Green Oxidation of Steroids in Nanoreactors Assembled from Laccase and Linear-Dendritic Copolymers (original) (raw)

This chapter describes our recent advances on the utilization of polymer-modified laccase complexes in aqueous systems towards the oxidation/polymerization of naturally hydro phobic steroidal compounds, Equilin (EQ) and 17-β-estradiol (β-EST). We elucidate the kinetic and synthetic aspects of the process with the model compound 5,6,7,8-tetrahydro-2naphthol (ΤΗΝ). The nano-reactor system is composed of linear poly(ethylene oxide)-dendritic poly(benzyl ether) diblock copolymer (G3-PEO13k) and laccase isolated from Trametes versicolor. Other advantages of the complex in comparison to the native enzyme are its recyclability, enhanced stability, activity, and overall simplicity in product harvesting and isolation. A principle of action of the complex is suggested based on these findings and is further supported by the biphasic solid-liquid nature of the reaction medium, which exhibits continuous influx of starting material and steady solid product expulsion. Comparative experiments with linear-linear poly(styrene)-block-poly(ethylene oxide) copoly mer under identical conditions do not evince formation of a 110