Autotrophic ammonia-oxidizing bacteria produce nitrous oxide (N(2)O) as a by-product of nitrification or as an intermediate of nitrifier denitrification. In soil incubations, acetylene (C(2)H(2)) and large partial pressures of oxygen (O(2)) are used to distinguish between these sources. C(2)H(2) inhibits ammonia oxidation and should therefore inhibit N(2)O production by both nitrification and n...

Pseudomonas aeruginosa, grown to steric saturation between the cellulose fibers of a filter paper, reduced nitrate or nitrite or both when the cell-filled paper was washed, transferred to phosphate buffer, nitrate, or nitrite or both, and glucose agar plates, and incubated under aerobiosis as resting cells. The biological nature of the reduction was ascertained by the use of nitrate and nitrite...

Analyses of human fecal and ileostomy samples by a method that is sensitive and free from interferences indicate that nitrate and nitrite levels in the intestine are lower than reported pre viously. Fecal nitrate and nitrite concentrations ranged from 0 to 14 fimol/kg (0 to 0.9 ppm) and 5 to 19 /¿mol/kg (0.3 to 0.9 ppm), respectively. Ileostomy samples contained from 0 to 7 jumol/kg (0 to 0.4 ...

The cd1 NiRs (nitrite reductases) are enzymes catalysing the reduction of nitrite to NO (nitric oxide) in the bacterial energy conversion denitrification process. These enzymes contain two distinct redox centres: one covalently bound c-haem, which is reduced by external electron donors, and another peculiar porphyrin, the d1-haem (3,8-dioxo-17-acrylate-porphyrindione), where nitrite is reduced ...

A heterotrophic carbon utilizing microbe (R31) capable of simultaneous nitrification and denitrification (SND) was isolated from wastewater of an Indian slaughterhouse. From an initial COD value of 583.0 mg/L, 95.54% was removed whilst, from a starting NH4 (+)-N concentration of 55.7 mg/L, 95.87% was removed after 48 h contact. The concentrations of the intermediates hydroxylamine, nitrite, and...

Anaerobic oxidation of methane (AOM) with sulfate as terminal electron acceptor has been reported for various environments, including freshwater habitats, and also, nitrate and nitrite were recently shown to act as electron acceptors for methane oxidation in eutrophic freshwater habitats. Radiotracer experiments with sediment material of Lake Constance, an oligotrophic freshwater lake, were per...

Bacillus methylotrophicus strain L7, exhibited efficient heterotrophic nitrification-aerobic denitrification ability, with maximum NH(4)(+)-N and NO(2)(-)-N removal rate of 51.58 mg/L/d and 5.81 mg/L/d, respectively. Strain L7 showed different gaseous emitting patterns from those strains ever described. When (15)NH(4)Cl, or Na(15)NO(2), or K(15)NO(3) was used, results of GC-MS indicated that N(...

Removal of ammonia nitrogen and nitrate nitrogen by an heterotrophic nitrification-aerobic denitrification strain is an economical and effective method. In this article, a kind of heterotrophic nitrification-aerobic denitrification strain which has aerobic denitrification and heterotrophic nitrification ability was selected, and then was identified as rhodococcus sp. by 16S rRNA sequencing anal...

The hydrometallurgical treatment of waste printed circuit boards for the recovery precious metals generates acidic wastewater containing nitrate, chloride and residual base metals. scope this work is study a biological process concurrent metal sequestering, nitrate reduction neutralization. A pilot-scale packed-bed biofilm reactor was set up, inoculated with strain H. denitrificans experimental...

The genome sequence of Rhizobium sullae strain HCNT1, isolated from root nodules of the legume Hedysarum coronarium growing in wild stands in Tuscany, Italy, is described here. Unlike other R. sullae strains, this isolate features a truncated denitrification pathway lacking NO/N2O reductase activity and displaying high sensitivity to nitrite under anaerobic conditions.