Abstract
Anaerobic ammonium oxidation coupled to nitrite reduction (termed as Anammox) was demonstrated as an efficient pathway to remove nitrogen from a wastewater treatment system. Recently, anaerobic ammonium oxidation was also identified to be linked to iron(III) reduction (termed Feammox) with dinitrogen, nitrite, or nitrate as end-product, reporting to enhance nitrogen removal from the wastewater treatment system. However, little is known about the role of Anammox bacteria in the Feammox process. Here, slurry from wastewater reactor amended with ferrihydrite was employed to investigate activity of Anammox bacteria in the Feammox process using the 15N isotopic tracing technique combined with 16S rRNA gene amplicon sequencing. A significantly positive relationship between rates of 15N2 production and iron(III) reduction indicated the occurrence of Feammox during incubation. Relative abundances of Anammox bacteria including Brocadia, Kuenenia, Jettenia, and unclassified Brocadiaceae were detected with low relative abundances, whereas Geobacteraceae dominated in the treatment throughout the incubation. 15N2 production rates significantly positively correlated with relative abundances of Geobacter, unclassified Geobacteraceae, and Anammox bacteria, revealing their contribution to nitrogen generation via Feammox. Overall, these findings suggested Anammox bacteria or cooperation between Anammox bacteria and iron(III) reducers serves a potential role in Feammox process.
Highlights
IntroductionFeammox [anaerobic ammonium oxidation coupled to iron(III) reduction] is a pathway of nitrogen cycling identified recently and makes a contribution to nitrogen loss in various environments, such as terrestrial (e.g., wetland, tropical rainforest, and paddy soils) and aquatic ecosystem (e.g., freshwater and marine) in addition to denitrification, co-denitrification, and anaerobic ammonium oxidation (Clement et al, 2005; Yang et al, 2012; Ding et al, 2014, 2017, 2019; Huang and Jaffé, 2014; Zhou et al, 2016)
Feammox [anaerobic ammonium oxidation coupled to iron(III) reduction] is a pathway of nitrogen cycling identified recently and makes a contribution to nitrogen loss in various environments, such as terrestrial and aquatic ecosystem in addition to denitrification, co-denitrification, and anaerobic ammonium oxidation (Clement et al, 2005; Yang et al, 2012; Ding et al, 2014, 2017, 2019; Huang and Jaffé, 2014; Zhou et al, 2016)
Anammox bacteria such as Brocadiaceae, Kuenenia, and Jettenia and iron(III) reducers including Geobacter and unclassified Geobacteraceae were found potentially involved in the Feammox process
Summary
Feammox [anaerobic ammonium oxidation coupled to iron(III) reduction] is a pathway of nitrogen cycling identified recently and makes a contribution to nitrogen loss in various environments, such as terrestrial (e.g., wetland, tropical rainforest, and paddy soils) and aquatic ecosystem (e.g., freshwater and marine) in addition to denitrification, co-denitrification, and anaerobic ammonium oxidation (Clement et al, 2005; Yang et al, 2012; Ding et al, 2014, 2017, 2019; Huang and Jaffé, 2014; Zhou et al, 2016). Anammox bacteria, including members of the Planctomycetales such as Brocadia, Kuenenia, Anammoxoglobus, Jettenia, Anammoximicrobium moscowii, and Scalindua (Rikmann et al, 2014), possesses a versatile metabolism involved in the utilization of diverse electron donors (e.g., NH4+ and propionate) and acceptors (e.g., NO2−, NO3−, and SO42−) (Strous et al, 2002; Cervantes et al, 2009; Rikmann et al, 2014; Rios-Del Toro and Cervantes, 2016; Rios-Del Toro et al, 2018). Inspired by these recent findings, we hypothesized that Fe(III) can play as terminal electron acceptors in anaerobic ammonium oxidation mediated by Anammox bacteria in the sludge from a wastewater treatment reactor
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
