Enzyme electrode, and bio fuel cell equipped therewith
An enzyme electrode having an electroconductive base member, an oxidoreductase and an electron mediator has at least a portion (a) in which the oxidoreductase is immobilized on the electroconductive base member, and a portion (b) in which the electron mediator is immobilized on the electroconductive base member but the oxidoreductase is not immobilized on the electroconductive base member. A bio fuel cell having the enzyme electrode as at least one of an anode and a cathode allows optimization of a reaction condition of each one of a plurality of reaction steps, including an “enzymatic reaction”, an “electron transfer reaction”, etc. Thus, the bio fuel cell provides high output.
1. A fuel cell comprising:
an enzyme electrode that incorporates a first electroconductive base member, a
second electroconductive base member, an oxidoreductase and an electron mediator; and
a fuel solution containing nicotinamide adenine dinucleotide as a coenzyme operable to assist the oxidoreductase, wherein
the enzyme electrode includes:
a first portion in which the oxidoreductase is immobilized on the first electroconductive base member;
and a second portion in which the electron mediator is immobilized but the oxidoreductase is not immobilized on the second electroconductive base member,
wherein the enzyme electrode includes a plurality of the first portions and a plurality of the second portions, and
the first portions and the second portions are alternately gathered into an aggregate.
2. The fuel cell according to claim 1 , wherein the first portion and the second portion is continuously alternate with each other.
3. The fuel cell according to claim 1 ,
wherein a shortest distance between the first portion and the second portion is less than or equal to 0.5 mm, in at least a portion of the enzyme electrode.
4. The fuel cell according to claim 1 , wherein the fuel cell is configured to employ the enzyme electrode as at least one of an anode electrode and a cathode electrode.
5. The fuel cell according to claim 4 , wherein:
the fuel cell is configured to employ the enzyme electrode as the anode electrode; and
a reduction starting potential of the electron mediator is greater than or equal to −0.32 V.
6. The fuel cell according to claim 4 , wherein:
the fuel cell is configured to employ the enzyme electrode as the cathode electrode; and
a reduction starting potential of the electron mediator is less than or equal to 1.2 V.
7. The fuel cell according to claim 1 , wherein
each of the first portions has a rod shape, and
each of the second portions has a rod shape.