1.Department of Civil & Environmental Engineering,The Hong Kong University of Science and Technology,Hong Kong,China;2.State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering,Tongji University,Shanghai,China;3.Institute for Advanced Study,The Hong Kong University of Science and Technology,Hong Kong,China;4.Hong Kong Branch of the Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution,The Hong Kong University of Science and Technology,Hong Kong,China;5.Wastewater Treatment Laboratory, FYT Graduate School,The Hong Kong University of Science and Technology,Guangzhou,China
Abstract:
Nitrous oxide (N2O), a potent greenhouse gas, is emitted during nitrogen removal in wastewater treatment, significantly contributing to greenhouse effect. Nitrogen removal generally involves nitrification and denitrification catalyzed by specific enzymes. N2O production and consumption vary considerably in response to specific enzyme-catalyzed nitrogen imbalances, but the mechanisms are not yet completely understood. Studying the regulation of related enzymes’ activity is essential to minimize N2O emissions during wastewater treatment. This paper aims to review the poorly understood related enzymes that most commonly involved in producing and consuming N2O in terms of their nature, structure and catalytic mechanisms. The pathways of N2O emission during wastewater treatment are briefly introduced. The key environmental factors influencing N2O emission through regulatory enzymes are summarized and the enzyme-based mechanisms are revealed. Several enzymebased techniques for mitigating N2O emissions directly or indirectly are proposed. Finally, areas for further research on N2O release during wastewater treatment are discussed.
