Polymerization of guaiacol by lignin-degrading manganese peroxidase from Bjerkandera adusta in aqueous organic solvents

Lignin-degrading manganese (II) peroxidase (MnP) purified from the culture of a wood-rotting basidiomycete, Bjerkandera adusta, was used in the polyme rization of guaiacol. MnP was found to catalyze polymerization of guaiacol in 50% aqueous acetone, dimethyl formamide, methanol, ethanol, dioxane, ace tonitrile, ethylene glycol and methylcellosolve. Maximum yield of polyguaia col was achieved in 50% aqueous acetone. The weight average molecular weigh t (M-w) of the polymer was estimated to be 30 304 by gel permeation chromat ography. However, matrix-assisted laser desorption ionization time of fligh t mass spectroscopy (MALDI-TOF-MS) analysis gave a more reliable M-w of 169 0. IR, C-13-NMR, MALDI-TOF-MS and pyrolysis GC-MS analyses showed the prese nce of C-C and C-O linkages and quinone structure in polyguaiacol. It was a lso indicated that polyguaiacol has a methoxy-phenyl group as the terminal moiety. This suggests that polyguaiacol is a branched polymer in which guai acol units are cross-linked at the phenolic group. Thermal gravimetric and differential scanning calorimetric analyses were also carried out. MnP also catalyzed the polymerization of o-cresol, 2,6-dimeth-oxyphenol and other p henolic compounds and aromatic amines. M-w of these polymers ranged from ar ound 1000 to 1500.