Characterization of a novel Pseudomoas species for Dissimilatory nitrate reduction to ammonium and denitrification in microaerobic conditions

As the traditional treatment methods for denitration absorption solution has many deficiencies, such as low removal efficiency and complicated process. A process for the treatment of denitration absorption solution was proposed, in which dissimilatory nitrate reduction to ammonium (DNRA) can transform nitrate nitrogen into NH₄⁺–N, and ammonia can be recovered while treating the denitrification absorption solution, thus realizing resource utilization and harmless. A bacteria strain with the abilities of denitrification and DNRA was screened from the anaerobic sludge tank of Henan Lianhua Gourmet Powder Co. Ltd to realize the treatment of denitration absorption solution. The isolated strain was named Pseudomonas sp. DKF based on its phylogenetic characteristics. The effects of dissolved oxygen, carbon source and C/N on the strain were further investigated. The strain could perform DNRA as well as denitrification in both microaerobic and anaerobic condition, and the conversion efficiency was not much different under the two conditions. The best carbon source of Pseudomonas was sodium acetate. The maximum NH₄⁺ generation efficiency of 18.11 ± 0.92% was achieved at C/N was 8 with sodium acetate used as carbon source. The isolated strain can enable the DNRA process, plays an important role in nitrate transformation pathways to recover ammonium salt and provides a new idea for regulating and retaining reactive nitrogen in the ecosystem.