Biocatalysis 2018; 4: 1-13 and temperatures below 30°C. An interesting property of the catalyst was oxidation observed in the absence of hydrogen peroxide. Keywords: dye-decolorizing peroxidase, enzyme kinetics, two-substrate enzyme, enzyme degradation, catalyst inhibition Graphical abstract: 1 Introduction The phylum of Basidomycota incorporates a plethora of fungi. Notable members are the white-rot and brown-rot fungi, which have been reported to be capable of secreting an interesting enzymatic cocktail in the extracellular medium with potential applications for industry [1]. This compendium of high redox potential biocatalysts is commonly referred to as the fungi’s ligninolytic system and is comprised of different types of peroxidases, laccases, and oxidases. In nature, the biocatalysts work synergistically to depolymerize the highly abundant, but recalcitrant to degradation, aromatic 3-d network polymer https://doi.org/10.1515/boca-2018-0001 Received December 3, 2017; accepted January 9, 2018 Abstract: A novel Dye-decolorizing peroxidase from the basidiomycete Pleurotus sapidus was screened for dye- decolorizing peroxidase activity with 2,2‘-azino-bis(3- ethylbenzothiazoline-6-sulfonic acid), Remazol Brilliant Blue R and Guaiacol. Additionally, the catalytic efficiency on degrading β-carotene into volatile products, and the catalyst storage stability with three different additives were also studied. The apparent inhibition constant (KS) was 51.7 µM. Optimal reaction rates (V max ) and affinity constants (Km) towards the reducing substrates were obtained using Michaelis-Menten kinetic theory. The trend in the calculated Km’s was found to be 7.0 mM > 0.524 mM > 0.051 mM for Guaiacol, 2,2‘-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and Remazol Brilliant Blue R. The storage stability of the catalyst was evaluated with 7.0% w/v PEG400, 7.0% w/v PEG1450 and 0.1% w/v Tween®80 at 5°C over a period of 45 days. The study revealed the longest activity conservation with PEG1450, where rDyP had lost 30% of initial activity. The enzyme solution presented similar pH and temperature dependence to known fungal dye-decolorizing peroxidases with most prolific enzymatic activities registered at pH 4.0 Research Article Open Access © 2018 Alexandru Avram et al., published by De Gruyter Open. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 License. Alexandru Avram, Arijit Sengupta, Peter H. Pfromm, Holger Zorn, Patrick Lorenz, Tatjana Schwarz, Khanh Quoc Nguyen, Peter Czermak* Novel DyP from the basidiomycete Pleurotus sapidus: substrate screening and kinetics *Corresponding author: Peter Czermak, Institute of Bioprocess Engineering and Pharmaceutical Technology, University of Applied Sciences Mittelhessen, Wiesenstrasse 14, Giessen, Germany, 35390, E-mail: peter.czermak@lse.thm.de Alexandru Avram, Arijit Sengupta, Ralph E. Martin Department of Chemical Engineering, University of Arkansas, Fayetteville, Arkan- sas, 72701 Peter H. Pfromm, Peter Czermak, Department of Chemical Enginee- ring, Kansas State University, Manhattan, Kansas, 66506 Holger Zorn, Peter Czermak, Institute of Food Chemistry and Food Biotechnology, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 17, Giessen, Germany, 35392 Holger Zorn, Peter Czermak, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Project Group Bioresources, Winchesterstrasse 2, Giessen, Germany, 35394 Patrick Lorenz, Tatjana Schwarz, Khanh Quoc Nguyen, AB Enzymes GmbH, Feldbergstrasse 78, Darmstadt, Germany, 64293