Biodepyritization of indigenous coal using acidophilic, mesophilic and moderately thermophilic bacteria

This study was carried out for the identification of culturable bacteria present in the indigenous coal and to observe their depyritization capabilities in pure as well as in mixed consortia. Five mesophilic acidophilic isolates (B3, T1, T3, 1S and 1D), one moderately thermophilic (T2) iron and sulphur oxidizing isolate, two moderately thermophilic sulphur oxidizing isolates (NA-AT1, NA-AT2) and two acidophilic heterotrophic isolates (PK and PY) were purified from the coal samples and were identified on the basis of classical morphological and physiological basis. Coal biodepyritization studies were conducted using pure and mixed consortia of the isolated bacteria. Isolates B3 and T2 exhibited high coal biodepyritization rates as compared to all other isolates. Even higher biodepyritization rates were observed when mixed consortia of B3 and T2 were used with acidophilic heterotrophs (PY) and moderately thermophilic sulphur oxidizing bacteria (NA-AT1).