Investigation of graphite electrodes modified with cellobiose dehydrogenase from the ascomycete Myriococcum thermophilum

The catalytic properties of cellobiose dehydrogenase (CDH) from the ascomycete fungus Myriococcum thermophilum adsorbed on a graphite electrode were investigated for a large variety of carbohydrate substrates. The effects of applied potential, pH and buffer composition were tested and optimized, and the most suitable conditions were used to evaluate the detection limit, linear range, and sensitivity of the sensor for different carbohydrates in the flow injection mode. Subsequently, the long term stability of the modified electrodes was determined. Additionally, the direct and mediated electron transfer between the active site of the enzyme and the electrode has been investigated by amperometric flow injection measurements in the absence and presence of the mediator 1,4-benzoquinone in the presence of cellobiose or lactose.