Penicillium simplicissimum has previously been shown to solubilize pre-oxidized alkali-extracted sub-bituminous coal. The product of solubilization, a soluble acid-precipitable coal polymer, was isolated and characterized. The effects of oxidation pretreatments on the ability to solubilize coal were also examined. The intermediate product, which comprised 30% of the original coal, was readily recovered from the growth medium by acid precipitation and possibly consisted of a heterogeneous mixture of high-molecular-weight compounds of approximately 2·7 × 104 molecular weight. Further characterization by elemental analyses revealed that the bioproduct was enriched in inorganic materials, oxygen, nitrogen but lower in carbon, hydrogen and sulphur when compared with the original coal. A 14% loss of carbon atoms occurred during the biodegradation. The product had a featureless visible light spectrum and a shoulder in the ultraviolet range at 290 nm. Infrared analyses showed a decrease in aromatic carbons, methylenic bonds and etheric oxygen. Experimental results suggested that solubilization changes appear to be largely oxidative and may involve cleavage of intermonomeric linkages in coal.
Journal of Chemical Technology & Biotechnology 12/1994; 61(4):325 – 330. DOI:10.1002/jctb.280610407