Growth ofThiobacillus ferrooxidans on solid media containing heterotrophic bacteria

A simple procedure for elimination of fungal contamination for enumeration of iron-oxidizing bacteria from bioleaching matrix of sewage sludge

“…The introduction of heterotrophic microorganisms onto the solid medium did not show further improvement in either plating efficiency or shortening of the incubation time required for the enumeration of iron-oxidizing bacteria for sludge samples (Table 2), as reported in literature (Butler and Kempton 1987;Johnson 1995). Similar results were also obtained for pure cultures of Acidithiobacillus ferrooxidans strans ATCC19859 (Table 3) and XL (data not shown).…”

“…The major difficulty encountered during the enumeration of chemolithotrophic iron-oxidizing bacteria is their reluctance to form colonies on solid medium. A dramatic increase in plating efficiencies has been reported, and the incubation time could be shortened from 30 to 12 d (Butler and Kempton 1987;Johnson 1995). To overcome such a difficulty, the membrane filtration technique has been proposed to separate the colony from the medium surface; but colony development depends on membrane and agar type, as well as the pH and age of the medium (Tuovinen and Kelly 1973;Escobar and Godoy 2000).…”

Acidophiles in Biomining

“…pyruvate) can inhibit the growth of T. ferrooxidans (Tuttle & Dugan, 1976) so their removal by acidophilic heterotrophs can benefit the autotroph. The efficient scavenging of organic material from their surroundings by the heterotrophs has been employed successfully in the development of solid media for isolating acidophilic autotrophs (Butler & Kempton, 1987;Johnson & McGinness, 1991). Incorporation of heterotrophs in an underlay of agarose-gelled medium promotes growth of the autotrophs.…”

Microbial Leaching of Metals

“…2). This group of organisms uses extracellular metabolites and cell lysates from autotrophs as carbon source resulting in the removal of an inhibitory excess of carbon and stimulating, therefore, growth and iron oxidation of thiobacilli (BUTLER and KEMPTON, 1987;FOURNIER et al, 1998). In addition, several heterotrophs can also contribute to metal solubilization by the excretion of organic acids such as citrate, gluconate, oxalate, or succinate.…”