Science Buddies: "Ask an Expert"

Hi,
My name is Jackie Ni and my project is "Power production between mixed inoculums of bacteria vs pure inoculums of bacteria." I have constructed the microbial fuel cell but haven't purchased the bacteria yet. Could someone tell me where I could purchase bacteria to use for the microbial fuel cell such as Shewanella putrefactions and geobacter metallireducens. Could you also help me with the process of testing of the bacteria. I don't know if I should use wastewater for the bacteria to consume or a glucose and yeast combination. And could someone tell me how to inoculate anaerobic bacteria into the anode of a microbial fuel cell. Thank you guys so much!

From,
Jackie Ni

Hi Jackie,

You have chosen a pretty ambitious but very interesting project.

I would make one suggestion for you to think about. You said you plan to compare single bacterial cultures to mixed cultures. My first thought when I read that was why don't you compare the artificial mud cultures to natural mud cultures. I understand that you will not know what bacteria are in the mud obtained from a pond but chances are very good that they include the two species you listed. You could test the pure cultures separately and together, but I would also do a natural mud test for comparison.

As to where you can get pure cultures of Shewanella putrefaciens and Geobacter metallireducens, the American Type Culture Collection (ATCC) is the usual source: http://www.atcc.org/Products/Cells%20an ... teria.aspx

The ATCC can be quite expensive, however, and it might be worth it for you to call tech support at Carolina Biologicals (http://www.carolina.com/?s_cid=ppc_gl_c ... Aj6f8P8HAQ#) and ask them if they sell these bacteria or know of a less expensive provider.

If you look up the bacteria on the ATCC website, there are instructions for how to grow them. There is also some information on the web:
https://en.wikipedia.org/wiki/Shewanella_putrefaciens
https://en.wikipedia.org/wiki/Geobacter_metallireducens

Are you planning on using sterile dirt and distilled water to make a mud for your bacteria? Remember that these are anaerobic bacteria and need to be away from oxygen in order to function in the microbial fuel cell. You have to mimic these conditions with your artificial mud cultures. I'm not sure how to do that except by mixing water and dirt and then adding your bacteria to the layer that is right next to the electrode and filling it up the rest of the way with mud. You will probably have to do a couple of test runs with different amounts of bacteria and maybe some nutrients to get the artificial mud to generate electricity.

Scientific experiments are much more fun when you don't know what will happen, so don't get discouraged if it doesn't work the way you want at first. Keep GOOD notes of what you do and what happens and take lots of photos.

Let us know if you have more questions and we'll try to guide you.

Good luck!

Sybee

Ok thank you so much!

You are welcome, Jackie!

Please keep ALL your posts in this thread so the experts can see all of them without having to hunt through the list of posts. It makes it much easier for us.

Thanks,

Sybee