Oxidation von Nitrit durch anoxygene phototrophe Bakterien
Zusammenfassung der Projektergebnisse
The physiology of phototrophic nitrite oxidation was studied with a pure culture of Thiocapsa sp. strain KS1. A further strain of phototrophic nitrite oxidizer was isolated from enrichment cultures and was assigned to the genus Rhodopseudomonas on the basis of 16S rRNA gene sequence similarity. Since the latter isolate grew very slowly and only to low yields with nitrite, most of our studies concentrated on the Thiocapsa strain which, based on 16S rRNA gene sequence similarity, appeared to be most closely related to T. roseopersicina, T. rosea, and T. marina. With both strains, nitrite oxidation depended strongly on the availability of light. Both strains exhibited light absorption spectra typical of Thiocapsa sp. or Rhodopseudomonas sp.-like bacteria, respectively. Beyond nitrite, Thiocapsa sp. strain KS1 utilized thiosulfate, sulphide, and few organic compounds for growth; Rhodopseudomonas strain LQ17 could also use thiosulfate to a low extent, but preferred organic substrates. The nitrite-oxidizing enzyme activity of Thiocapsa sp. strain KS1 was specifically expressed after growth with nitrite; no activity was found after growth with hydrogen of fructose. In SDS-PAGE analysis, nitrite-grown cells of Thiocapsa sp. exhibited specific bands at molecular masses of 65 and 115 kDa, resembling those of the nitrite-oxidizing enzyme of Nitrobacter hamburgensis.
Projektbezogene Publikationen (Auswahl)
- Nitrite, an electron donor for anoxygenic photosynthesis. Science 316, 1870. (2007)
Griffin, B., J. Schott, B. Schink
- Anaerobic phototrophic nitrite oxidation by Thiocapsa sp. strain KS1 and Rhodopseudomonas sp. strain LQ17. Microbiology (UK) 156, 2428-2437 (2010)
Schott, J., B. M. Griffin, B. Schink
