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Ammonium transformed into nitrous oxide via nitric oxide by Pseudomonas putida Y-9 under aerobic conditions without hydroxylamine as intermediate

Author:
Huang, Xuejiao, Xu, Yi, He, Tengxia, Jia, Hongjie, Feng, Mi, Xiang, Shudi, Wang, Shutong, Ni, Jiupai, Xie, Deti, Li, Zhenlun
Source:
Bioresource technology 2019 v.277 pp. 87-93
ISSN:
0960-8524
Subject:
Pseudomonas putida, aerobic conditions, ammonia monooxygenase, ammonium, gene amplification, hydroxylamine, nitric oxide, nitrites, nitrous oxide, oxidation, total nitrogen
Abstract:
Previous studies have reported that hydroxylamine (NH2OH) is an inevitable intermediate of the ammonium (NH4+) oxidation pathway under aerobic conditions. In this study, Pseudomonas putida Y-9 was found to oxidize ammonium into N2O via NO without the accumulation of NH2OH and NO2− under aerobic conditions. NH2OH was nearly completely transformed into NO2− whether NH4+ was present in the medium, and NH4+ could accelerate the transformation of NH2OH to NO2− by promoting Y-9 growth. NH4+ was oxidized rapidly by Y-9 with or without the presence of NH2OH in the medium, and the decrease of total nitrogen reached 30.65 mg/L and 39.38 mg/L, respectively, which indicates that NH2OH inhibits the transformation efficiency of NH4+ to N2O. Gene amplification and enzyme assays demonstrated that ammonia monooxygenase doesn’t exist in Y-9. All results show that NH4+ can be transformed into N2O via NO by Y-9 under aerobic conditions without NH2OH as intermediate.
Agid:
6292773