Science Buddies: "Ask an Expert"

Hi I'm doing a science fair project on a microbial fuel cell and was wondering if I tested out yeast, how would I put it in the anode and what materials would I need to obtain and activate the yeast, while not allowing it to go through fermentation, but cellular or anaerobic respiration for it to produce energy?

Hi Vana,

This is a great project and very challenging project from the Science Buddies website! It requires expertise in engineering and knowledge about electrical circuits and microbial metabolism. I think you are planning to do a variation on this project:

https://www.sciencebuddies.org/science- ... p026.shtml

You obviously understand the basic principle of the microbial fuel cell; the microorganism must be growing anaerobically and must transfer the electrons produced from energy metabolism to an electron acceptor other than oxygen. Yeast that are growing anaerobically will be able to this.

Here is a paper that describes a microbial fuel cell with yeast. The authors used methylene blue in the anaerobic anode compartment and potassium ferricyanide and methylene blue as electron acceptors in the aerobic cathode compartment. The authors used glucose as a carbon source, but you might find it easier to use sucrose (table sugar).

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2635613/

In the original project idea, the benthic mud sample is used as a source of mixed anaerobic bacteria; if you use yeast, you don't need to use mud. If you add mud and yeast, you would have a mixed culture. So, if you want to do a study with yeast, then you would want to start with a sterile culture medium, and just add the yeast. If you don't aerate the anode compartment, the environment will rapidly become anaerobic as the yeast start to grow.

The microbiology techniques and troubleshooting guide on this website should be helpful to you.

https://www.sciencebuddies.org/science- ... ques.shtml

Please post again if you have any questions.

Donna Hardy

Hi,
I was wondering if i should just make it into bread dough and just put it in the anode? If so, how long can it last?

the bread dough will last up to three days without any sign of decay

Hi Vana,

I apologize for not responding earlier to your last inquiry. Did you do the experiment with bread dough? I thought it was a very original and interesting idea to try. How did it work?

Donna Hardy