Deciphering the role of comammox bacteria in nitrogen removal systems

Northeastern University, Boston MA

Investigators

Abstract

Nitrification is a chemical reaction process that plays an important role in the removal of organic nitrogen from municipal wastewater. Nitrification is also an energy intensive process. The recent discovery of a single organism (the comammox bacterium: COMplete AMMonia OXidiser) that can perform nitrification, has led to research into whether this bacterium may be useful for creating a less energy intensive process for nitrogen removal from wastewater. The ability to manage comammox impact on nitrogen removal is critically dependent on a fundamental understanding of its ecology, physiology, and engineering relevance. This research project advances our understanding of the comammox bacterium by developing novel, scalable, and quantitative methods for its characterization. The project goals are being accomplished by coupling state-of-the-art molecular, bioinformatics, and statistical methods with laboratory and field experiments. This project is yielding fundamental insights into comammox bacterial importance, ecology, and physiology and informing process strategies to exploit this novel organism for sustainable nitrogen removal in wastewater treatment plants. The research plan is integrated with a comprehensive suite of educational outreach activities involving undergraduate, graduate, and K-12 students. The activities include a blend of bioinformatics training for undergraduate and graduate students, mentoring of researchers from underrepresented minority groups, and modules for K-12 students on wastewater treatment. Ensuring the effectiveness and sustainability of nitrogen removal from wastewater requires a detailed understanding of its biotransformation pathways. The recent discovery of comammox bacterium represents a paradigm shift in the understanding of aerobic nitrification, the first key step in nitrogen removal. The research team is investigating the ecology, physiology, and engineering relevance of the comammox bacterium in four key nitrogen removal process configurations. A primary objective of the project is to develop novel methods to characterize the abundance, diversity, and activity of comammox bacteria in complex microbial communities. A deeper understanding of the impact of process and environmental conditions on comammox bacteria will lead to improved strategies to manage and manipulate their contribution in nitrogen removal. Results of this project are advancing our understanding of the role and relevance of novel comammox bacteria within complex nitrifying communities.