Abstract
Degradation of styrene monomer and polystyrene by a white-rot fungus Phanerochaete chrysosporium was examined. As degradation products of styrene monomer, 4-hydorxy benzoic acid and mandelic acid were detected, which were not determined in styrene-metabolizing bacteria. However, degradation of polystyrene was not determined with any chemical changes. Reactivity of styrene monomer and polystyrene was simulated with a semi-empirical molecular orbital calculation program MOPAC. One pathway of styrene degradation is estimated as the initial hydroxylation at 4-position of styrene and the following oxidation to form 4-hydroxy benzoic acid. Another is predicted as the oxidation of the vinyl group to form mandelic acid. As a result of the HOMO calculation of styrene oligomers, the energy level was slightly lower than that of styrene monomer at 4-position of aromatic ring. Therefore, the low biodegradability of polystyrene is estimated to be due to its high hydrophobicity.
