Nitrous oxide-sink capability of denitrifying bacteria impacted by nitrite and pH
Nitrous oxide-sink capability of denitrifying bacteria impacted by nitrite and pH
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DOI：
10.1016/j.cej.2021.132402
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发表时间：
2022-01
影响因子：
15.1
通讯作者：
Yiwen Zhou;Shuting Zhao;T. Suenaga;Megumi Kuroiwa;Shohei Riya;A. Terada
中科院分区：
文献类型：
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作者：
Yiwen Zhou;Shuting Zhao;T. Suenaga;Megumi Kuroiwa;Shohei Riya;A. Terada
一氧化二氮（N2O）是一种强效的温室气体和臭氧消耗物质，在反硝化过程中产生和消耗。评估完全反硝化细菌的N2O生产和消耗活动对于了解它们在工程系统中通过亚硝酸盐（NO2−）经济有效地去除氮的N2O汇能力至关重要。然而，这些n2o还原菌（N2ORB）的生理机制尚不清楚。本研究旨在评价两种N2ORB，Azospirasp的生理特性。菌株I13和反硝化镰刀杆菌菌株I51。采用A15N示踪法测定了NO2−和N2O共存条件下N2O的生产和消耗活动。两种N2ORB均表现出较高的N2O消耗率（RN2ObyAzospirasp）。在初始NO2−浓度为2.14 mmol-N L−1且外源添加N2O的情况下，菌株I13和alicycliphilus反硝化菌株I51、23.85和7.60 μmol-N mg-biomass - 1h−1的N2O产率（PN2O、5.88和1.32 μmol-N mg-biomass - 1h−1）高于N2O的产率（PN2O、5.88和1.32 μmol-N mg-biomass - 1h−1），表明N2ORB起到了N2O的吸收作用。当NO2−浓度从0.36 mmol-N L−1增加到7.14 mmol-N L−1时，两种N2ORB的净N2O消耗率（= RN2O-PN2O）均下降；azospirasp的下降幅度更大。菌株I13优于菌株I51。酸性条件下NO2−生成游离亚硝酸（FNA）明显影响N2ORB的N2O汇活性。较高的FNA浓度降低了N2ORB的ro_n2o，造成了pH为6和高NO2−浓度下N2O排放的风险。我们的结果显示了氮唑螺的pH和NO2−浓度范围。菌株I13有望作为N2O汇用于通过NO2−快速脱氮。
Nitrous oxide (N2O) is a highly potent greenhouse gas and ozone-depleting substance, produced and consumed during denitrification. Evaluation of the N2O production and consumption activities of complete denitrifying bacteria is essential for understanding their capacity to act as N2O sinks in engineered systems for cost-effective nitrogen removal via nitrite (NO2−). However, the physiologies of these N2O-reducing bacteria (N2ORB) are poorly understood. This study aimed to evaluate the physiologies of two N2ORB,Azospirasp. strain I13 andAlicycliphilus denitrificansstrain I51. A15N tracer method was applied to determine N2O production and consumption activities in the co-presence of NO2−and N2O. Both N2ORB displayed a higher N2O consumption rate (RN2ObyAzospirasp. strain I13 andAlicycliphilus denitrificansstrain I51, 23.85 and 7.60 μmol-N mg-biomass−1h−1, respectively) than N2O production rate (PN2O, 5.88 and 1.32 μmol-N mg-biomass−1h−1, respectively) at an initial NO2−concentration of 2.14 mmol-N L−1with exogenous addition of N2O, indicating that these N2ORB acted as N2O sinks. On increasing the NO2−concentration from 0.36 to 7.14 mmol-N L−1, the net N2O consumption rateRO_N2O(=RN2O–PN2O) decreased for both N2ORB; the magnitude of the decrease was greater forAzospirasp. strain I13 than forAlicycliphilus denitrificansstrain I51. The formation of free nitrous acid (FNA) from NO2−in acidic conditions noticeably affected the N2O sink activities of the N2ORB. A higher FNA concentration decreasedRO_N2Ofor both N2ORB, creating the risk of N2O emission at pH 6 and high NO2−concentration. Our results show the ranges of pH and NO2−concentration whereAzospirasp. strain I13 is promising for use as an N2O sink in shortcut nitrogen removal via NO2−.