Improved Strains for Biological Treatment of Wastewater

Nitrogen is one of the most abundant nutrients present in wastewater. The removal of excess nitrogen is a crucial step in wastewater treatment because of its detrimental effects on the human health and environment. Biological nitrogen removal processes are widely used owing to their flexibility and lower operating costs. Nitrosomonas europaea is widely used in the nitrification step of the biological nitrogen removal process. However, these biological treatments are unable to efficiently reduce nitrogen content to the desired low levels required to meet the discharge quality standards that are becoming stringent over time. Two of the main reasons for the lower efficiency of these processes are the low growth and nitrogen removal rates exhibited by N. europaea. Efforts to improve the efficiency of N. europaea are hindered by the lack of information about its integrated metabolic network. In this work we report the first genome-scale metabolic network of N. europaea. The model consists of various metabolic pathways and activities based on the organism's genome annotations and biochemical literature. The model has been validated using growth and nitrite production data taken from the existing literature.