化学
亚硝酸盐
一氧化二氮
铵
羟胺
无机化学
环境化学
氧化剂
电子受体
亚硝酸
生物量(生态学)
氮气
光化学
有机化学
生态学
硝酸盐
生物
作者
Michelle N. Young,Joshua P. Boltz,Bruce E. Rittmann,Ahmed Al‐Omari,José Jiménez,Imre Takács,Andrew K. Marcus
标识
DOI:10.1021/acs.est.1c08498
摘要
Nitrous oxide (N2O) is a greenhouse gas emitted from wastewater treatment, soils, and agriculture largely by ammonium-oxidizing bacteria (AOB). While AOB are characterized by being aerobes that oxidize ammonium (NH4+) to nitrite (NO2-), fundamental studies in microbiology are revealing the importance of metabolic intermediates and reactions that can lead to the production of N2O. These findings about the metabolic pathways for AOB were integrated with thermodynamic electron-equivalents modeling (TEEM) to estimate kinetic and stoichiometric parameters for each of the AOB's nitrogen (N)-oxidation and -reduction reactions. The TEEM analysis shows that hydroxylamine (NH2OH) oxidation to nitroxyl (HNO) is the most energetically efficient means for the AOB to provide electrons for ammonium monooxygenation, while oxidations of HNO to nitric oxide (NO) and NO to NO2- are energetically favorable for respiration and biomass synthesis. The respiratory electron acceptor can be O2 or NO, and both have similar energetics. The TEEM-predicted value for biomass yield, maximum-specific rate of NH4+ utilization, and maximum specific growth rate are consistent with empirical observations. NO reduction to N2O is thermodynamically favorable for respiration and biomass synthesis, but the need for O2 as a reactant in ammonium monooxygenation likely precludes NO reduction to N2O from becoming the major pathway for respiration.
科研通智能强力驱动
Strongly Powered by AbleSci AI