Optimization of Phenol Removal from Biorefinery Effluent Using Horseradish Peroxidase

Abstract

Biorefinery is a facility comprising industrial processes for the production of fuel and chemicals from biomass. Because there is a growing number of biorefineries worldwide, the related environmental aspects have to be studied. Following this context, this paper examines the application of horseradish peroxidase (HRP) for the treatment of high-phenol-content wastewaters from a biorefinery. The enzyme was characterized, and its optimal conditions for phenol removal were evaluated by an experimental design 25−1 central composite rotatable design. The results showed a bioconversion yield above 99% using pH 6.32, enzyme concentration of 56.68 U, temperature of 28°C, 1.24 g/L of hydrogen peroxide, and 35-min reaction time. The chromatographic analysis showed that, among total phenols, the 2-methoxyphenol was the majority compound, while many other phenolic compounds were present at trace levels. Furthermore, other physicochemical parameters were reduced after the enzymatic treatment, such as biochemical oxygen demand (98.13%) and chemical oxygen demand (49.39%). Enzymatic phenol removal using HRP can be a valuable strategy for biorefinery wastewater treatment.