Close-Packed Nanowire-Bacteria Hybrids for Efficient Solar-Driven CO2 Fixation

Abstract

Microbial electro-and photoelectrochemical CO2 fixation, in which CO2-reducing microorganisms are directly interfaced with a cathode material, represent promising approaches for sustainable fuel production. Although considerable efforts have been invested to optimize microorganism species and electrode materials, the microorganismcathode interface has not been systematically studied. Here, investigation of the interface allowed us to optimize the CO2-reducing rate of silicon nanowire/Sporomusa ovata system. Tuning the bulk electrolyte pH and increasing its buffering capacity supported the formation of a close-packed nanowire-bacteria cathode. Consequently, the resulting closepacked biohybrid achieved a CO2-reducing current density of ~0.65 mA cm-2. When coupled with a photovoltaic device, our system enabled solar-to-acetate production with ~3.6% efficiency over seven days.

A Living Biotic–Abiotic Composite that can Switch Function Between Current Generation and Electrochemical Energy Storage

“…Relevant features for considering the CPE‐K/ S. oneidensis composite include: 1) CPE‐K can form a 3D conducting hydrogel network that promotes S. oneidensis to respire and generate electricity; [ 25 ] 2) the conducting polyelectrolyte network may be used for charge storage via doping and de‐doping of the conjugated polyelectrolyte backbone; [ 32 ] 3) both polyelectrolyte [ 24,33 ] and bacteria [ 34,35 ] change their properties in response to various external stimuli, such as temperature, electric fields, and ionic strength and composition of the solution. The latter will be shown here to be advantageous for achieving targeted properties and realizing function switching purposes.…”

Semi-biological approaches to solar-to-chemical conversion

“…248 Recently, the acetate production was accelerated as a result of a larger bacterial population and a better bacterium-nanowire interface, which was realised by improving the local pH environment inside the electrode. 250 As such, the solar-to-chemical conversion efficiency was increased to 3.6% over seven days when coupling to a photovoltaic device.…”

Choice of Microbial System for In-Situ Resource Utilization on Mars

“…Anaerobic (homo)acetogens (like, e.g. Sporomusa ovata) have a lower metabolic rate and are less genetically tractable, but also have a remarkable substrate range in addition to their unique reductive acetyl-CoA pathway, the latter making them attractive to directly convert CO and/or CO 2 to organic acids and alcohols (Schuchmann and Müller, 2016;Su et al, 2020). Certain PPBs are even more flexible in terms of carbon-and energy-source (chemo-, auto-/heterotrophic), capable of anoxygenic photosynthesis, oxidize carbon monoxide, and are in addition also diazotrophic.…”