Accelerating innovation in nitrogen removal bioprocesses through the study of the emerging properties of natural microbial communities of nitrifiers.

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Brief description of the context of the research including potential impact:Nitrogen is a fundamental constituent of any form of life: it is necessary for the synthesis of amino acids (building blocks of proteins) and nucleic acids. Although the atmosphere of Earth is composed of 78% dinitrogen (N2), this cannot be assimilated by plants or animals. For this reason, the nitrogen cycle on Earth is essential to any environment because through biological and geochemical processes all the chemical forms of nitrogen are balanced, promoting the existence of diverse ecosystems. Owing to human activity, the nitrogen cycle is unbalanced in many environments. These include natural water bodies where discharge of domestic and industrial waters happens. More often, favored by the global rise of temperatures, the accumulation of NH4+ and organic forms of nitrogen facilitates the presence of algae blooms that can be toxic to animals and humans. Together, the accumulation of specific nitrogen forms in natural waters reduces their environmental diversity and increases NO and N2O emissions, inducing ozone depletion and contributing to climate change.To balance the nitrogen cycle in the environment, the reduction of nitrogen discharges to water bodies is fundamental. A sustainable way of doing this is using natural microbial communities able to catalyze the transformation of inorganic and organic forms of nitrogen dissolved in water. Bioprocesses aim to control the activity of these communities towards the production of N2 gas. However, the effectiveness of these processes is compromised by our lack of understanding of the microorganisms that control the nitrogen cycle. Before, canonical nitrification was always considered to be carried by two specific functional groups and denitrification by heterotrophic bacteria. However, in the last decades, the knowledge about the biological nitrogen cycle has dramatically change. For instance, the discovery of anaerobic ammonia oxidation (Anammox), the isolation of archaea able to perform ammonia oxidation as ammonia-oxidizing bacteria (AOA and AOB), the isolation of a Nitrospira specie capable to perform the complete ammonia oxidation (Comammox) and the understanding of denitrification and its microbial community have happen in the last 50 years. All this new knowledge permitted the enhance of the biological wastewater treatment process, reducing the emission of N2O and the consumption of oxygen. But also, new scientific questions have raised: How is possible that AOB and AOA co exist in the same environment if both carry out the same biological process? How does this coexistence affect nitrification and denitrification at natural and engineering process? Which is the niche differentiation between AOB and AOA at natural environments?Aims and objectives:The objective of this project is to explore the above scientific questions analyzing the current information in the literature, collecting the kinetic parameters of nitrifiers and developing state-of-the-art mathematical models to describe their growth. These models will study the effect of environmental conditions such as pH, temperature or salinity over the microbial activity and ultimately over the bioengineered process. This theoretical analysis will be verified and validated through experiments developed here at the Division of Water and Environment of the University of Glasgow. The aim will be to accelerate innovation in bioprocesses being able to propose novel solutions for nitrogen removal in water streams (waste or/and drinking water treatments). Novelty of the research methodology:We are going to use comprehensive mathematical models able to describe microbial activity in detail and its impact in the local environment at the microscale level. This will be used to predict the performance of bioprocesses function on controlled operational conditions and the characteristics of the influent treated. These mathematical models