Picture of Lime Jello, Yeast and Carbon Paper Fuel Cell
Can Jello Brand Instant Gelatin replace coal fired power plants? Probably not but it can be used to build a demonstration microbial fuel cell from common materials. This is a fun classroom or rainy day project, tie multiple cells together and use the power to light an LED. You'll probably need a joule thief as well. Output voltage and current are a function of cell volume and carbon electrode size.

Here's how it works, we're going to mix a little Jello brand Instant Gelatin with some Fleischmann's Active Yeast and a few drops of plant food. Once that solidifies we're going to cut out some fun Jello squares (yes, they still jiggle) and, using the carbon paper as electrodes, we're going to tap the energy produced by the yeast to create electricity.

This is an innovative form of the popular single cell microbial fuel cell or MFC. The gelatin serves a variety of useful purposes, including MFC container, fuel source and electrolyte. The yeast will feed primarily off of the sugar in the gelatin mix while the gelatin seals out ambient oxygen.

As you can see we started off with about 500 mV which ain't bad for some Jello and yeast...

Now let's get started!
Remove these adsRemove these ads by Signing Up
1-40 of 102Next »
sorry still no link.
meekah5 years ago
 is there any way we could connect several of this MFC's to produce energy that could light a small bulb?
egbertfitzwilly (author)  meekah5 years ago
Absolutely, mkhabir ( ) has 30 LEDs running off an array he uses to light his room, as I recall it was approximately 10 gallons or so.

The optimum configuration would be use an array of MFCs to feed a battery charger and use the recharged batteries to drive the light. The MFC generate power continuously at low levels, by using a rechargebable battery you can "compress" the stored power to a usable voltage.

You can construct an easy test bed using one of those solar powered yard lights. Simply remove the top and clip the leads to the solar panel then attach the leads from your MFC array.

Check out my for information on wiring the array.
that link u posted . it not there any more!!!
egbertfitzwilly (author)  astral_mage1 year ago
His link is in the next response in this list.

Newly, i also incorporated an solar panel to run the pumps and installed an Lithium Mobile battery charger to charge your phone from ALGAE?!
gizander5 years ago
Hey there...
Thanks for your instructibles. I've only recently gotten into Bioelectricity and didn't realize harvesting it could be done so simply and easily...
Besides the green jello looking the part I think that the lime flavoring (probably citric or ascorbic acid) served as your electrolyte. You didn't mention adding salt or any other electrolyte to the medium so did you luck out there or do the trace minerals which are there to feed the yeast serve a double purpose as ions? ... just wondering what conducts in the solid medium...
BTW, here in the Philippines they still sell reams of carbon paper at office supply stores. I'm not sure what it costs now but maybe it would be cheaper than ordering from a specialty online supplier. Several reams through surface mail shouldn't cost that much if you plan to make a jello fuel cell battery to power your
I thought about using CP for electrode material some years back but I thought the greasy binder would render it non conductive and wasn't going to buy a whole ream just to find out it was an insulator or had 1 megaohm resistance...haha
In my electrochemistry work I use carbon cloth. Suppliers from China will give you a first time free sample of several square feet (and theirs is *Activated* carbon cloth...). I actually make standard carbonized fabric in the lab by heating denim or felt, etc. in the absence of oxygen...This gives a much greater surface area which will boost your Amps tremendously (and for an immobile fuel cell like your double tee junction pipe one, the CC's structural duradility should be adequate). Well, this is becoming an essay...more comments on other posts...Thanks again and Keep working for the Cause!

egbertfitzwilly (author)  gizander5 years ago
I just lucked out. Now that you point it out I have no idea what the mechanism for ion transport is in this. Could be as simple as the coloring in the gelatin which would be extremely efficient at gathering stray bits. Can you provide a URL for the Chinese folks? Many of the research papers talk about carbon cloth but I haven't found a ready supplier. I can make biochar in my BBQ but hadn't considered cloth. Hmmm, could be an instructable in the works. I was very intrigued by the electron microscope carbon mesh. It seems a very convenient porous carbon electron that could be exploited easily. Plus the carbon is bonded directly to the electron collector grid, it doesn't get much better than that.
dude u really need to go check out they will have it all.
As far as I know the ionic transport wouldn't be the food coloring. If I had to put money on it I'd say it was citric or ascorbic acid used to make the lime jello sour; however, the green dye used may be a facilitator which shuttles electrons from the microbes to the anode. Older microbial fuel cells used things like methyl blue and other compounds (used to stain histological samples in Biology so they were visible under the microscope) as facilitators. The newer ones just use microbes that don't need a facilitating agent (since most are very toxic and are considered pollutants). Since I don't think yeast cells (which you used) have the pili required to transport electrons w/o a facilitator you may just have stumbled upon a "green" (no pun intended) facilitator.
My Organic Chemistry is pretty bad but I can say that if either of the two acids was serving as the electroluyte (and I can't imagine anything else in your cell that could have been) their ionic form in "jello solution" were your electrolyte ion transport molecules. More interesting to me is the green dye and if it is indeed a facilitator that is non-toxic. In any case, you can confirm if the lime flavor was the electrolyte by using jello without any flavoring (or any ionic compounds) or by using agar that is non-conductive as well. If your plain jello/agar cell gives almost no power you'll know it was an ingreduient in the lime jello. Try adding salt to both your lime cell and the plain one. the lime one may get a power boost and I'm sure the salt in the plain one will make it work (since it now has an electrolyte).
I've just gone through a reformat so I don't have a URL for you but all the companies I ordered from do business on A search there or on Google for activated carbon cloth will yield many companies that will ship a free sample. I didn't pay for the shipping because I pulled out the "poor" card--as well as saying that I will be ordering huge amounts if their stuff lived up to their claimed specs. (Both my negotiation tactics are true, BTW...) But since you know how to make carbonized materials (wouldn't do it in your barbie though--chemicals and all in food...etc...) I wouldn't bother even paying for the shipping. They claim over 1000 square meters surface area per gram for the 3mm stuff I got--I just didn't see it act like that in the lab though; it also has bad conductivity unless compressed. Now that I know that my own carbon cloth works just as well and that carbon paper works too I'm shifting to those as electrodes.
You mentioned electron microscope carbon mesh. I haven't come across that. From which instructable was it? If it's doped with electrocatalysts that would make it even better!

Just a note from a self-taught baker... salt kills yeast!

egbertfitzwilly (author)  gizander5 years ago
I found the electron microscope stuff googling 'carbon mesh'
can i use carbon cloth instead of carbon paper? also, do you think this would suffice as a dumbed down version of a microbial fuel cell with containers as the anode and cathode, a salt bridge and the whole mile? SCIENCE FAIR IN 2 DAYS HELP PLEASE!!!!!!
(removed by author or community request)
egbertfitzwilly (author)  dstrater2 years ago
I have gotten reasonable results using carbon filters from aquarium pumps.

You can probably verify the carbon paper with a conductivity test. There should be appromixately 0 resistance across the surface on the transfer side.

Also the more holes you punch in the top, the greater the efficiency. This is a function of available oxygen and can be used in a bell jar to show power levels dropping as a candle burns the oxygen ( for instance ).
We made our own carbon paper using plain white paper and bought some artist's carbon for drawing and just scribbled very thickly onto the paper. It worked! We got measurements of up to .22 mV. We are attempting it again today to see if we can get higher measurements.

I still can't figure out what the mediator is in this project that is actually making it work. I was wrong about the fluoride in the water, that would actually make it work less if it had any effect at all. NaF prevents glycolysis. We tried this with plain gelatin with sugar added too, calculating the measurements of sugar in green gelatin, and an approximation of about 4g per tsp of sugar, so we added 20g of sugar to 1 cup of clear gelatin. We got some slight readings out of the plain gelatin, but it was much lower than the green. (.01 and .04 mV compared to .22 and .21 mV). So clearly something in the green is making it function better.

The first time we did it, we also added too much yeast (thinking more yeast would produce more electricity), but it just got all puffy and didn't produce anything, probably processed all of the sugar before we even got to measuring it.
try using char cloth. theres aplenty of instructable on that subject alone
egbertfitzwilly (author)  dstrater2 years ago
That is an outstanding innovation. You could probably also use a #2 pencil. One gating factor is the amount of oxygen available at the surface electrode.

You can briefly demonstrate this by blowing softly on the surface electrode, you should corresponding variances in current. It is not impossible that the current could also be improved by wetting the surface electrode with a saturated sugar solution.

This will increase the availability of dissolved oxygen at the surface electrode and should increase current. The actual voltage is generated biologically by the yeast. This was first noticed in the 70's and subsequent research has varied. Visit for more information.

The sugar in the jello acts both as food for the growing yeast colony as well as providing the necessary electron bridge between the electrodes. I have also noticed the difference in the gelatins, I suspect the dye+sugar is more conductive.

I believe it would make an outstanding instructable if you were to do a well controlled test and measure the difference between the two media and document your results. That could also inspire other science fair projects.
try using charcloth in place of yr carbon paper
I hope you got the science fair sorted out, I don't check my email on Instructables daily. Yes, carbon cloth would work instead of carbon paper. I wouldn't call it a dumbed down version of an MFC, I would call it an innovative design for a self consuming MFC that doesn't require external packaging.
ezhilabhi1 year ago
can any culture medium be used?
spiderfurby5 years ago
Would a carbon rod do - for example the carbon rods out of large "D"cells, or the carbon rod used for arc gouging? OR is there a Mcgyver way of making your own carbon paper? Maybe. I am thinking survivalist type ideas where u only have the minimum resources.
egbertfitzwilly (author)  spiderfurby5 years ago
Yes a carbon rod, activated charcoal or raw charcoal can also be used.

In this instructable step 4 starts with: Now Macgyver

A DC motor brush from the local hardware store or power tool can also be used:
Thanks for your reply - I will investigate the alternatives - I am doing this for my son (10 years old) to give him an appreciation to the fact there is more ways of generating electricity than by coal or oil. The salt - idea is brilliant as well. I am from Victoria, Australia. We are in dire straits with regards to low rain fall and our water dams are disappearing quicker than we can replenish them. The government has come up with a brilliant idea of a desalination plant to turn sea water into drinkable water. But they are myopic with regards to the waste by product salt and are going to pump the concentrate back out to sea. This not very good for the sea life. But they instead my opinion they could of harnessed the salt energy to provide power for both the plant and possibly other townships. We have lots and lot of sun shine. By harnessing the sun and turning it in to a concentrated solar condenser they could crate salt baths and turn them into molten salt. Which in turn can then be used to provide heat to power steam generators - using again salt water. But no we rather pump it out to sea.  Why I have no idea.
We are also using  a method of under ground control burning of coal gas to produce energy for steam. Do you know how that works. It is an alternative to open cut mining. They use sea water to provide steam as well.
egbertfitzwilly (author)  spiderfurby5 years ago
Actually it doesn't have to be that complex if supplies of aluminum feedstock are available. The concentrate can be electrolyzed into sodium hydroxide using power derived from microbial fuel cells based on the local municipal wastewater treatment facility. Using the sodium hydroxide as the electrolyte in an aluminum oxide fuel cell will produce clean cheap power far more reliably than solar. The aluminum can be recovered and reprocessed to create a sustainable energy cycle.

If you are in a position to submit a proposal I would be very interested in discussing this in more detail.
where do you get the energy to reprocess?
where do you get the energy to reprocess?
I saw an article which I have been searching in-vane for on the internet without success with regards to Norway providing Britain with large power station shipping tankers  that utilize aluminum and some other process to produce electricity. The tankers plug directly into the power grid and are capable of delivering power for 5 years. Once the Aluminum is oxidized it is sent back to Norway and is treated (some how to revitalize it) and also topped up with new aluminum then sent back. I just can not find the article any more.   I thought that this was innovative.
egbertfitzwilly (author)  spiderfurby5 years ago
Its certainly possible. High capacity aluminum oxide batteries are available as commodity products. They are used in emergency power backup systems for the US PSTN among other things. There is no significant reason they could not be used ship board to drive electric motors.

The US DOE has selected the al-air battery as the primary candidate to replace the internal combustion engine for range, weight and compatability with the existing fuel infrastructure ( electrolyte replenishment ).

The configuration you outline may very well be cost, weight and range compatbile with a diesel electric system once a reason to invest in initial development such a system exists.
Geepers, why not suggest that the desalinization plant reject brine be fed to a plant extracting magnesium and bromine from sea water. Its already concentrated and then run the brine into a chlorine bleach plant.
 wait, for charcoal, you would insert one piece entirely into the Jell-O and one piece half into the Jell-O right?
I would put one piece under the jello and lay the other on top to get maximum surface area. I'm not sure how well the rods will work, I think you'll get power but I can't speak to its efficiency.

If you're talking about ordinary charcoal briquets I'd grind them up and use a layer of charcoal under the jello and a second layer on top.
 Aight, thanks, but i don't think that i understand what determines which electrode is positive and which one is negative. Is it that one is maybe exposed to air while the other isn't? 
That is correct. There is a detailed discussion of the exact mechanism on wikipedia:

I think that sprinkling fine charcoal powder on a sheet of paper saturated with salt water and then putting a heavy book on top would do it. (Though you'd have to wait for it to dry.)
dbell2 years ago
I was going to ask about how the heck this was polarized, but found your reply and link.

Since the air-exposed surface is an important active element, wouldn't a thinner layer of jello between much larger electrodes provide more energy, for the same volume? This would both increase the exposed surface area and reduce the bulk conduction path length.

suy23 years ago
what proportions did you use for this? i tried doing this but my gelatine gets all puffy as the yeast grows
egbertfitzwilly (author)  suy23 years ago
The gelatin is supposed to break down, it is consumed by the yeast colony.
oh.. and uhm i tried making four units of gelatine battery which read 2V. i was trying to make a toy car function which only needs 1.5V to run but it won't function :|
egbertfitzwilly (author)  suy23 years ago
It is highly unlikely that you can power a vehicle of any sort with this. You simply can't get enough current. The best you can do is trickle charge the batteries that run the car.
1-40 of 102Next »