Preparation of horseradish peroxidase-inorganic hybrid nano structures (nanoflowers), investigation of catalytic activities and stability

In order to use the enzymes continuously, their activity, stability and recovery should be increased. Their application is limited due to the disadvantages that free enzymes are difficult to separate and reuse from the reaction medium. Enzyme immobilization has been one of the many methods used to address all these limitations. In this study, hybrid nano-flower structures were synthesized using horseradish peroxidase (HRP) enzyme using Cu2 +, Ca2 + and Mn2 + ions. The synthesized hybrid nanoflowers were crosslinked with glutaraldehyde and the kinetic parameters were determined by determining the reusability, substrate specificity and enzyme escape rates of all hybrid nanoflowers at optimum pH, temperature, dye removal. SEM, FTIR, XRD and EDX analyzes were performed in the characterization studies of synthesized hybrid nanoflowers. When SEM images were examined; flower-shaped CuNF-HRP, CaNF-HRP and MnNF-HRP hybrid nanoflower structures were observed. When hybrid nano-flower structures cross-linked with glutaraldehyde were examined; According to the normal hybrid nano-flower structures were reduced in size, pores tightened. The immobilization yields of the synthesized hybrid nanoflower structures were found to be 91% for CuNF-HRP, 88% for CaNF-HRP and 85% for MnNF-HRP. In the optimization studies, the optimum temperature value of free and immobilized nano-flower structures was found to be 40 ° C and the optimum pH value was 6.0. KM and Vmax of the free enzyme were 25.16 mM and 22.27 U / mL, respectively. In hybrid nanoflower structures, KM and Vmax values for CuNF-HRP were 30.53 mM and 5.63 U / mg, KM and Vmax values for CaNF-HRP were 34.24 mM and 5.51 U / mg, KM and Vmax for MnNF-HRP. 31.83 mM and 4.95 U / mg. In the second part of the study, dye removal and phenolic compound oxidation were performed in order to investigate the catalytic performance of hybrid nanoflower structures. Amarant, Tartrazine and Crystal Viole model paints were used for dye removal. Catechol, Pyrogallol, L-Tyrosine, Phenol and Guaiacol phenolic compounds were used for phenol oxidation. It was determined that the immobilized enzymes produced dye removal in 80-96% and phenolic compound oxidation in 65-91%.