Characterization of the Coriolopsis gallica DyP for Its Potential to Biotransform Various Fluoroquinolones

Coriolopsis gallica (Cga) is a white-rot fungus renowned for its ability to secrete ligninolytic enzymes that are capable of oxidizing phenolic compounds. This study aimed to investigate the biochemical characteristics of a dye-decolorizing peroxidase named CgaDyP1 and test its ability to biotransform antibiotics. CgaDyP1 was cloned and heterologously expressed in Escherichia coli. We fully characterized the biochemical properties of CgaDyP1 and evaluated its dye-decolorizing potential to confirm that it belongs to the DyP class of enzymes. We also tested its fluoroquinolone antibiotic biotransformation potential for possible biotechnological applications. Alignment of the primary amino acid sequence with DyP homolog sequences showed that CgaDyP1 has high similarity with other fungal DyPs. The recombinant CgaDyP1 exhibited activity on substrates such as ABTS and 2,6-dimethoxyphenol (DMP) with optimal performance at a pH of 3, although activity at pH 2.5, pH 4, and pH5 diminished over time. Thermostability tests indicated that the enzyme remains stable at temperatures between 30 °C and 50 °C and retains 70% of its initial activity after 180 min at 50 °C. Tests on the effect of hydrogen peroxide on CgaDyP1 activity found peak activity at 0.25 mM H₂O₂. CgaDyP1 decolorized five industrial dyes, and kinetics data confirmed that it belongs to the DyP class of enzymes. CgaDyP1 was shown to biotransform some of the 7 recalcitrant fluoroquinolone antibiotics tested here, including levofloxacin, moxifloxacin, and norfloxacin, and thus holds potential for biotechnological applications.