Electron production with E. coli and proteorhodopsin

The aim of our project is to develop a pseudoautotrophic E. coli, enabling it to live in the microbial fuel cell anaerobic condition. Our idea is to engineer E. coli with proteorhodopsin, a light-powered proton pump identified in bacteria that live in deep waters. This protein is activated by light and needs retinal molecules to pump protons outward following excitation. Thus we want to engineer our bacteria with blh, that encodes for the enzyme that cleaves beta-carotene and produces retinal.

To increase electron production we plan to overexpress pncB that represents the limiting step in the NAD+ synthesis pathway. The more NAD+ is produced, the more electrons are transported by NADH. In short: light activates proteorhodopsin, increases bacterial viability, and drives to a more efficient electron production. Our bacterial device will give rise to a self-sustainable system, powered by sunlight during the day and by a light bulb at night. Daytime-electricity can be either used or stored to be employed as a power source for the lightbulb at night.