Soybean peroxidase-catalyzed removal of an aromatic thiol, 2-mercaptobenzothiazole, from water.

This paper demonstrates, for the first time, the capability of soybean peroxidase (SBP), an enzyme, for catalyzing the removal of an aromatic thiol, 2-mercaptobenzothiazole (MBT), from aqueous solution. The optimum pH for enzymatic conversion of MBT in aqueous buffer was found to be in the range 6.0 to 9.0. The optimum hydrogen peroxide (H2O2): MBT stoichiometry was 0.6. In terms of standard units (U) of catalytic activity, the minimum SBP concentration required for 95% conversion of 1.0 mM MBT in 3 hours was found to be 0.9 U/mL. The presence of polyethylene glycol at 50 mg/L can reduce the enzyme concentration required for the same conversion by 3-fold. It is proposed that these findings should be the basis for viable and cost-effective treatment of MBT in industrial wastewater and/or process water.