Several different strains of fungi have been shown to solubilize some types of low-ranked coal, apparently by an extracellular process. Oxidative pretreatment enhances the microbial action, allowing the use of a variety of coal feedstocks. The resulting product, which is primarily a mixture of polar organic compounds with moderate to high molecular weights and a high degree of aromaticity, is water-soluble. Possible processing concepts include the use of continuous bioreactors configured as either fixed or fluidized beds.

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Paecilomyces sp. TLi, a coal-solubilizing fungus, was shown to degrade organic sulfur-containing coal substructure compounds. Dibenzothiophene was degraded via a sulfur-oxidizing pathway to 2,2'-dihydroxybiphenyl. No further metabolism of that compound was observed. Ethyl phenyl sulfide and diphenyl sulfide were degraded to the corresponding sulfones. A variety of products were formed from dibenzyl sulfide, presumably via free radical intermediates. Diphenyl disulfide and dibenzyl disulfide were cleaved to the corresponding thiols and other single-ring products. It was concluded that degradation of organic sulfur compounds by Paecilomyces involves an oxidative attack localized at the sulfur atom.

Resting cells of Micrococcus luteus have been shown to remove strontium (Sr) from dilute aqueous solutions of SrCl2 at pH 7. Loadings of 25 mg of Sr per g of cell dry weight were achieved by cells exposed to a solution containing 50 ppm (mg/liter) of Sr. Sr binding occurred in the absence of nutrients and did not require metabolic activity. Initial binding was quite rapid (<0.5 h), although a slow, spontaneous release of Sr was observed over time. Sr binding was inhibited in the presence of polyvalent cations but not monovalent cations. Ca and Sr were bound preferentially over all other cations tested. Sr-binding activity was localized on the cell envelope and was sensitive to various chemical and physical pretreatments. Bound Sr was displaced by divalent ions or by H+. Other monovalent ions were less effective. Bound Sr was also removed by various chelating agents. It was concluded that Sr binding by M. luteus is a reversible equilibrium process. Both ion exchange mediated by acidic cell surface components and intracellular uptake may be involved in this activity.