Reduction of oxidized inorganic nitrogen compounds by a new strain of Thiobacillus denitrificans

Abstract

Denitrification by Thiobacillus denitrificans "RT" strain was investigated using manometry and gas chromatography. 1. From nitrate, resting cells produced only nitrogen anaerobically with thiosulfate as the electron donor. The data suggest that nitrate was assimilated and dissimilated by the same nitrate reductase, assayed with benzyl-viologen as the electron donor. 2. From nitrite, whole cells produced nitric oxide, nitrous oxide and nitrogen, using thiosulfate as the electron donor; nitrogen was the final product of the reduction. Crude extract reduced nitrite to nitrogen with p-phenylene-diamine and dimethyl-p-phenylene diamine as the electron donors, and produced nitric oxide, nitrous oxide and nitrogen with tetramethyl-p-phenylene-diamine as the electron donor. Nitrite was reduced to nitric oxide and nitrous oxide by crude extract using ascorbate-phenazine methosulfate as the electron donor. 3. From nitric oxide, whole cells produced nitrous oxide and nitrogen using thiosulfate as the electron donor, nitrogen was the final reduction product. Nitric oxide was reduced to nitrous oxide by crude extract with the ascorbate-phenazine methosulfate system. 4. Whole cells reduced nitrous oxide to nitrogen with thiosulfate as the electron donor. It was not possible to detect any nitrous oxide reductase activity in crude extract. 5. A scheme was of denitrification by Thiobacillus denitrificans "RT" strain.