Nitrogen removal and metabolic profiling of a cold-adaptive and biofilm producing paddy soil bacterium Cupriavidus sp. PDN31

ABSTRACTTo assess the physiology and low temperature adaptability of the key players of nitrification and denitrification, denitrifying bacteria were isolated and characterized from the selected paddy fields. Bacterial strains belonging to Cupriavidus and Ochrobactrum sp. were explored through the selective screening of heterotrophic nitrifying and aerobic denitrifying bacteria. The direct implication of nitrate removal in the natural sample was estimated by taking the nitrate supplemented soil as well as the enriched culture. A more prominent cold-adaptive bacterium was identified as Cupriavidus sp. PDN31. The utilization of ammonium, nitrate, and nitrite and the presence of nitrous oxide reductase (nosZ) gene, catalyses the first step of the denitrification conferred its heterotrophic nitrification and aerobic denitrification ability. The ammonium, nitrate, and nitrite removal efficiency of PDN31 was found to be 92.1%, 93.5%, and 99.8%, respectively. The functional traits, evaluated from metabolizing va...