High catalytic performance of laccase wired to naphthylated multiwall carbon nanotubes

The direct electrical connection of laccase on the electrode surface is a key feature in the design of efficient and stable biocathodes. However, laccase can perform a direct electron transfer only when it is in the preferred orientation toward the electrode. Here we report the investigation of the orientation of laccase from white rot fungus on multi-walled carbon nanotube surface modified with a naphthalene group. Naphthylated multi wall carbon nanotubes were synthesized and the kinetics of laccase from white rot fungus adsorption and its direct electro-catalytic activity toward oxygen reduction was investigated by QCM and electrochemical techniques. Compared to pristine multi-walled carbon nanotubes laccase shows a high affinity to be adsorbed onto the surface of naphthylated carbon nanotubes at a very fast rate. The subsequent wiring to the naphthylated multi-walled carbon nanotubes is accompanied by a reorientation and arrangement of adsorbed laccase to create a composite biocathode that exhibits a high-performance for oxygen reduction by direct electron transfer with maximum current densities of 3 mA cm−2. •We graft naphthalene molecules on MWCNTs.•We examine the kinetic of laccase adsorption on naphtylated MWCNTs.•We investigate the relationship between laccase adsorption and laccase electrical connection on naphtylated MWCNTs.•We examine electro catalytic performances of laccase modified naphtylated MWCNTs toward oxygen reduction.•We study the kinetic og the electro catalytic activity of adsorbed laccase toward oxygen reduction.