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https://hdl.handle.net/2115/87916

NH2OH Disproportionation Mediated by Anaerobic Ammonium-oxidizing (Anammox) Bacteria

英語

up-flow column reactor

2022

Japanese Society of Microbial Ecology, Department of Bioresource Science

Microbes and environments

37(2)

ME21092

Anammox bacteria produce N-2 gas by oxidizing NH4+ with NO2-, and hydroxylamine (NH2OH) is a potential intermediate of the anammox process. N-2 gas production occurs when anammox bacteria are incubated with NH2OH only, indicating their capacity for NH2OH disproportionation with NH2OH serving as both the electron donor and acceptor. Limited information is currently available on NH2OH disproportionation by anammox bacteria; therefore, the stoichiometry of anammox bacterial NH2OH disproportionation was examined in the present study using N-15-tracing techniques. The anammox bacteria, Brocadia sinica, Jettenia caeni, and Scalindua sp. were incubated with the addition of (NH2OH)-N-15, and the production of N-15-labeled nitrogenous compounds was assessed. The anammox bacteria tested performed NH2OH disproportionation and produced 1(5-15)N(2) gas and NH4+ as reaction products. The addition of acetylene, an inhibitor of the anammox process, reduced the activity of NH2OH disproportionation, but not completely. The growth of B. sinica by NH2OH disproportionation (-240.3 kJ mol NH2OH-1 under standard conditions) was also tested in 3 up-flow column anammox reactors fed with 1) 0.7 mM NH2OH only, 2) 0.7 mM NH2OH and 0.5 mM NH4+, and 3) 0.7 mM NH2OH and 0.5 mM NO2-. NH2OH consumption activities were markedly reduced after 7 d of operation, indicating that B. sinica was unable to maintain its activity or biomass by NH2OH disproportionation.

学術雑誌論文

Version of Record

1342-6311