Renewable Energy Source: Residents In Your Stomach

How cool is carrying a power and sewage treatment plant in your stomach wherever you go? Our microbe friends might just allow us to do that.

The microbial fuel cell (MFC) is a renewable energy system that uses microorganisms to generate electricity. According to Beth Daley, the editor of The Conversation U.S., MFCs work quite similarly to batteries. Similarly, MFCs consist of one positive side and one negative side. An external conductive circuit connects the two sides of the MFC. The conductive circuit captures the electrons released by microbes when they break down organic matter, and this accounts for electricity generation. 

Typically, electricity-producing microorganisms are found mainly in anaerobic habitats for producing electricity in MFCs; however, Mehdi Tahernia, a scientist at the bioelectronics and microsystems laboratory of  Binghamton University, suggests that a group of “weak” conductive bacteria, known as Gram-positive bacteria, may also qualify for the job. 

Gram-positive bacteria were previously believed to be weak conductors because the layers surrounding the cells (known as cell walls) are thick and not capable of conducting electricity. Yet the recent realization of how Gram-positive bacteria transfer their electrons brought to light the possibility of using them in MFCs. 

What’s fascinating is that some of these Gram-positive bacteria are found in our guts! The human gut provides our bacteria friends with their happy place: an oxygen-poor yet nutrient-rich environment. Scientist Mehdi Tahernia claims that this anoxic environment turns out to be ideal for microbes to release and transfer electrons outside of the cell. Perhaps one day we could start charging our phones with the help of the residents that live inside of our stomachs. At that time, another function of the human stomach would possibly emerge in the field of physiology—producing electricity. 

Moreover, the ideal organic matter for our microbe friends to break down to release electrons exist in wastewater. A wide variety of substances in wastewater could be used to “feed” microbes, ranging from simple compounds to complex mixtures. This opens up opportunities for MFCs and Gram-positive bacteria to not only produce renewable electricity but also purify water at the same time. 

Even so, why bother? 

According to Hannah Ritchie and Max Roser, the founder of Our World in Data, fossil fuels account for two-thirds of electricity generation worldwide. However, we cannot rely on fossil fuels to charge our phones and light our homes in the long run because they are non-renewable energy, meaning that one day they will run out. Renewable energy today accounts for one-third of global electricity generation, which is not enough to satisfy the world’s electricity demand if fossil fuels are depleted one day. Consequently, we must discover more clean electricity sources like MFCs to power the world.

Polluted water also contributes to nitrogen pollution, which harms both marine animals and mammals; sewage, furthermore, threatens the health of human beings. Dr. Johnson, a virologist from the University of Missouri, remarks that sewage and untreated water increase the risk of diseases occurring and spreading. MFCs might just be the perfect helper to ease the burden of wastewater on the Earth and all living things. 

So, the next time you turn on your light switch, think about our microbe friends. Perhaps in the future, they would be powering your home or doing something much, much more magnificent.

Works Cited:

Anthes, E. (2021, May 7). From the wastewater drain, solid pandemic data. The New York Times. https://www.nytimes.com/2021/05/07/health/coronavirus-sewage.html

Obileke, K., Onyeaka, H., Meyer, E. L., & Nwokolo, N. (2021). Microbial fuel cells, a renewable energy technology for bio-electricity generation: A mini-review. Electrochemistry Communications, 125(107003), 107003. https://doi.org/10.1016/j.elecom.2021.107003

Ritchie, H., Roser, M., & Rosado, P. (2022). Energy. Our World in Data. https://ourworldindata.org/electricity-mix

Tahernia, M., Plotkin-Kaye, E., Mohammadifar, M., Gao, Y., Oefelein, M. R., Cook, L. C., & Choi, S. (2020). Characterization of electrogenic gut bacteria. ACS Omega, 5(45), 29439–29446. https://doi.org/10.1021/acsomega.0c04362