Rapid and specific detection of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans by PCR

Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans are two of the most important bacteria in heap bioleaching processes of copper sulphide at common operating temperatures (18–24 °C). In this paper, both microorganisms were detected in solutions and ores coming from processes in 2 days, using specific amplification of 16S rDNA sequences by PCR. The technique was first validated using template DNA from pure cultures of the microorganisms. Then it was applied to samples of solutions and ores from bioleaching processes. Results were confirmed using tRFLP (terminal Restriction Fragment Length Polymorphism) with universal primers and by identification of isolated bacteria by means of culture. This methodology is more rapid and specific than the identification by tRFLP or by culture, which require from 1 to three weeks to positively detect the bacteria. The detection limit of this technique is 10⁵ cells per ml.