Influence of Volatile Fatty Acids on Nitrite Accumulation by a Pseudomonas stutzeri Strain Isolated from a Denitrifying Fluidized Bed Reactor

Abstract

Intermediate nitrite accumulation during denitrification by Pseudomonas stutzeri isolated from a denitrifying fluidized bed reactor was examined in the presence of different volatile fatty acids. Nitrite accumulated when acetate or propionate served as the carbon and electron source but did not accumulate in the presence of butyrate, valerate, or caproate. Nitrite accumulation in the presence of acetate was caused by differences in the rates of nitrate and nitrite reduction and, in addition, by competition between nitrate and nitrite reduction pathways for electrons. Incubation of the cells with butyrate resulted in a slower nitrate reduction rate and a faster nitrite reduction rate than incubation with acetate. Whereas nitrate inhibited the nitrite reduction rate in the presence of acetate, no such inhibition was found in butyrate-supplemented cells. Cytochromes b and c were found to mediate electron transport during nitrate reduction by the cells. Cytochrome c was reduced via a different pathway when nitrite-reducing cells were incubated with acetate than when they were incubated with butyrate. Furthermore, addition of antimycin A to nitrite-reducing cells resulted in partial inhibition of electron transport to cytochrome c in acetate-supplemented cells but not in butyrate-supplemented cells. On the basis of these findings, we propose that differences in intermediate nitrite accumulation are caused by differences in electron flow to nitrate and nitrite reductases during oxidation of either acetate or butyrate.

Effects of cultural conditions on denitrification by Pseudomonas stutzeri measured by Membrane Inlet Mass Spectrometry

“…Different volatile fatty acids used as carbon sources have also been shown to influence nitrite accumulation in Ps. stutzeri (van Rijn et al 1996), and pH influences the process in Paracoccus denitrificans (Kučera 1986). Körner and Zumft (1989) found that nitrate inhibition of nitrite reductase could lead to a nitrite build up in Ps.…”

“…stutzeri, a known denitrifier, which is widely disseminated in many environments (e.g. van Rijn et al 1996). It possesses the full complement of denitrifying enzymes and is therefore capable of producing inert nitrogen as the end product.…”

Characterisation of dominant autochthonous strains for nitrite degradation of Chinese traditional fermented fish

“…In pH 5.0, 4.0, 3.5 and 3.0 groups, the final nitrite concentrations were 16.32, 12.99, 9.87 and 4.92 mg L À1 , respectively. Van Rijn et al (1996) reported a similar result that the nitrite could not accumulate in butyric acid, valeric acid and hexanoic acid. The degradation of nitrite in acid environment could be attributed to disproportionation reaction between NO À 2 and H + (Knipp et al, 2011), and the reaction equation was described as follows: Fig.…”

Nitrite reduction in Paracoccus sp. is affected by a novel plasmid pYR1

“…Paracoccus sp. was isolated from a £uidized-bed reactor used for nitrate removal in intensive ¢sh-culture systems [7]. In addition to heterotrophic denitri¢cation on a wide array of organic substrates, the strain exhibited autotrophic denitri¢cation in the presence of reduced sulfur compounds (unpublished results).…”

“…Its intermediate formation during the denitri¢cation process is in£uenced by a number of factors. Among those: (i) elevated oxygen levels [3,4], (ii) shifts in pH values [5], (iii) nitrate concentrations [6,7], (iv) nitrate starvation [8], (v) light exposure [9], and (vi) the presence of phosphate [10].…”