Category ENEV P20 Comparing the Electricity Output in Microbial Fuel Cells by

Bacteria Type

Abstract This experiment tested the voltage generated by different types of

bacteria in microbial fuel cells. Microbial fuel cells are an alternative

energy source to fossil fuels and they use organic waste to generate

electricity. This is done using bacteria that consume the organic waste

and energy and electrons. However, microbial fuel cells are not efficient

enough for practical use as the amount of electricity they generate

changes over time and the soil bacteria that are commonly used in

these fuel cells aren't always easy to obtain in isolated samples. This is

why four other types of soil bacteria were used in this project. The

types of bacteria that were used were Rhodospirillum rubrum,

Clostridium beijerinckii, Pseudomonas putida, and Mycobacterium

nonchromogenicum. R. rubrum is facultatively anaerobic and due to the

versatility in the ways that it gets energy from food, it was hypothesized

that this bacteria would generate the highest voltage.

A different type of bacteria was added to nutrient broth in the anode

chamber of each microbial fuel cell. There were three trials, or three

microbial fuel cells for each type of bacteria. A multimeter was used to

record the voltage generated by each trial for three days. With an

overall average of .0707 volts, R. rubrum generated the highest voltage

and the hypothesis was supported. The data shows that the voltages

generated were low, so in the future an electron- extracting mediator

can be tested to improve voltages. This data can help improve the

efficiency of microbial fuel cells by providing data on more easily

obtained bacteria that can be used in microbial fuel cells.

Bibliography http://journal.frontiersin.org/researchtopic/3845/electrochemically-

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http://chemistry.stackexchange.com/questions/5477/why-is-it-important-

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http://www.sciencebuddies.org/science-fair-projects/electricity-

magnetism-electromagnetism-tutorial#currentelectricity

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projects/project_ideas/Energy_p026.shtml#background

https://microbewiki.kenyon.edu/index.php/Rhodospirillum_rubrum

https://en.wikipedia.org/wiki/Pseudomonas_putida

https://en.wikipedia.org/wiki/Microbial_fuel_cell#Mediator-free

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