A thermostable humic acid peroxidase from Streptomyces sp. strain AH4: Purification and biochemical characterization

► The paper reports on a new peroxidase (HaP3) from a Streptomyces sp. strain AH4. ► HaP3 was a heme protein and a monomer with a molecular mass of 60,215.18-Da. ► The optimum pH and temperature values for activity were pH 5 and 80 °C, respectively. ► HaP3 activity was inhibited by the addition of sodium azide and potassium cyanide. ► HaP3 is a strong candidate for application in the biodegradation of humic acids.