A microbial fuel cell (MFC) uses bacteria to break down organic compounds found in waste water and generate an electric current. This is a sustainable way to generate power from waste material, with the potential of achieving over 50% energy efficiency. Our project will focus on genetically engineering the bacteria Shewanella oneidensis in ways that will make the microbial fuel cell more efficient. Our hopes that waste water can be inoculated with our transformed MR-1 to fuel the MFC.

According to the 2013 International Energy Outlook, energy demands will increase 56% by 2040. This rapidly growing demand for energy has sparked a search for sustainable and renewable energy sources. While many technologies are being developed to address this, some of the most intriguing are bioelectrochemical systems like the microbial fuel cell (MFC). The distinctiveness of bioelectrochemical systems come from their ability to simultaneously take on two ecological vices with: sustainable energy production, and waste-water treatment. The basics of how bacteria in an MFC produce electricity are understood, however we feel more research needs to be done to increase efficiency at the microbial level.

The most popular research for microbial fuel cells has been poised towards increasing the power density using more state-of-the-art synthetic materials in the structural design. Our project will focus on another aspect: modifying the microbes which are responsible for generating the electricity. Many of the current limiting factors of MFC performance comes from the bacteria themselves.

The first and most apparent limiting factor in an MFC is the surface area of the anode. The bacteria can only generate electricity when it is in direct contact with, or in close proximity to the surface of the anode. To take full advantage of the limited surface area, it is best for the bacteria to grow in a dense film called a biofilm. This leads to our goal:

We will also focus on the bacteria's ability to transfer electrons from the compounds in the waste water to the anode. From [7], we learned that biofilm degradation occurs in anaerobic conditions. In [7], the gene VcCD00034807 from Vibrio chlorea was expressed in MR-1 and shown to recover biofilm growth in anaerobic conditions. We plan to transform replicate the experiment done in [7] and grow the bacteria in an MFC to see if we can get a thicker biofilm and voltage output. Thickness will be measured by taking stack images with a confocal microscope and acquire the data using a digital multimeter and the ExcelINX software.
Results not available at this time. Will be presented at Jamboree.

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