Enzyme Catalyzed Polymerization and Precipitation of Aromatic Compounds from Wastewater

Abstract

Horseradish peroxidase enzyme (HRP) catalyzes the oxidation of aromatic compounds by hydrogen peroxide. Reaction products undergo a non-enzymatic polymerization to form water insoluble aggregates which readily separate from solution. The capabilities of HRP in catalyzing the precipitation of phenols from synthetic wastewaters in batch and mixed-flow reactors are being explored. Clearance tests have shown that HRP is effective in polymerizing phenolic substrates in water. The effects of varying aromatic, enzyme and peroxide concentrations are investigated. Aromatics and peroxide react with a one-to-one stoichiometry. The catalytic lifetime of HRP improves when the reaction is conducted at the optimum pH, below 35°C, and at low enzyme concentration. The choice of a reactor configuration for a continuous-flow process is based on the results of the batch and semi-batch reactor studies. Treatment of wastewater in a continuous stirred tank reactor improves catalyst efficiency.