Alcohol Dehydrogenase as a Model System

In 2011, alcohol dehydrogenase (ADH) was used as a model enzyme coupled with poly (MG) for NADH reoxidation in the construction of a three-dimensional BFC with ethanol as fuel [103]. In combination with an air-breathing/gas difhision cathode (using laccase as an oxygen reduction enzyme), a BFC was fabricated that was able to successfully exploit ethanol oxidation by an NAD -dependent ADH, immobilized by entrapment in a multiwaUed CNT (MWCNT)/chitosan matrix [106]. The feasibility and reproducibUity of the resulting BFC were demonstrated in 2008 with a series of standardized multilaboratory experiments [96]. 

Large ohmic losses are observed with the ADH anode revealed by a polarization curve that depicts resistive behavior and a BFC that is anode limited. This ohmic 

FIGURE 4.7 Polarization curves of (A) ADH anode, ( ) laccase cathode, and ( ) the fully assembled biological fuel cell. Dashed line represents the theoretical full cell polarization curve. Ethanol concentration 475 mM open-circuit voltage=0.618 V. (Reprinted with permission from Ref. [103]. Copyright 2011, Elsevier.) 

ANODIC CATALYSTS FOR OXIDATION OF CARBON-CONTAINING FUELS 

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