The degradability of total petroleum hydrocarbons (TPH)‐contaminated soils by hemoglobin‐catalyzed oxidation with hydrogen peroxide (H2O2) was investigated using 8 g H2O2 kg−1 soil and 3.3 g hemoglobin kg−1 soil. When both hemoglobin and H2O2 were used to initiate the oxidation reaction, approximately 76% TPH removal was achieved, while only 26% was removed when only H2O2 was used. This shows that the TPH removal can be enhanced in the presence of hemoglobin as a catalyst. In addition, the toxic effect of the soil treated by the hemoglobin‐catalyzed oxidation, determined using Microtox®, was reduced by about three times compared to the untreated soil. Overall, this study shows that hemoglobin may successfully act as a catalyst enhancing TPH removal in soils.

Biocatalytic degradation of total petroleum hydrocarbons (TPHs) in contaminated soil by hemoglobin and hydrogen peroxide is an effective soil remediation method. This study used a laboratory soil reactor experiment to evaluate the effectiveness of a nonspecific biocatalytic reaction with hemoglobin and H 2 O 2 for treating TPH-contaminated soil. We also quantified changes in the soil microbial community using real-time PCR analysis during the experimental treatment. The results show that the measured rate constant for the reaction with added hemoglobin was 0.051/day, about 3.5 times higher than the constant for the reaction with only H 2 O 2 (0.014/day). After four weeks of treatment, 76% of the initial soil TPH concentration was removed with hemoglobin and hydrogen peroxide treatment. The removal of initial soil TPH concentration was 26% when only hydrogen peroxide was used. The soil microbial community, based on 16S rRNA gene copy number, was higher (7.1 × 10 6 copy number/g of bacteria, and 7.4 × 10 5 copy number/g of Archaea, respectively) in the hemoglobin catalyzed treatment. Our results show that TPH treatment in contaminated soil using hemoglobin catalyzed oxidation led to the enhanced removal effectiveness and was non-toxic to the native soil microbial community in the initial soil.