Coal sulphur transformations monitored by hyperthermophilic archaebacteria

The hyperthermophilic archaebacterium Pyrococcus furiosus can reduce polysulphidic compounds as well as elemental sulphur bound in coal. The presence of elemental sulphur in coals is thought to be a result of low temperature oxidation, or weathering, of coal pyrite. Results of controlled coal weathering experiments, in which the transformation of sulphur moieties was monitored using P. furiosus as well as standard chemical analyses, suggest that there may be changes in the organic sulphur content of coal during treatment. Observed transformations make coal sulphur more amenable to reduction by P. furiosus and, perhaps, other sulphur-reducing bacteria. Along these lines, the potential basis for combined biological and chemical treatment of coal to remove organic sulphur should be given serious consideration in developing coal cleaning technology.