Carbon superfine materials as a promising material for Gluconobacter oxydans based microbial fuel cells

We have investigated the properties of a several bioelectrodes based on the immobilization of Gluconobacter oxydans bacterial cells on carbon superfine materials (CFMs). We use three types of CFMs (as adopted by the working classification CFM 1-3). All bioelectrodes was formed by covering the surface of the CFM via suspension of bacteria in a chitosan gel. The properties of samples are evaluated by measuring the physiological state of the bacteria immobilized: (a) recording the intensity of cellular respiration, (b) for measuring the charge transport characteristics of electrode (bioelectrocatalysis), and (c) by measuring the electrode impedance. Measurements (b) and (c) are made on two and three-electrode circuits in the oxidation of ethanol in the presence of 2,6-dichlorophenol electron transport mediator. For CFMs 1 and 2 the electron transport by the oxidation of the substrate is not registered, while for CFM 3 the current generation occurs. The resistance of CFM 3 bioelectrode is below the resistance of CFMs 1 and 2 both before (39.6 k Omega/cm(2) for CFM 3, 630 Omega/cm(2) for CFM 2, and 1329 Omega/cm(2) for CFM 1) and after the addition of the substrate (2.9 k Omega/cm(2) for CFM 3, 45 k Omega/cm(2) for CFM 2, and 58 k Omega/cm(2) for CFM 1). The bioelectrode made of CFM 3 has a capacitance of 196 mu F/cm(2)-greater than two orders of magnitude of the bioelectrode capacity of CFMs 1 and 2 (0.51 and 0.58 mu F/cm(2), respectively). It is important to further study the properties of the CFM class of materials, which are promising as the basis of mechanically flexible electrodes with controlled parameters.