brindhaaa
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Help With Microbial Fuel Cell

Postby brindhaaa » Mon Oct 25, 2021 6:33 pm

Hello there!

My name is Brindha and I am a sophomore high school student. I am enrolled in my school's science research program and am thinking of an idea for my project. I won at my city science fair last year, but this year I really want to do a complex project and try to make it to the County or Regional fair

Last year I worked with microbial fuel cells. I tested the effect of nitrogen on the efficiency of MFC's by adding different concentrations of coffee grounds to the MFC's. Working with MFC's really interested me in that field, and I have decided that this year I would also like the work with MFCs. I looked at the ScienceBuddies Microbial Fuel Cell page and read through it. I believe I have a good understanding of how MFCs work. The problem is, I don't know what I want to do! If someone could please help me think of what to do, and possibly guide me throughout the way, that would be really amazing!

Btw, my pre-approval is due Nov 5, so I need to have a basic idea of all my procedures laid out before then.

Thank you so much!
Brindha

Moderator removed personal identifiers, per Science Buddies policies.

17eugenekim
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Re: Help With Microbial Fuel Cell

Postby 17eugenekim » Wed Oct 27, 2021 6:00 am

Hi Brindha,

Welcome back to Science Buddies! It's great to hear that you've developed an interest in expanding on your science fair project. Let's see what we can do before your deadline.

The first thing I'm going to link is our Project Guide overview: https://www.sciencebuddies.org/science- ... ience-fair. This might be old news for you, but I always like to start by making sure students understand the basics of building and conducting an experiment for a project. Be sure to at least look through all the pages in the first tab, and then browse through some of the relevant sections of the Advanced Project Guide tab, as they may also be useful to you.

Which Microbial Fuel Cells pages have you seen from Science Buddies so far? It looks like there's a few, which might help kickstart your ideas (see top 4): https://www.sciencebuddies.org/science- ... fuel+cells

Ultimately, however, the project idea should come from some question you are interested in answering. What is it about MFCs that you want to answer? Based on what you understand about how MFCs work, how do you think they can be "improved" or "optimized"? For instance, last year, you said you tested the importance of nitrogen content in MFC efficacy. Are there other variables that you want to try and tweak? Perhaps something about the type of medium the microbes grow on, or something about aerobic vs anaerobic bacteria? Just throwing out ideas. Get creative, and remember we're thinking about the scientific question itself -- we'll worry about details of experimental procedure later (but it's of course helpful if you think about both at the same time, too!).

Best of luck -- keep us posted in this thread!

brindhaaa
Posts: 44
Joined: Mon Nov 02, 2020 10:36 pm
Occupation: Student

Re: Help With Microbial Fuel Cell

Postby brindhaaa » Mon Nov 01, 2021 5:16 pm

Hey there!

Thank you so much for getting back to me, it means so much!

I looked at those links you threaded and I have read through both of them. Thank you for that!

Also, getting back to your "how do you think they can be improved" or optimized" question, I think this year I am going to add different concentrations of a specific enzyme to catalyze the anaerobic respiration level/speed. I researched a bit about which enzymes are involved in the overall process, and the two most important ones I found were pyruvate decarboxylase and lactate dehydrogenase. Do you have any feedback on this idea to add either of these enzymes to my experiment? I would love to hear anything you have!

Thank you so much for your help
Brindha

17eugenekim
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Re: Help With Microbial Fuel Cell

Postby 17eugenekim » Tue Nov 02, 2021 2:32 pm

Hi Brindha,

Glad to be of some help.

It sounds like you're heading in the right direction with these questions! Enzymes are certainly a variable you could test, and the ones you've listed (pyruvate decarboxylase / lactate dehydrogenase) are the critical ones that are used in anaerobic metabolism.

Now, it's probably not feasible to measure out concentrations of enzyme and dump it into the MFC build. You'd have to get your hands on some kind of extract or purified mix of the enzyme you want, and that may be a logistical obstacle if you're not doing research in a lab. It's probably pretty pricey that way, too.

However, while purified pyruvate decarboxylase might be hard to get, live yeast is much easier -- home bakers & brewers use it so you can get it from a lot of retailers. Live yeast (Saccharomyces cerevisiae) uses pyruvate decarboxylase to ferment glucose into ethanol. If you go this route, you should read up more on yeast and pyruvate decarboxylase, and fermentation as well. I found this source on yeast as an additive in MFCs: https://www.intechopen.com/chapters/56779

Where do you plan on getting the microbes for your MFC? I think the types of microbes involved in the design can also affect the relationship between enzyme activity and metabolic rate. Just a side thought.

Lastly, I want to highlight a secondary variable that may be of interest to you. Enzymes are protein machines that function best at an "optimal temperature" -- which in a majority of cases is about 37 C. If they get too cold, they can be significantly less effective or just stop working entirely. If they get too hot, they can undergo denaturation, breaking down and also not working. I don't know what the exact temperature parameters are for these enzymes, but if you can get access to an incubator or have another way of maintaining various stable temperatures, I think this might be a worthwhile experiment to test out. Up to you.

Hope that helps!

-Eugene

brindhaaa
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Joined: Mon Nov 02, 2020 10:36 pm
Occupation: Student

Re: Help With Microbial Fuel Cell

Postby brindhaaa » Tue Nov 02, 2021 7:49 pm

Hey,

I think you are right, as those two enzymes would be very hard to gain access to outside of a lab. Also, I took a look at the link about adding yeast to an MFC. I love that idea! However, I was researching a bit more about that and it looks like there is already a lot of experiments and studies supporting the effect of yeast on an MFC. Are you aware of any other enzymes involved in anaerobic respiration that are reasonably easy to access? I have been researching a lot recently but unfortunately, I haven't come across anything I can use : (

Last year, I obtained a benthic mud sample from a lake in my city. I got great results with it, and I plan to get my microbe sample from there this year as well.

Also, regarding the idea of testing temperature as a variable, that's a good idea, however, I am trying to find something a little more complex to test. But that is a very important factor to keep in mind. I think I might borrow an incubator from a teacher's lab or purchase one to ensure that the MFCs are in the same condition.

Thank you so much,
Brindha

17eugenekim
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Re: Help With Microbial Fuel Cell

Postby 17eugenekim » Thu Nov 04, 2021 5:55 am

Hi Brindha,

I don't want you to get too discouraged by an abundance of existing research on similar topics as an idea that you want to do, because that does tend to happen at the level of a lot of high school science fairs. That said, I understand your concern. This is actually partly the reason why I brought up temperature as a secondary variable. I wonder if you could integrate yeast AND temperature to conduct a more complex series of experiments.

If that's still too simple for your tastes, we can look for alternatives. I'm not entirely sure how to add lactate dehydrogenase in a controlled way. However, I do think we can increase production rate of lactate, the reactant in the lactate dehydrogenase reaction. Lactobacillus bacteria, particularly Lactobacillus acidophilus, is a commonly found probiotic that conducts lactic acid fermentation. You can find probiotic capsules with live bacteria in some grocery stores in the health & wellness section, which should be nice for experiments. I wonder if you could even use yogurt, as long as it says it has "live cultures" -- which would be cheaper & a bit more intriguing, but also I'm not sure how much I trust yogurt companies' claims.

Maybe reading up on fermentation will give you more ideas. At the moment, though, in terms of conducting enzyme-based experiments using commercially available tools, I think those are your best bets -- probiotics and yeast. Of course I'll let you know if I think of anything else.

Hope that helps.

-Eugene


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