Abstract:Biological nitrogen removal (BNR) is the key process in wastewater treatment plants, and mastering the metabolic activity of related microorganisms involved in the nitrogen removal process is of great significance for exploring microbial resources potential and improving the nitrogen removal performance of wastewater treatment plants. In recent years, molecular biology methods develop rapidly and has been widely used to reveal the diversity, structure and potential functional genes of the nitrogen removal microorganisms (especially unculturable microorganisms), allowing the role of microorganisms in wastewater BNR system being better clarified. This review introduces the popular molecular biology methods including 16S rRNA gene sequencing, real-time quantitative PCR, metagenomics, metatranscriptomics, metaproteome, and metabolomics, and summarizes their application in nitrifying bacteria, denitrifying bacteria, complete ammonium oxidizing bacteria, anaerobic ammonia oxidizing bacteria, iron-dependent anaerobic ammonium oxidizing bacteria, sulfate-dependent anaerobic ammonium oxidizing bacteria, and nitrite/nitrate type anaerobic methane oxidizing microorganisms, as well as clarifies their metabolic pathways and enzymatic reactions in the nitrogen cycle. It also prospects the technological breakthroughs of molecular biology methods and their application prospects in wastewater BNR systems from three aspects, the “construction of standard determination approaches”, “combination of different methods and interdisciplinary combination” and “simplification of detection methods”. This review provides a comprehensive understanding of the nitrogen removal microbial community and its structure from a systematic perspective, and points out new research directions for future study on BNR microorganisms in wastewater treatment.
