Chapter 7
Applications to Biofuel Cells
and Bioreactors
Abstract This chapter starts by introducing several types of biofuel cells as an application of bioelectrocatalysis with the advantages and disadvantages. Challenging
issues and outlook are also described. Photo-driven bioanodes and bio-solar cell are
also introduced. Bioelectrochemical reactors are proposed as reverse reactions of
biofuel cells. One of brilliant points of bioelectrocatalytic systems is the property
that the systems can catalyze redox reactions bidirectionally and reversibly. The
significance of this matter is discussed in view of hydrogen society.
Keywords Biofuel cells · Biosupercapacitors · Bioreactors · Bidirectional
catalysis · Hydrogen society · C1 cycle · NAD(P)-dependent enzymes
7.1 From Bioelectrocatalysis to Biofuel Cells
and Bioreactors
As mentioned in Chap. 1, bioelectrocatalysis utilizes redox enzymes to provide nonspecific electrode processes with specific catalytic activities, and the system can be
applied not only to biosensors (signal transformation) but to varieties of electrochemical devices for the transformation of chemical energy of fuels to electrical energy
or vice versa. The former is usually called as biological fuel cells (which is simply
referred to as biofuel cells) and, the latter is named as bioelectrochemical reactors (which is simply referred to as bioreactors). Although some microbes (strictly
speaking, a set of cascade redox enzymes in the microbes) are also often employed
for energy conversions, this chapter deals only with biofuel cells and bioreactors that
utilize purified redox enzyme(s).
7.2 Biofuel Cell
The concept of biofuel cells was first introduced by Yahiro and co-workers in 1964
[1]. Generally, biofuel cells consist of a two-electrode setup: with the aid of corresponding redox enzymes, fuels are oxidized at the bioanode, and the electrons flow
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
K. Kano et al., Enzymatic Bioelectrocatalysis,
https://doi.org/10.1007/978-981-15-8960-7_7
115
Applications to Biofuel Cells
and Bioreactors
Abstract This chapter starts by introducing several types of biofuel cells as an application of bioelectrocatalysis with the advantages and disadvantages. Challenging
issues and outlook are also described. Photo-driven bioanodes and bio-solar cell are
also introduced. Bioelectrochemical reactors are proposed as reverse reactions of
biofuel cells. One of brilliant points of bioelectrocatalytic systems is the property
that the systems can catalyze redox reactions bidirectionally and reversibly. The
significance of this matter is discussed in view of hydrogen society.
Keywords Biofuel cells · Biosupercapacitors · Bioreactors · Bidirectional
catalysis · Hydrogen society · C1 cycle · NAD(P)-dependent enzymes
7.1 From Bioelectrocatalysis to Biofuel Cells
and Bioreactors
As mentioned in Chap. 1, bioelectrocatalysis utilizes redox enzymes to provide nonspecific electrode processes with specific catalytic activities, and the system can be
applied not only to biosensors (signal transformation) but to varieties of electrochemical devices for the transformation of chemical energy of fuels to electrical energy
or vice versa. The former is usually called as biological fuel cells (which is simply
referred to as biofuel cells) and, the latter is named as bioelectrochemical reactors (which is simply referred to as bioreactors). Although some microbes (strictly
speaking, a set of cascade redox enzymes in the microbes) are also often employed
for energy conversions, this chapter deals only with biofuel cells and bioreactors that
utilize purified redox enzyme(s).
7.2 Biofuel Cell
The concept of biofuel cells was first introduced by Yahiro and co-workers in 1964
[1]. Generally, biofuel cells consist of a two-electrode setup: with the aid of corresponding redox enzymes, fuels are oxidized at the bioanode, and the electrons flow
© The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2021
K. Kano et al., Enzymatic Bioelectrocatalysis,
https://doi.org/10.1007/978-981-15-8960-7_7
115