Retention of Activity and Secondary Structure of Hyperthermophilic Laccase Adsorbed on Carbon Black

Further increases in the current density of biofuel cells are partly limited by the deactivation of enzymes upon adsorption on hydrophobic carbon materials. A hyperthermophilic enzyme, hyperthermophilic laccase, was employed in the present study and the change in the activities and secondary structures upon adsorption on carbon black (CB) were evaluated by the oxidation rate of 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) and by Fourier transform infrared spectroscopy, respectively, in comparison with the mesophilic enzymes, laccase from Trametes versicolor (denoted as mesophilic laccase), and glucose oxidase (GOx). Hyperthermophilic laccase retained its specific activities and secondary structures upon adsorption on CB compared with the other two enzymes mesophilic laccase and GOx.