High nitrous oxide (NO) greenhouse gas reduction potential of Pseudomonas sp. YR02 under aerobic condition.

Aerobic environments exist widely in wastewater treatment plants (WWTP) and are unfavorable for greenhouse gas nitrous oxide (NO) reduction. Here, a novel strain Pseudomonas sp. YR02, which can perform NO reduction under aerobic conditions, was isolated. The successful amplification of four denitrifying genes proved its complete denitrifying ability. The inorganic nitrogen (IN) removal efficiencies (NRE) were >98.0% and intracellular nitrogen and gaseous nitrogen account for 52.6-58.4% and 41.6-47.4% of input nitrogen, respectively. The priority of IN utilization was TAN > NO-N > NO-N. The optimal conditions for IN and NO removal were consistent, except for the C/N ratio, which is 15 and 5 for IN and NO removal, respectively. The biokinetic constants analysis indicated strain YR02 had high potential to treat high ammonia and dissolved NO wastewater. Strain YR02 bioaugmentation mitigated 98.7% of NO emission and improved 32% NRE in WWTP, proving its application potential for NO mitigation.