A three-dimensional hybrid electrode with electroactive microbes for efficient electrogenesis and chemical synthesis.

Fang, Xin; Kalathil, Shafeer; Divitini, Giorgio; Wang, Qian; Reisner, Erwin · Proc Natl Acad Sci U S A · 2020

basic_science · Level V

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Abstract

Integration of electroactive bacteria into electrodes combines strengths of intracellular biochemistry with electrochemistry for energy conversion and chemical synthesis. However, such biohybrid systems are often plagued with suboptimal electrodes, which limits the incorporation and productivity of the bacterial colony. Here, we show that an inverse opal-indium tin oxide electrode hosts a large population of current-producing <i>Geobacter</i> and attains a current density of 3 mA cm<sup>-2</sup> stemming from bacterial respiration. Differential gene expression analysis revealed <i>Geobacter</i>'s transcriptional regulations to express more electron-relaying proteins when interfaced with electrodes. The electrode also allows coculturing with <i>Shewanella</i> for syntrophic electrogenesis, which grants the system additional flexibility in converting electron donors. The biohybrid electrode containing <i>Geobacter</i> can also catalyze the reduction of soluble fumarate and heterogenous graphene oxide, with electrons from an external power source or an irradiated photoanode. This biohybrid electrode represents a platform to employ live cells for sustainable power generation and biosynthesis.