Decolorization of an anthraquinone dye by the recombinant dye-decolorizing peroxidase (rDyP) immobilized on mesoporous materials

A recombinant dye-decolorizing peroxidase (rDyP) produced from Aspergillus oryzae is a novel peroxidase because of its unique tertiary structure. No conventional immobilization of rDyP has been successful. In this study, immobilization of rDyP was conducted using silica-based mesoporous materials, FSM-16 and AlSBA-15. Adsorption yields of rDyP immobilized on the two materials increased as pH decreased from 6 to 3. However, the activity yield of immobilized rDyP decreased with decreasing pH. Therefore, overall efficiency which is defined as adsorption yield × activity yield was maximum for immobilized rDyP on FSM-16 at pH 5 and on AlSBA-15 at pH 4. Leaching of rDyP from FSM-16 was much lower than that from AlSBA-15 presumably because FSM-16 has a more anionic surface, leading to stronger affinity of rDyP to FSM-16. rDyP immobilized on FSM-16 at pH 4 decolorized eight sequential batches of an anthraquinone dye, Remazol Brilliant Blue R (RBBR) in repeated-batch decolorization, but only two batches for RBBR occurred by rDyP immobilized on AlSBA-15 because of leaching rDyP from AlSBA-15.