Generating Electric Current by Bioartificial Photosynthesis

Conjugated Polymer Enhanced Photoelectric Response of Self-Circulating Photosynthetic Bioelectrochemical Cell

A water-oxygen-water photosynthetic bioelectrochemical cell (PBEC) comprising hybrid poly(fluorene-alt-phenylene) (PFP)/PSII-enriched membranes (BBY) photoanode and bilirubin oxidase (BOD) biocathode has been designed and fabricated. In the PBEC, water is split into oxygen, protons, and electrons through light-dependent reaction of PSII at the photoanode, and oxygen is converted into water catalyzed by BOD at the biocathode, forming the electronic circuit and generating current. At the photoanode, PFP can simultaneously accelerate the photosynthetic water oxidation and the electron transfer between BBY and electrode. Interestingly, the photocurrent density produced by PBEC after the introduction of PFP reaches 1.05 ± 0.01 μA/cm², which is 2.5 times more than that of the BBY electrode, indicating that conjugated polymer can enhance the photoelectric response of PBEC.

Electrification of Biotechnology: Quo Vadis?

Electrobiotechnology has come a long way and has gained much interest among researchers all over the world. In the previous chapters of this book, an abundance of successful developments of lab-scale electrobiosynthesis and their underlying fundamentals are described. Thereby the individual needs and lines of research are highlighted. In this final chapter we will try to shed light on the overall performance of electrobiosynthetic processes with regard to their technological maturity, as well as the potential ecological and economic incentives for their industrial implementation.The evaluation of technical maturity, in particular, clearly demonstrates that electrobiosynthesis is still in its infancy. Bridging the "valley of death" between promising lab-scale results and first industrial applications as a market opener can only be achieved by the joint efforts of researchers from different disciplines in academia and industry, as well as by public funding and venture capital.Unfortunately, among other factors, the low degree of technical maturity hampers ecological evaluation, which so far has been limited to a small number of complete life cycle assessments. Therefore, we suggest using simplified evaluation tools (e.g., the environmental E-factor) to at least acquire clues about different parameters that influence the ecological impact. Ultimately, money makes the world go round and, hence, economic aspects will determine whether or not electrobiotechnological processes are implemented in industry. The existing examples show that different production routes based on electrobiosynthesis can become economically feasible.