Microorganisms able to utilize untreated Morwell lignite and the fraction insoluble in tetrahydrofuran (THF) as their sole carbon and energy source were isolated by enrichment from coal exposures in Victoria. Most isolates can use a variety of long-chain aliphatic and single-ring aromatic compounds but not more complex aromatic substrates, indicating that their growth on whole lignite is due to use of the low-molecular-weight compounds constituting the mobile phase and bound aliphatic moieties which can be cleaved from the macromolecular coal matrix. Organisms able to utilize THF-insoluble lignite are less abundant than those able to use whole coal. Amongst these are isolates able to utilize diaryl compounds and anthraquinones, compounds with structures analogous to components of the macromolecular matrix of lignite. Two fungal isolates, CJ2 and CJ4, were found to alter the elution profile of alkali-solubilized Morwell lignite in size-exclusion chromatography. When incubated with these fungi in growth medium, the apparent molecular weight of the lignite increased by 10000. However, when polyvalent metal ions were removed, the apparent molecular weight was lower than that of uninoculated coal, indicating attack on the macromolecular matrix of the lignite.
- coal conversion