Background

Biosensing Water Contaminants with Genetically Engineered Shewanella oneidensis MR-1

As one of the most important natural resources, the declining quality of fresh water is a world-wide issue. Pollutants such as pharmaceuticals, hormones and heavy metals are rarely monitored and the need to detect and remove these compounds in an inexpensive way is what motivates this project. The marine bacterium Shewanella oneidensis MR-1 could be a part of the solution through its unique ability to interact with electronics. The Mtr pathway in S. oneidensis MR-1 is an external electron transportation pathway that is able to transfer electrons to an external acceptor such as an anode, thus generating electric current that is utilized in bioelectrochemical systems. We are utilizing S. oneidensis MR-1 △MtrB, the MtrB gene is removed, to prevent electron flow to an outside source through this key protein. We are then inserting a plasmid into this strain that contains the MtrB gene under control of a promoter that activates transcription of the protein when induced by compounds such as pesticides and metals in the water. This will allow for controlled electrical expression that can be used in microbial fuel cells to create a biosensor for the detection of these compounds. This biosensor will then be engineered to be manufactured on a large scale to be used for research, education, humanitarian efforts and even consumer use. Although the proof of concept is currently tested in a single chambered bioelectrochemical system, an affordable and portable paper microbial fuel cell system is currently in development.