Selective Enrichment of Comammox Nitrospira in a Moving Bed Biofilm Reactor with Sufficient Oxygen Supply

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

27 Scopus Citations
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Author(s)

  • Jing Zhao
  • Min Zheng
  • Zicheng Su
  • Tao Liu
  • Jie Li
  • Jianhua Guo
  • Shihu Hu

Detail(s)

Original languageEnglish
Pages (from-to)13338-13346
Journal / PublicationEnvironmental Science and Technology
Volume56
Issue number18
Online published1 Sept 2022
Publication statusPublished - 20 Sept 2022
Externally publishedYes

Abstract

The recent discovery of comammox (complete ammonia oxidation) Nitrospira has upended the long-held nitrification paradigm. Although comammox Nitrospira have been identified in wastewater treatment systems, the conditions for their dominance over canonical ammonia oxidizers remain unclear. Here, we report the dominance of comammox Nitrospira in a moving bed biofilm reactor (MBBR) fed with synthetic mainstream wastewater. Integrated 16S rRNA gene amplicon sequencing, fluorescence in situ hybridization (FISH), and metagenomic sequencing methods demonstrated the selective enrichment of comammox bacteria when the MBBR was operated at a dissolved oxygen (DO) concentration above 6 mg O2/L. The dominance of comammox Nitrospira over canonical ammonia oxidizers (i.e., Nitrosomonas) was attributed to the low residual ammonium concentration (0.02-0.52 mg N/L) formed in the high-DO MBBR. Two clade A comammox Nitrospira were identified, which are phylogenetically close to Candidatus Nitrospira nitrosa. Interestingly, cryosectioning-FISH showed these two comammox species spatially distributed on the surface of the biofilm. Moreover, the ammonia-oxidizing activity of comammox Nitrospira-dominated biofilms was susceptible to the oxygen supply, which dropped by half with the DO concentration decrease from 6 to 2 mg O2/L. These features collectively suggest a low apparent oxygen affinity for the comammox Nitrospira-dominated biofilms in the high-DO nitrifying MBBR. © 2022 American Chemical Society.

Research Area(s)

  • comammox Nitrospira, complete ammonia oxidation, metagenomics, moving bed biofilm reactor, oxygen affinity

Citation Format(s)

Selective Enrichment of Comammox Nitrospira in a Moving Bed Biofilm Reactor with Sufficient Oxygen Supply. / Zhao, Jing; Zheng, Min; Su, Zicheng et al.
In: Environmental Science and Technology, Vol. 56, No. 18, 20.09.2022, p. 13338-13346.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review