DNRA Acididesulfobacillus acetoxydans

The aim of this study is to describe the Dissimilatory Nitrate Reduction to Ammonium (DNRA) pathway of an acidophilic sulfate reducing bacterium, Acididesulfobacillus acetoxydans. While encoding a Nar-type nitrate reductase, A. acetoxydans does not encode any of the known nitrite reductases. To identify the enzymes involved in DNRA we performed comparative transcriptomics and proteomics. This was followed by cultivation of A. acetoxydans performing DNRA during which we measured all potential nitrogen intermediates. Several intermediates not previously associated with DNRA were identified. For each identified intermediate, resting cell experiments were performed to investigate the biological transformation of nitrogenous compounds by A. acetoxydans. In summary, we demonstrate that the DNRA pathway of A. acetoxydans proceeds via intermediates not previously associated to DNRA and provide data-driven hypotheses which enzymes might be involved in this DNRA pathway.