Nitrification/denitrification shaped the mercury-oxidizing microbial community for simultaneous Hg0 and NO removal

[Display omitted] •The Hg0-oxidizing microbial community was shaped by nitrification/denitrification.•Dominant genera acted as Hg0 oxidizers, nitrifiers and denitrifiers simultaneously.•Characterization of biofilm confirmed the formation of Hg2+ from mercury oxidation.•Mechanism of mercury oxidation...

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Bibliographic Details
Published in:Bioresource technology 2019-02, Vol.274, p.18-24
Main Authors: Huang, Zhenshan, Wei, Zaishan, Xiao, Xiaoliang, Tang, Meiru, Li, Bolong, Zhang, Xiao
Format: Article
Language:English
Subjects:
Hg0 bio-oxidation
Mechanism
Membrane biofilm reactor
Microbial community
Nitrification/denitrification
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Summary:[Display omitted] •The Hg0-oxidizing microbial community was shaped by nitrification/denitrification.•Dominant genera acted as Hg0 oxidizers, nitrifiers and denitrifiers simultaneously.•Characterization of biofilm confirmed the formation of Hg2+ from mercury oxidation.•Mechanism of mercury oxidation and nitrification/denitrification was proposed. A denitrifying/nitrifying membrane biofilm reactor for simultaneous removal of Hg0 and NO was investigated. Hg0 and NO removal efficiency attained 94.5% and 86%, respectively. The mercury-oxidizing microbial community was significantly shaped by nitrification/denitrification after the supply of gaseous Hg0and NO continuously. Dominant genera Rhodanobacter and Nitrosomonas participated in Hg0 oxidation, nitrification and denitrification simultaneously. Hg0 oxidizing bacteria (Gallionella, Rhodanobacter, Ottowia, Nitrosomonas and etc.), nitrifying bacteria (Nitrosomonas, Rhodanobacter, Diaphorobacte and etc.) and denitrifying bacteria (Nitrosomonas, Rhodanobacter, Castellaniella and etc.) co-existed in the MBfR, as shown by metagenomic sequencing. X-ray photoelectron spectroscopy (XPS) and high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS) confirmed the formation of a mercuric species (Hg2+) from mercury bio-oxidation. Mechanism of mercury oxidation can be described as the bacterial oxidation of Hg0 in which Hg0 serves as electron donor, NO serves as electron donor in nitrification and electron acceptor in denitrification, oxygen serves as electron acceptor.
ISSN:0960-8524
1873-2976
DOI:10.1016/j.biortech.2018.11.069