Acidithiobacillus ferrooxidans is a Gram-negative bacterium that obtains energy by oxidizing Fe(2+) or reduced sulfur compounds. This bacterium contributes to the formation of acid mine drainage (AMD). This study determined whether walnut shell powder inhibits the growth of A. ferrooxidans. First, the effects of walnut shell powder on Fe(2+) oxidization and H⁺ production were evaluated. Second,...

The composition of bacterial populations in copper bioleaching systems was investigated by analysis of DNA obtained either directly from ores or leaching solutions or after laboratory cultures. This analysis consisted of the characterization of the spacer regions between the 16 and 23S genes in the bacterial rRNA genetic loci after PCR amplification. The sizes of the spacer regions, amplified f...

Glutamyl-tRNA synthetases (GluRSs) occur in two types, the discriminating and the nondiscriminating enzymes. They differ in their choice of substrates and use either tRNAGlu or both tRNAGlu and tRNAGln. Although most organisms encode only one GluRS, a number of bacteria encode two different GluRS proteins; yet, the tRNA specificity of these enzymes and the reason for such gene duplications are ...

Of 100 strains of iron-oxidizing bacteria isolated, Thiobacillus ferrooxidans SUG 2-2 was the most resistant to mercury toxicity and could grow in an Fe(2+) medium (pH 2.5) supplemented with 6 microM Hg(2+). In contrast, T. ferrooxidans AP19-3, a mercury-sensitive T. ferrooxidans strain, could not grow with 0.7 microM Hg(2+). When incubated for 3 h in a salt solution (pH 2.5) with 0.7 microM Hg...

Acidithiobacillus ferrooxidans is a gram-negative chemolithoautotrophic γ-proteobacterium. It typically grows at an external pH of 2 using the oxidation of ferrous ions by oxygen, producing ferric ions and water, while fixing carbon dioxide from the environment. A. ferrooxidans is of great interest for biomining and environmental applications, as it can process mineral ores and alleviate the ne...

A 1.3-kb insertion sequence, termed ISAfe1 (U66426), from Acidithiobacillus ferrooxidans ATCC 19859 is described. ISAfe1 exhibits the features of a typical bacterial insertion sequence. It has 26-bp, imperfectly matched, terminal inverted repeats and an open reading frame (ORF) that potentially encodes a transposase (TPase) of 404 amino acids (AAB07489) with significant similarity to members of...

The presence of two sets (rbcL1-rbcS1 and rbcL2-rbcS2) of rbc operons has been demonstrated in Thiobacillus ferrooxidans Fe1 (T. Kusano, T. Takeshima, C. Inoue, and K. Sugawara, J. Bacteriol. 173:7313-7323, 1991). A possible regulatory gene, rbcR, 930 bp long and possibly translated into a 309-amino-acid protein, was found upstream from the rbcL1 gene as a single copy. The gene is located diver...

The ex-situ bioremoval of U(VI) from contaminated water using Acidithiobacillus ferrooxidans strain 8455 and 13538 was studied under a range of pH and uranium concentrations. The effect of pH on the growth of bacteria was evaluated across the range 1.5–4.5 pH units. The respiration rate of At. ferrooxidans at different U(VI) concentrations was quantified as a measure of the rate of metabolic ac...

A variety of acidophilic microorganisms were shown to be capable of oxidizing formate. These included Thiobacillus ferrooxidans ATCC 21834, which, however, could not grow on formate in normal batch cultures. However, the organism could be grown on formate when the substrate supply was growth limiting, e.g., in formate-limited chemostat cultures. The cell densities achieved by the use of the lat...

Molecular studies of enzymes involved in sulfite oxidation in Acidithiobacillus ferrooxidans have not yet been developed, especially in the ATP sulfurylase (ATPS) of these acidophilus tiobacilli that have importance in biomining. This enzyme synthesizes ATP and sulfate from adenosine phosphosulfate (APS) and pyrophosphate (PPi), final stage of the sulfite oxidation by these organisms in order t...