Thiobacillus ferrooxidans was used in fixed-film bioreactors to oxidize ferrous sulfate to ferric sulfate. Glass beads, ion-exchange resin, and activated-carbon particles were tested as support matrix materials. Activated carbon was tested in both a packed-bed bioreactor and a fluidized-bed bioreactor; the other matrix materials were used in packed-bed reactors. Activated carbon displayed the m...

The oxidation of either ferrous iron or sulfur by Thiobacillus ferrooxidans was selectively inhibited or controlled by various anions, inhibitors, and osmotic pressure. Iron oxidation was more sensitive than sulfur oxidation to inhibition by chloride, phosphate, and nitrate at low concentrations (below 0.1 M) and also to inhibition by azide and cyanide. Sulfur oxidation was more sensitive than ...

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 with 1 mol of elemental sulfur to give 6 mol of Fe, 1 mol of sulfate, and a small amount of sulfite. In aerobic conditions, the 6 mol of Fe...

Fifty mesophilic and five moderately thermophilic strains of acidophilic heterotrophic bacteria were tested for the ability to reduce ferric iron in liquid and solid media under aerobic conditions; about 40% of the mesophiles (but none of the moderate thermophiles) displayed at least some capacity to reduce iron. Both rates and extents of ferric iron reduction were highly strain dependent. No a...

A method for direct, continuous determination of ferric ions produced in autotrophic iron oxidation, which depends upon the measurement of ferric ion absorbance at 304 nm, is described. The use of initial rates is shown to compensate for such changes in extinction during oxidation, which are due to dependence of the extinction coefficient on the ratio of complexing anions to ferric ions. A grap...

Ferrous sulphate, a waste product in titanium white production at the Chemical Plant "Police" S.A., was subjected to microbiological oxidation with Thiobacillus ferrooxidans bacteria. The kinetic parameters of the culture growth were calculated on the basis of the Monod equation. The process was found to be best described by the model of the autocatalytic 1st order reaction with respect to the ...

The increased rate of solubilization of sulfide ores of iron and copper caused by Thiobacillus ferrooxidans has been attributed either to direct action of the bacteria on the ore or to an indirect effect whereby the ferric ion is presumed to oxidize the ore and is returned to the active, oxidized state by the iron-oxidizing bacteria. Attempts by M. P. Silverman (3) to demonstrate that microbial...

Coal mine drainage refers to the acidic drainage caused by surface mining, deep mining or coal refuse piles. Being highly acidic with elevated levels of dissolved metals, it is otherwise known as “Acid Mine Drainage (AMD)”. Formation of AMD is due to a series of geochemical and microbiological processes involving acidophilic chemolithotrophs such as Thiobacillus, Thiomispora, Leptospirillum etc...