Coal metabolizing Pseudomonas cepacia DLC-07 was isolated from soil and shown to use soluble lignite coal as a carbon/energy source. Pseudomonas modified coal residues were characterized by FT-IR, HPLC, elemental analysis, and13C-NMR. P. cepacia DLC-07 depolymerized lignite, as shown by HPLC. FT-IR analysis showed fewer carbonyl and carboxyl groups, decreased etheric oxygen, and fewer aromatic and conjugated carbon-carbon double bonds in modified, compared to control coal.13C-NMR indicated a decrease in carbonyls and heteroaromatic carbons containing N, O, and S, a decrease in unsubstituted aromatic carbons, and an increase in long chain methylenes in treated coal. Elemental analysis supported the spectral data concerning metabolism of the coal polymer. P. cepacia cometabolized coal model compounds and utilized p-hydroxy substituted benzoic or cinnamic acids or aldehydes as sole carbon and energy sources. © 1990 Humana Press Inc.