Odor Control in Waste Management Lagoons via Reduction of p-Cresol using Horseradish Peroxidase

Para-cresol, p-ethyl phenol and isovaleric acid have been identified as the most persistent and most significant contributors to odor 1.6 km downwind from waste lagoons in concentrated animal feeding operations (CAFOs), even though more than 200 volatile compounds contribute to odor from these lagoons. Previous studies have indicated that horseradish peroxidase (HRP) coupling with p-cresol generates a high yield of a unique product, Plummerer's ketone. Our preliminary laboratory studies with synthetic p-cresol, hydrogen peroxide, and HRP demonstrated that p-cresol can be reduced significantly in a hydrogen peroxide catalyzed reaction with HRP. Using GC/MS and SPME technologies, a 75% reduction was observed in relative concentrations of 100 ml 1% p-cresol after treatment with 1 ml of 170 units of HRP (prepared at 170 units/mg and 1 mg/ml) in the presence of 3% hydrogen peroxide. Further analyses using semi- volatile organic analyses- GC/MS shows a 41% reduction in the amount of p-cresol in the samples treated with HRP in the presence of hydrogen peroxide. Data obtained from these preliminary studies demonstrate that HRP has the potential to reduce the p-cresol content in CAFO effluent and has been a basis for further studies.