Hydroxylamine-dependent anaerobic ammonium oxidation (anammox) by "Candidatus Brocadia sinica".
Although metabolic pathways and associated enzymes of anaerobic ammonium oxidation (anammox) of 'Ca. Kuenenia stuttgartiensis' have been studied, those of other anammox bacteria are still poorly understood. NO2- reduction to NO is considered to be the first step in the anammox metabolism of 'Ca. K. stuttgartiensis', however, 'Ca. Brocadia' lacks the genes that encode canonical NO-forming nitrite reductases (NirS or NirK) in its genome, which is different from 'Ca. K. stuttgartiensis'. Here, we studied the anammox metabolism of 'Ca. Brocadia sinica'. (15) N-tracer experiments demonstrated that 'Ca. B. sinica' cells could reduce NO2- to NH2 OH, instead of NO, with as yet unidentified nitrite reductase(s). Furthermore, N2 H4 synthesis, downstream reaction of NO2- reduction, was investigated using a purified 'Ca. B. sinica' hydrazine synthase (Hzs) and intact cells. Both the 'Ca. B. sinica' Hzs and cells utilized NH2 OH and NH4+, but not NO and NH4+, for N2 H4 synthesis and further oxidized N2 H4 to N2 gas. Taken together, the metabolic pathway of 'Ca. B. sinica' is NH2 OH-dependent and different from the one of 'Ca. K. stuttgartiensis', indicating metabolic diversity of anammox bacteria.
Department of Civil Engineering, National Institute of Technology, Nagaoka College, Nagaoka, Niigata, 940-8532, Japan.
Mamoru
M
Oshiki
Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Sapporo, Hokkaido, 060-8628, Japan.|Water Desalination and Reuse Center (WDRC), Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology (KAUST),Thuwal, 23955-6900, Saudi Arabia.
Muhammad
M
Ali
Tokyo Engineering Consultants Co., Ltd., Kasumigaseki, Chioyadaku, Tokyo 100-0013, Japan.
Kaori
K
Shinyako-Hata
Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Sapporo, Hokkaido, 060-8628, Japan.
Hisashi
H
Satoh
Division of Environmental Engineering, Faculty of Engineering, Hokkaido University, North-13, West-8, Sapporo, Hokkaido, 060-8628, Japan. sokabe@eng.hokudai.ac.jp.
Satoshi
S
Okabe
D064751:Ammonium Compounds / Q000378:metabolism*; D001421:Bacteria, Anaerobic / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D052837:Chemoautotrophic Growth; D003580:Cytochromes / Q000235:genetics / Q000378:metabolism; D019811:Hydroxylamine / Q000378:metabolism*; D009572:Nitrite Reductases / Q000235:genetics / Q000378:metabolism; D010084:Oxidation-Reduction; D000644:Quaternary Ammonium Compounds / Q000378:metabolism
D064751:Ammonium Compounds; D001426:Bacterial Proteins; D003580:Cytochromes; D000644:Quaternary Ammonium Compounds; D019811:Hydroxylamine; D009572:Nitrite Reductases; C028123:nitrite reductase (NO-forming)