brindhaaa
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Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Mon Nov 02, 2020 11:14 pm

Hello,

My name is Brindha Srivatsav and I am a 9th grader. I am a part of my school's Science Research program and I have a project in mind, but I have a few questions.

I found this project on ScienceBuddies and will be making it a different variation.

First, let me go step by step with my understanding. An overview of my project is as below:

What if there was a way to generate electricity from the electrons of mud. Using a microbial fuel cell, electrons can be collected from anaerobic bacteria. In the anode chamber of the microbial fuel cell circuit, the anaerobic bacteria will consume organic waste material while extracting electrons from it and oxidizing it into CO2. As a part of its digestive process, the bacteria will create protons and electrons. The electrons will be pulled out of the solution and put onto the cathode and anode external circuit. Meanwhile, the cathode chamber will hold a conductive saltwater solution. The protons that are generated by the bacteria will be pulled out and will travel through the PEM, to meet with the electrons at the cathode. As the protons and electrons meet, they will form electricity, and leave behind clean water in the process.

A more detailed explanation can be found in this link on the "Background" tab:
https://www.sciencebuddies.org/science- ... background

The main part I am not sure about is which bacteria would be safe enough to pass a pre-approval and would, at the same time, consume the mud and produce protons and electrons to generate electricity.

Although most of these terms are new to me, this topic seemed to interest my research very much, and if anyone could help me proceed with this project, that would be incredibly helpful.

Thank you,
Brindha

koneill18
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby koneill18 » Tue Nov 03, 2020 9:47 am

Hi Brindha,

This sounds like a really cool and exciting project! The mud sample that you'll be collecting already has bacteria in it so you don't have to worry about adding bacteria yourself! The mud naturally contains anaerobic bacteria that are electrochemically active, so you can just collect the sample and you're good to go.

I hope this helps! Feel free to ask us any other questions you have as you continue on with the project!
Katelyn

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Tue Nov 03, 2020 10:50 pm

Thank you so much for your help!

I also have one more question that I was hoping you could answer.

If the bacteria is inside of the mud itself, then would I have to separate it from the mud in order for it to consume it and create protons and electrons? If so, do you have an idea of how I could do that at home?

Thank you so much!

Brindha

koneill18
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby koneill18 » Tue Nov 03, 2020 10:57 pm

Hi Brindha!

Nope, you don't have to separate the bacteria from the mud. You just have to put the mud into the anode chamber and you're good to go. The bacteria will do their thing without you having to manipulate them at all.

I hope this helps!
Katelyn

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Sat Nov 28, 2020 12:06 pm

Thank you so much for your response!

Over the past few weeks, I have researched anaerobic bacteria, processes of microbial fuel cells, and anaerobic respiration. However, I found that this project has already been tested. Since I will be entering my county's science fair, I would like to make my project unique. Due to this, I will have to find something to prove/test in my fuel cell.

My main issue is that I am not sure what I want to prove/test. I have a few ideas in mind, but I am also looking for something more advanced to possibly place in the science fair. Would you have any recommendations as to what I can do?

I also have one more question regarding increasing the output energy of my fuel cell. I read on several articles that including an aerobic air pump will increase the efficiency of the microbial fuel cell. However, I am not sure how I will add this to my design as I am planning to follow the instructions for building my MFC on the ScienceBudies MFC project I mentioned in a different post. Do you have an idea of how I would incorporate this?

Thank you so much for the time to answer my questions.

-Brindha

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Sun Nov 29, 2020 8:18 pm

I also have one more question. Is a microbial fuel cell the same thing as a galvanic cell? I read articles on how a galvanic cell works and they said this type of electrochemical cell had to have two metals in it. In a MFC, the same redox reactions occur and electricity is also generated by the flow of electrons from the anode to cathode, but there is no solid metal. Instead, there is mud in one chamber and stream water in the other. I am a bit confused about the difference between the two cells and I need a better understanding of it. Thank you so much, once again.

-Brindha

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Finding a Variable For My Microbial Fuel Cell

Postby brindhaaa » Mon Nov 30, 2020 2:30 pm

Hello,

My name is Brindha Srivatsav and I am a 9th grader. I am a part of my school's Science Research program. For my project this year, I will be creating three microbial fuel cells in which one will be the constant and the other two I will test different variables. For the most part, I will be following the "Waste Not, Want Not: Use a Microbial Fuel Cell to Create Electricity from Waste" ScienceBuddies project for building the MFC. A detailed explanation of my project and procedures can be found here:

https://www.sciencebuddies.org/science- ... background

My main issue is that I am not too sure what I want to test in the two MFC's. I read on articles that some sort of nitrate could help produce more electricity, but I cannot use fertilizers because I did not fill out Pre-Approval forms for my project since I did not think I would need them. I may add yeast extract in one MFC and a sugar solution in the other MFC to see if there is an increase in overall voltage output. However, I do not understand the science behind that so if someone could explain that to me, that would be very helpful.

I am not entirely sure I want to have these variables as I want to test something a little more promising to enhance the MFC and advanced- if there is anything - but I would need help figuring out what that is. My main goal is to place in the school science fair, and if anyone could help me think of an idea for my problem, it would be great.

Thank you so much,
Brindha

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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby MadelineB » Mon Nov 30, 2020 3:39 pm

Hi Brindha,

I merged your new question with the thread for the topic for your previous questions. Keeping your posts on this topic together helps the experts who were helping you more easily see that you have a follow-up question.

Thanks!
Madeline
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brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Tue Dec 01, 2020 12:24 pm

Ok, thank you for letting me know!

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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby koneill18 » Tue Dec 01, 2020 6:36 pm

Hi Brindha,

It sounds like you have some great ideas for improving your project! Testing how different substances increase the fuel cell’s power output is a good way to take the project to the next level. You can definitely test the sugar solution in one of your fuel cells. Bacteria break down the sugars and micronutrients in the soil using a process called cellular respiration. The sugars get broken down into electrons that are released from the bacteria and back out into the soil. So, if you add more sugars to the mud, it should give the bacteria more to eat so they’ll produce more electrons and increase the power output of the fuel cell. Here’s a link to an explanation of microbial fuel cells that talks about cellular respiration if you want more details on the process.
https://letstalkscience.ca/educational- ... fuel-cells

You’re right that nitrates also seem to enhance power output. If you can’t use fertilizer, you might be able to use plant debris, such as grass clippings or vegetable scraps, as a source of nitrates. Your idea to use yeast extract will probably work as well. Yeast extract is often used as a nutrient source in bacterial cell culture media, so giving the bacteria in the mud this extra nutritional supplement will probably also increase power output. There are fuel cells that use yeast as a source of electrons instead of bacteria since they can also break down the sugars in the soil and produce electrons. You could try building two fuel cells- one with bacteria and one with yeast- and see how the two compare in terms of power output. If you do a web search for “yeast microbial fuel cell,” you can find procedures explaining how to make one. But if you wanted to stick with the procedure you already have, I think that focusing on improving power output by adding in different nutritional resources for the bacteria is also a perfectly good option.

In regards to your question about the galvanic cell, I think both the galvanic cell and the microbial fuel cell operate using the same mechanism. They’re both electrochemical cells that produce energy through oxidation-reduction reactions. The only difference is that the electrons in the galvanic cell come from metals and the electrons in the microbial fuel cell come from bacteria. So, I would say the microbial fuel cell used in this project is basically just a modified version of the galvanic cell.

I hope this helps! Feel free to ask any more questions that you have.
Katelyn

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Sun Dec 06, 2020 12:33 pm

Hi,

I checked out the website link and it was very helpful, so thank you for that. I have narrowed my decisions to two options, but I am not sure which one would be more effective, so I was hoping if you could help me with that.

My first option is to build four microbial fuel cells. In three of them, I will be feeding the bacteria with different amounts of yeast extract and try to optimize which amount is the best. The fourth cell will simply be a constant to compare my results. My second option is to again build four microbial fuel cells, and in three of them, instead of yeast extract, I will add natural compost as a source of nitrate in different amounts and attempt to optimize which quantity brings the best results. And like the other choice, the fourth cell will be a constant.

Because I do not have much background on how yeast extract and nitrate will affect the cellular respiration of anaerobic bacteria I was wondering if you could guide me with this decision. Thank you so much!

Brindha

koneill18
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby koneill18 » Mon Dec 07, 2020 12:23 pm

Hi Brindha,

I think those are both great options! I would personally go with the natural compost option because there is a lot of good evidence to support the hypothesis that feeding the bacteria with compost will improve the power output in the fuel cell. There isn't as much information out there on the yeast extract, so I'm not as certain about that one. It could definitely still work, but I'm not sure it will work as well as the compost.

Katelyn

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Thu Dec 17, 2020 1:42 pm

Hello,

I think I will go with your recommendation, the nitrate, since it is very easy to obtain. I was wondering if you possibly had any websites or sources where I could find more information about how nitrate can help feed bacteria. Thank you!

Brindha

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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby koneill18 » Thu Dec 17, 2020 6:36 pm

Hi Brindha,

Here are two articles that talk about how bacteria use nitrates to generate energy:
https://bio.libretexts.org/Bookshelves/Microbiology/Book%3A_Microbiology_(Boundless)/5%3A_Microbial_Metabolism/5.09%3A_Anaerobic_Respiration/5.9B%3A_Nitrate_Reduction_and_Denitrification

https://courses.lumenlearning.com/bound ... spiration/

This is a research paper where the researchers used nitrate as an oxidant in the cathode chamber of a microbial fuel cell:
https://link.springer.com/article/10.10 ... 010-9148-0

And here's another research paper talking about how compost can be used to power microbial fuel cells:
https://www.mdpi.com/2071-1050/7/9/12634/htm

I hope these are helpful!
Katelyn

brindhaaa
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Re: Finding a Bacteria for my Microbial Fuel Cell

Postby brindhaaa » Thu Dec 17, 2020 9:55 pm

Thank you so much! I will look into those right away!


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