Thiobacillus ferrooxidans is found in many Alaskan and Canadian drainages contaminated by metals dissolved from placer and lode gold mines. We have examined the iron-limited growth and iron oxidation kinetics of a T. ferrooxidans isolate, AK1, by using batch and continuous cultures. Strain AK1 is an arsenic-tolerant isolate obtained from placer gold mine drainage containing large amounts of dis...

In this study, the effects of some factors on bacterial growth and ferrous oxidation rates were investigated by Acidithiobacillus ferrooxidan in 250 ml shake flasks. One factor at a time (OFAT) design approach was used for preliminary evaluation of various factors affecting the process, such as pH, initial ferrous and elemental sulfur concentrations, shaker agitation rate, and liquid to flask v...

Interactions between iron and sulfide in domestic wastewater from a gravity sewer were investigated with particular emphasis on redox cycling of iron and iron sulfide formation. The concentration ranges of iron and total sulfide in the experiments were 0.4-5.4mgFeL(-1) and 0-5.1mgSL(-1), respectively. During anaerobic conditions, iron reduction kinetics were investigated and reduction rates amo...

Anoxic iron-rich sediment samples that had been stored in the light showed development of brown, rusty patches. Subcultures in defined mineral media with ferrous iron (10 mmol/liter, mostly precipitated as FeCO3) yielded enrichments of anoxygenic phototrophic bacteria which used ferrous iron as the sole electron donor for photosynthesis. Two different types of purple bacteria, represented by st...

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 ...

Photoreduction of ferric to ferrous iron was determined in water held in bottles placed in a New Jersey Pinelands stream, although concentrations of ferrous iron in the stream itself remained below detection (15 ng mlI). The low ambient levels of ferrous iron apparently resulted from the action of iron-oxidizing microorganisms in water and soil, as shown by a temperature optimum for, and by the...

The biodegradation of iron-citrate complexes depends on the structure of the complex formed between the metal and citric acid. Ferric iron formed a bidentate complex with citric acid, [Fe(III) (OH)(2) cit] involving two carboxylic acid groups, and was degraded at the rate of 86 muM h. In contrast, ferrous iron formed a tridentate complex with citric acid, [Fe(II) cit], involving two carboxylic ...

The regulation of the expression of the rus operon, proposed to encode an electron transfer chain from the outer to the inner membrane in the obligate acidophilic chemolithoautroph Acidithiobacillus ferrooxidans, has been studied at the RNA and protein levels. As observed by Northern hybridization, real-time PCR and reverse transcription analyses, this operon was more highly expressed in ferrou...

Lakes developing in former coal mine pits are often characterized by high concentrations of sulfate and iron and low pH. The review focuses on the causes for and fate of acidity in these lakes and their watersheds. Acidification is primarily caused by the generation of ferrous iron bearing and mineralized groundwater, transport through the groundwater-surface water interface, and subsequent iro...

The chemical attack of ore by ferric iron and/or sulfuric acid releases valuable metals. The products of these reactions are recycled by iron and sulfur oxidizing microorganisms. These acidophilic chemolithotrophic prokaryotes, among which Acidithiobacillus ferrooxidans, grow at the expense of the energy released from the oxidation of ferrous iron and/or inorganic sulfur compounds (ISCs). In At...