about this project

During the beginning of the semester we were sitting around scratching our heads as we thought about current problems that are facing our world today. Through much deliberation we were finally able to settle on a central theme: energy production. Looking through the literature and past iGEM projects we saw many different ways in which this problem could be approached, however, one such method caught our eyes: microbial electrochemical technologies, specifically microbial electrolysis cells (MEC’s). A project focused on the improvement and production of a MEC not only would contribute to clean energy production but was also a multifaceted and interdisciplinary approach in which many Northeastern undergraduates could participate.

Microbial Electrochemical Technologies

Microbial electrochemical technologies take advantage of bacterial oxidation of food sources by the production of electrical current. Microbial electrolysis cells, which are a subset of microbial electrochemical technologies, use the electrical current generated by bacteria metabolizing substrate. This biologically generated electrical current can serve used as a substitute subsidy for the evolution of valuable chemicals typically used on the cathode inside of the cell.

Hydrogen normally requires an input of approximately 0.41V to be produced using acetate. In a MEC hydrogen can be produced at approximately 0.2V due to the bacteria providing a portion of the current. However, when oxygen is introduced into the MEC system hydrogen generation is hindered because oxygen readily reduces at the cathode. Maintaining an oxygen-free environment, through co-culturing the bacteria producing the current with bioengineered oxygen scavenging E. coli, may prove advantageous for MEC’s.

Power Loss in the Cell

A major source of power loss in MEC’s is derived from incomplete proton transfer from anode to cathode. This reduces the efficiency of the electrochemical reaction and creates local pH gradients that cause harm to the bacteria on either electrode. Exporting protons at the cathode can help neutralize basicity caused by the reduction reaction and would provide more substrate for hydrogen generation. To solve this issue we proposed to engineer the oxygen scavenging E. coli surrounding the cathode to produce proteorhodopsin, which would act as a proton pumping mechanism inside the cell.

Practical Application of our MEC

In thinking about practical applications of microbial electrolysis cells we determined that our MEC would be the most beneficial when implemented in wastewater treatment facilities. In these facilities there is an abundance of reduced organic material that has the potential to be recycled into energy.

who we are

Northeastern University’s iGEM Team is made up of students from various different backgrounds and experience levels who have come together with a shared goal of learning more about bioengineering and biological research. From first years to graduating seniors, from computer science majors to chemical engineering majors, all members have used their diverse pool of knowledge to contribute to this project and make it greater than the sum of its parts.

The team has been supported by graduate students advisers, faculty advisers, and iGEM teams from other institutions, details of which can be seen on the team page, attributions page, and collaborators page.