Work in the Stein laboratory focuses on the numerous and diverse pathways of inorganic nitrogen and single carbon metabolism in bacteria and archaea. Using the tools of comparative genomics, molecular biology, physiology, and biochemistry we study how microorganisms process nitrogen and methane at the molecular, whole-cell, and ecosystem levels. Our goals are to track the evolution of nitrogen metabolism, predict how and when deleterious nitrogen oxide products are released to the environment, and define linkages between methane and nitrogen metabolism. The greenhouse gas nitrous oxide, the ozone depleting nitric oxide, and the groundwater polluting nitrate are the most significant of the nitrogen oxide pollutants created and released by microbial nitrogen metabolism. Single carbon metabolism, i.e. methane oxidation and carbon fixation, are intimately connected to the biogeochemical nitrogen cycle. By interrogating the linkages between single carbon and nitrogen metabolism, we can harness microorganisms to generate commercially viable bioproducts using single-carbon waste streams as feedstocks. We can also maximize microbial activities to increase productivity of vertical agriculture aquaponics systems without production of greenhouse gases.nitrification, N-cycle, single-carbon metabolism, methanotrophy, greenhouse gases, climate change, bioconversions, genomics, genome scale metabolic model, microbial physiology