Thermophilic

Flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenase (GDH) was identified and cloned from thermophilic filamentous fungi Talaromyces emersonii using the homology cloning method. A direct electron transfer bioanode composed of T. emersonii FAD-GDH and a single-walled carbon nanotube was produced. Enzymes from thermophilic microorganisms generally have low activity at ambient temperature; however, the T. emersonii FAD-GDH bioanode exhibits a large anodic current due to the enzymatic reaction (1 mA cm-2) at ambient temperature. Furthermore, the T. emersonii FAD-GDH bioanode worked at 70 °C for 12 h. This is the first report of a bioanode with a glucose-catalyzing enzyme from a thermophilic microorganism that has potential for biosensor and biofuel cell applications. In addition, we demonstrate how the glycoforms of T. emersonii FAD-GDHs expressed by various hosts influence the electrochemical properties of the bioanode.