Cytochrome c-coupled photosystem I and photosystem II (PSI/PSII) photo-bioelectrochemical cells

Abstract

Photo-bioelectrochemical cells are devices that use biomolecule-modified electrodes for the conversion of solar light to electrical power. We present the construction of a layered assembly of the native photosynthetic reaction centers photosystem I (PSI) and photosystem II (PSII), crosslinked by polyvinyl pyridine/methyl pyridinium and cytochrome c (Cyt. c) that act as an electron transfer mediating layer. Electrostatic interactions and glutaric dialdehyde crosslinking of the protein layers stabilize the biomolecules on the electrodes. The irradiation of the PSII/Cyt. c/PSI-modified electrodes facilitates an electron transfer cascade, where photoexcited PSII leads to O2 evolution and to the reduction of Cyt. c, with the concomitant ejection of electrons from PSI to the electrode, and the reduction of the P700+ sites by the reduced Cyt. c units.