Environment International ( IF 10.3 ) Pub Date : 2021-03-25 , DOI: 10.1016/j.envint.2021.106528 Qi Sheng 1 , Ming Yi 1 , Yujie Men 2 , Huijie Lu 1
17α-ethynylestradiol (EE2) is a priority emerging contaminant (EC) in diverse environments that can be cometabolized by ammonia oxidizing bacteria (AOB). However, its transformation kinetics and the underlying molecular mechanism are unclear. In this study, kinetic parameters, including maximum specific EE2 transformation rate, EE2 half-saturation coefficient, and EE2 transformation capacity of AOB were obtained by using the model AOB strain, Nitrosomonas europaea 19718. The relationship between EE2 cometabolism and ammonia oxidation was divided into three phases according to reducing power availability, namely “activation”, “coupling”, and “saturation”. Specifically, there was a universal lag of EE2 transformation after ammonia oxidation was initiated, suggesting that sufficient reducing power (approximately 0.95 ± 0.06 mol NADH/L) was required to activate EE2 cometabolism. Interestingly, nitric oxide emission increased by 12 ± 2% during EE2 cometabolism, along with significantly upregulated nirK cluster genes. The findings are of importance to understanding the cometabolic behavior and mechanism of EE2 in natural and engineered environments. Maintaining relatively high and stable reducing power supply from ammonia oxidation can potentially improve the cometabolic removal of EE2 and other ECs during wastewater nitrification processes.
中文翻译:
硝化细菌对17α-乙炔雌二醇的新陈代谢取决于降低电力供应并导致一氧化氮形成增加
17α-乙炔基雌二醇(EE2)是各种环境中的优先出现的污染物(EC),可被氨氧化细菌(AOB)代谢。但是,其转化动力学和潜在的分子机理尚不清楚。在这项研究中,动力学参数,包括最大的特定EE2转化率,EE2半饱和系数和 AOB的EE2转化能力, 是通过使用模型AOB菌株,欧洲亚硝化单胞菌获得的。19718.根据电力供应的减少,EE2代谢和氨氧化之间的关系分为三个阶段,即“激活”,“耦合”和“饱和”。具体而言,启动氨氧化后EE2转化普遍滞后,这表明激活EE2代谢需要足够的还原力(约0.95±0.06 mol NADH / L)。有趣的是,在EE2代谢过程中,一氧化氮的排放增加了12±2%,同时nirK明显上调簇基因。这些发现对于理解自然环境和工程环境中EE2的代谢行为和机制具有重要意义。维持相对较高和稳定的氨氧化还原电源可以潜在地改善废水硝化过程中EE2和其他EC的代谢分解。