Denitrifïcation in Flexibacter canadensis

1990 ◽  
Vol 36 (6) ◽  
pp. 430-434 ◽  
Author(s):  
Alison M. Jones ◽  
Roger Knowles
Keyword(s):  
Nitrous Oxide ◽  
Sodium Sulfide ◽  
Electron Acceptors ◽  
Inhibition Assay ◽  
Oxide Reduction ◽  
Acetylene Inhibition ◽  
Gram Negative ◽  
Nitrous Oxide Reduction ◽  
Pure Cultures ◽  
Gliding Bacterium

Denitrifïcation was studied in pure cultures of Flexibacter canadensis (ATCC 29591), a Gram-negative gliding bacterium found in soil. Flexibacter canadensis was capable of using nitrate, nitrite, and nitrous oxide as terminal electron acceptors for growth. Sodium sulfide (200 μM) inhibited all of the nitrogen oxide reductases, but only temporarily. Acetylene (4 kPa) inhibited nitrous oxide reduction but did not affect the reduction of either nitrate or nitrite. However, sulfide (100 and 200 μM) alleviated the acetylene block and permitted reduction of nitrous oxide in the presence of 4 kPa acetylene. These data may have important implications regarding the use of the acetylene inhibition assay for measuring denitrifïcation rates in highly anaerobic, sulfidic environments. Key words: Flexibacter canadensis, denitrification, N2O reductase, sulfide, acetylene.

Sulfide alleviation of acetylene inhibition of nitrous oxide reduction by Flexibacter Canadensis

1992 ◽  
Vol 38 (2) ◽  
pp. 143-148 ◽  
Author(s):  
Alison M. Jones ◽  
Roger Knowles
Keyword(s):  
Nitrous Oxide ◽  
Pseudomonas Stutzeri ◽  
Sulfide Concentration ◽  
Oxide Reduction ◽  
Acetylene Inhibition ◽  
Experimental Conditions ◽  
Nitrous Oxide Reduction ◽  
Pure Cultures ◽  
Dissolved Sulfide ◽  
Key Words Denitrification

The role of sulfide in the relief of acetylene inhibition of nitrous oxide reduction by Flexibacter canadensis was studied. In this organism, the reversal of acetylene inhibition of nitrous oxide reduction is correlated with a 90% decrease in the dissolved sulfide concentration. The fate of this sulfide is not known, since there was no concomitant increase in acid-soluble sulfide and volatile sulfur compounds were not detectable by flame photometric gas chromatography. Of the other sulfur-containing compounds tested (sulfate, sulfite, thiosulfate, cysteine, methionine, dithionite, dithionate, and glutathione), only cysteine relieved the acetylene block of nitrous oxide reduction by F. canadensis. Under similar experimental conditions, other denitrifiers tested (Azospirillum brasilense, Pseudomonas stutzeri, and a Flavobacterium isolate) failed to reduce nitrous oxide in the presence of sulfide and an inhibitory concentration of acetylene. It is concluded that both biological and abiological factors contribute to the sulfide relief of acetylene inhibition of nitrous oxide by pure cultures of F. canadensis. Key words: denitrification, nitrous oxide, acetylene, sulfide, Flexibacter canadensis.

Identification of a denitrifying gliding bacterium, isolated from soil and able to reduce nitrous oxide in the presence of sulfide and acetylene, as Flexibacter canadensis

1990 ◽  
Vol 36 (11) ◽  
pp. 765-770 ◽  
Author(s):  
Alison M. Jones ◽  
Anne M. Adkins ◽  
Roger Knowles ◽  
Gina R. Rayat
Keyword(s):  
Nitrous Oxide ◽  
Key Words ◽  
Dna Hybridization ◽  
Inhibition Assay ◽  
Acetylene Inhibition ◽  
Biochemical Tests ◽  
Gliding Bacteria ◽  
Soil Isolate ◽  
Gliding Bacterium ◽  
Physiological And Biochemical

We have reexamined the properties of a gliding bacterium, Is-11, which was previously isolated from soil because of its ability to denitrify and to reduce nitrous oxide in the presence of sulfide and normally inhibitory concentrations of acetylene. Occurrence of such an organism may have important implications for the use of the acetylene inhibition assay for measuring denitrification rates in reduced, sulfidic environments. Although originally tentatively identified as a Cytophaga sp., extensive morphological, physiological, and biochemical tests as well as G+C analysis and DNA hybridization studies now indicate that the soil isolate Is-11 is a strain of Flexibacter canadensis. Key words: gliding bacteria, Flexibacter canadensis, denitrification, acetylene, sulfide, nitrous oxide.

Effects of sulfide and acetylene on nitrous oxide reduction by soil and by Pseudomonas aeruginosa

1979 ◽  
Vol 25 (10) ◽  
pp. 1133-1138 ◽  
Author(s):  
Tat-Yee Tam ◽  
Roger Knowles
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Nitrous Oxide ◽  
Sodium Sulfide ◽  
Sodium Thiosulfate ◽  
Cell Suspensions ◽  
Inhibition Assay ◽  
Sterile Soil ◽  
Washed Cell ◽  
Complete Reduction ◽  
Nitrous Oxide Reduction

The production and reduction of nitrous oxide (N2O) after the addition of N2O, nitrite (NO2−), or nitrate (NO3−) was studied in non-sterile soil, in sterilized soil inoculated with Pseudomonas aeruginosa, and in washed cell suspensions of this organism. Sodium sulfide (8 μmol S2− mL−1 or g−1) inhibited N2O reduction markedly in cell suspensions and also in soil, an effect which may cause sulfidic habitats to act as sources of N2O. Sodium thiosulfate (up to 64 μmol S2O32− g−1) showed no such effect. Acetylene (0.02 atm C2H2) completely inhibited the reduction of N2O by soil, but the combination of C2H2 with 8 μmol S2− g−1 permitted the complete reduction of 2 μmol added N2O g−1 within 3 days under the most favourable conditions. Under the same conditions, 8 μmol S2O32− g−1 permitted complete reduction of the N2O within 6 days. The rate of such reduction of N2O was decreased, but not inhibited completely, by raising the C2H2 concentration to 0.11 atm. The data have important implications for the effectiveness of the C2H2 inhibition assay of denitrification in highly anaerobic environments.

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