioremediation. • NOx in the air and ammonia nitrogen in water are two major nitrogen pollutants. • Microalgae-based bioremediation of NOx or ammonia nitrogen get more attention. • Progress in microalgal biotransformation of NOx or ammonia nitrogen is summarized. • The practical application cannot yet be realized and much work remains to be done. • Although this technology still faces great challenges, it has a promising future.