Role of a ferric ion-reducing system in sulfur oxidation of Thiobacillus ferrooxidans
The properties of a ferric ion-reducing system which catalyzes the reduction of ferric ion with elemental sulfur was investigated with a pure strain of Thiobacillus ferrooxidans. In anaerobic conditions, washed intact cells of the strain reduced 6 mol of Fe/sup 3 +/ with 1 mol of elemental sulfur to give 6 mol of Fe/sup 2 +/, 1 mol of sulfate, and a small amount of sulfite. In aerobic conditions, the 6 mol Fe/sup 2 +/ produced was immediately reoxidized by the iron oxidase of the cell, with a consumption of 1.5 mol of oxygen. As a result, Fe/sup 2 +/ production was never observed under aerobic conditions. However, in the presence of 5 mM cyanide, which completely inhibits the iron oxidase of the cell, an amount of Fe/sup 2 +/ production comparable to that formed under anaerobic conditions was observed under aerobic conditions. The ferric ion-reducing system had a pH optimum between 2.0 and 3.8, and the activity was completely destroyed by 10 min of incubation at 60/sup 0/C. A short treatment of the strain with 0.5% phenol completely destroyed the ferric ion-reducing system of the cell. However, this treatment did not affect the iron oxidase of the cell. Since a concomitant complete loss of the activity of sulfur oxidation by molecular oxygen was observed in 0.5% phenol-treated cells, it was concluded that the ferric ion-reducing system plays an important role in the sulfur oxidation activity of this strain, and a new sulfur-oxidizing route is proposed for T. ferrooxidans.
- Research Organization:
- Okayama Univ., Japan
- OSTI ID:
- 6035532
- Journal Information:
- Appl. Environ. Microbiol.; (United States), Journal Name: Appl. Environ. Microbiol.; (United States) Vol. 49:6; ISSN AEMID
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
560302 -- Chemicals Metabolism & Toxicology-- Microorganisms-- (-1987)
59 BASIC BIOLOGICAL SCIENCES
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANAEROBIC CONDITIONS
AROMATICS
BACILLUS
BACTERIA
BIOCONVERSION
BIOLOGICAL PATHWAYS
CATIONS
CHARGED PARTICLES
CHEMICAL REACTIONS
ELEMENTS
ENZYMES
HYDROXY COMPOUNDS
IONS
IRON COMPOUNDS
METABOLISM
MICROORGANISMS
NONMETALS
ORGANIC COMPOUNDS
OXIDATION
OXIDOREDUCTASES
PHENOL
PHENOLS
SULFUR
SULFUR-OXIDIZING BACTERIA
TEMPERATURE DEPENDENCE
THIOBACILLUS FERROXIDANS
TOXICITY
TRANSITION ELEMENT COMPOUNDS