Investigation of the microbial diversity of an extremely acidic, metal-rich water body (Lake Robule, Bor, Serbia)

Abstract

An investigation of the microbial diversity of the extremely acidic, metal-rich Lake Robule was carried out using culture-dependant and culture-independent (T-RFLP) methods, and the ability of indigenous bacteria from the lake water to leach copper from a mineral concentrate was tested. T-RFLP analysis revealed that the dominant bacteria in lake water samples were the obligate heterotroph Acidiphilium cryptum (~50% of total bacteria) and the iron-oxidizing autotroph Leptospirillum ferrooxidans (~40%) The iron/sulfur-oxidizing autotroph Acidithiobacillus ferrooxidans had been reported to be the most abundant bacteria in the lake in an earlier study by other authors, but it was not detected in the present study using T-RFLP. Although it was isolated on solid media and detected in enrichment (bioleaching) cultures. The presence of the two bacterial species detected by T-RFLP (L. ferrooxidans and A. cryptum) was also confirmed by cultivation on solid media. The presence and relative abundance of bacteria inhabiting Lake Robule was explained by the physiological characteristics of the bacteria and the physico-chemical characteristics of the lake water.