Improving the synthesis of phenolic polymer using Coprinus cinereus peroxidase mutant Phe230Ala

•The radical-stable mutant of CiP (F230A) was applied to the phenol polymerization.•The F230A mutant produced a 5.6 fold-higher molecular weight of phenol polymer.•The organic solvents affected the polymerization yield of CiP proteins.•The F230A mutant exhibited lower stability in organic solvents than the wild-type.•The wild-type and F230A mutant showed comparable kinetic parameters. The F230A mutant of Coprinus cinereus peroxidase (CiP), which has a high stability against radical-inactivation, was previously reported. In the present study, the radical-robust F230A mutant was applied to the oxidative polymerization of phenol. The F230A mutant exhibited better polymerization activities than the wild-type CiP in the presence of water-miscible alcohols i.e., methanol, ethanol, and isopropanol despite its lower stability against alcohols. In particular, the F230A mutant showed a higher consumption of phenol (40%) and yielded phenolic polymer of larger molecular weight (8850Da) in a 50% (v/v) isopropanol-buffer mixture compared with the wild-type CiP (2% and 1519Da, respectively). In addition, the wild-type CiP and F230A mutant had no significant differences in enzyme inactivation by physical adsorption on the polymeric products or by heat incubation, and showed comparable kinetic parameters. These results indicate that high radical stability of the F230A mutant and improved solubility of phenolic polymers in alcohol-water cosolvent systems may synergistically contribute to the production of the high molecular weight phenolic polymer.