Physiological characterization of anaerobic ammonium oxidizing bacterium ‘Candidatus Jettenia caeni’

Abstract

To date, six candidate genera of anaerobic ammonium-oxidizing (anammox) bacteria have been identified, and numerous studies have been conducted to understand their ecophysiology. In this study, we examined the physiological characteristics of an anammox bacterium in the genus 'Candidatus Jettenia'. Planctomycete KSU-1 was found to be a mesophilic (20-42.5°C) and neutrophilic (pH 6.5-8.5) bacterium with a maximum growth rate of 0.0020 h(-1) . Planctomycete KSU-1 cells showed typical physiological and structural features of anammox bacteria; i.e. (29) N2 gas production by coupling of (15) NH4 (+) and (14) NO2 (-) , accumulation of hydrazine with the consumption of hydroxylamine and the presence of anammoxosome. In addition, the cells were capable of respiratory ammonification with oxidation of acetate. Notably, the cells contained menaquinone-7 as a dominant respiratory quinone. Proteomic analysis was performed to examine underlying core metabolisms, and high expressions of hydrazine synthase, hydrazine dehydrogenase, hydroxylamine dehydrogenase, nitrite/nitrate oxidoreductase and carbon monoxide dehydrogenase/acetyl-CoA synthase were detected. These proteins require iron or copper as a metal cofactor, and both were dominant in planctomycete KSU-1 cells. On the basis of these experimental results, we proposed the name 'Ca. Jettenia caeni' sp. nov. for the bacterial clade of the planctomycete KSU-1.

Immunogold Localization of Key Metabolic Enzymes in the Anammoxosome and on the Tubule-Like Structures of Kuenenia stuttgartiensis

“…In the present study, we showed the intracellular localization of the hydroxylamine oxidoreductase (HAO)-like protein kustc0457/58, hydrazine dehydrogenase (HDH), the NO-producing HAO-like protein HOX, nitrite oxidoreductase (NXR), and hydrazine synthase (HZS) within an anammox cell. All of these proteins are encoded in all presently available anammox genomes and play key roles in anammox catabolism (1,2,(9)(10)(11)(12)(13)(14). The fact that all studied protein complexes were exclusively immunolocalized to the anammoxosome in the present study supported the hypothesis that this cell compartment was a true prokaryotic organelle with a dedicated function.…”

“…Apart from nitrite reductase, all currently available anammox genomes encode close homologs of the proteins described above (2,(9)(10)(11)(12)(13)(14), suggesting that they have the same energy metabolism as K. stuttgartiensis.…”

The evolution of Earth's biogeochemical nitrogen cycle

“…At present, it is unclear whether the essential nitrogen transforming enzymes utilize iron or copper cofactors. Phylogenetic analysis has identified both iron and copper binding domains in the genome of annamox bacteria (Ali et al, 2015), and copper limitation of anammox activity has been observed in the field (Jacquot et al, 2013). The evolutionary history of anammox is also poorly known.…”

Enrichment of ANAMMOX bacteria from conventional activated sludge entrapped in poly(vinyl alcohol)/sodium alginate gel

“…from Ca 'Jettenia sp. ', the characteristics of the maximum specific growth rate (µ max ) and the half-saturation constants (Ks NH4 and Ks NO2 for NH 4 + and NO 2 ‾, respectively) are compared [60]. parameters [1].…”