Biocatalysts are increasingly applied in chemical synthesis due to their high level of regioselectivity and enantioselectivity. P450s are important biocatalysts due to their ability to hydroxylate unactivated carbon atoms using molecular oxygen. P450s catalyze monooxygenation reactions by using nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) as electron donor and electron transfer proteins. P450s can also utilize hydrogen peroxide (H2O2) instead of NAD(P)H and redox partners through a H2O2-shunt pathway. However, P450s are inefficient in oxygenation reactions with H2O2. Thermophilic enzymes demonstrates high stability at different temperatures, pH and organic solvents, so it is expected to increase implementations of enzymes. CYP119 is an acidothermophilic P450 from Sulfolobus acidocaldarius. In our laboratories, directed evolution was used to create improved mutants of CYP119 with higher oxidation activity when using H2O2. T213R/T214I CYP119 was such a variant. The aim of the study is investigations of T213R/T214I CYP119 whether it is a stable and efficient biocatalyst for selective oxidation of hydrocarbons, which does not require expensive cofactors and electron transfer proteins or not. T213R/T214I CYP119 was expressed and isolated under optimized conditions. Peroxidase activity of T213R/T214I CYP119 was tested and compared to wild type (WT) CYP119. Characterization of T213R/T214I CYP119 shows higher peroxidation activity of enzyme for Amplex® Red, guaiacol and ABTS and epoxidation of enzyme for styrene substrates compared to CYP119. T213R/T214I CYP119 have higher affinity for progesterone and lower affinity for lauric acid. Mutations on Thr213 and Thr214 residues the active site will shed light on the design of novel CYP119 mutants in the future.