MFC isolate culture - ideas for media?

[Nathan McCorkle]

Portland-folk are taking-apart the mud batteries we made a few months
ago, and we're thinking we'll take a culture. First idea for media is
PDA (potato dextrose agar).

I'm searching for papers now...

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-Nathan

[Cathal Garvey (Android)]

Be sure to use candle jars for some plates, many of the interesting bugs will be anaerobes. In fact, a DIY glovebox made fairly anoxic would be a good idea for actually dismantling it in the first place, some anaerobes are highly sensitive, die in minutes on exposure.

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Sent from my Android phone with K-9 Mail. Please excuse my brevity.

[Patrik D'haeseleer]

Agree with Cathal - the most interesting biology will be at the anaerobic anode side of the MFC.

I was working with MFCs a couple years back, and have an idea for isolating electrogenic bacteria that I've never had a opportunity to try out yet. Essentially, you'd build an MFC layer cake inside a Petri dish with a transparent electrode on the bottom (e.g. ITO coating inside a glass Petri dish). Streak bacteria under anaerobic atmosphere onto a slab of agar, and put that slab *bacteria down* on the bottom electrode. Cover the slab with a proton exchange membrane and air cathode. Seal the sides of your layer cake with vaseline to avoid air leaking down to the bacteria.

The idea is that you would be selecting for colonies of bacteria at the bottom of the Petri dish that can oxidize the carbon source in the agar, using the bottom electrode as electron acceptor. You can either short circuit the anode and cathode, or even slightly forward-bias them to pull electrons out of the bacteria (but not so much that you get electrolysis, obviously).

Patrik

PS: have a look at Genspace's anaerobic glove box instructable! http://www.instructables.com/id/DIY-Anaerobic-Chamber-aka-glove-box/

[Dakota Hamill]

Candle jar probably a good idea for a cheap oxygen free environment, though I"ve never done one.   A sweet nitrogen flooded make-shift growth chamber would be nice to, and nitrogen is really cheap from any gas supply company.  PDA I use mainly for fungal culture though I have had bacteria grow on it, specifically actinomyces.  PDA is usually pH adjusted to 4-5 to inhibit bacterial growth so check on that or maybe try a bacterial selective media as well.

There is a really cool jar that I forget the name of that is basically just a pile of mud from the bottom of a lake you sit in a 2 ft tall glass or plastic jar and you can visualize the different bacterial growth types (anaerobic vs aerobic, faculative vs obligate etc) and sometimes see color based on weather or not they use iron.  I've been googling all possible word combinations but I can't find it!!! It's named after a specific dude.

[Nathan McCorkle]

winogradsky is his name i believe

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-Nathan

[Patrik D'haeseleer]

Yep - we made a bunch of Winogradsky columns for the BioCurious Makerfaire booth two years ago. I stuck a wire in the top and one in the bottom, to show that it works as an MFC as well. Think I got something like 42 mV open circuit.

Here's a nice closeup of the Winogradsky column I made:

http://www.meetup.com/BioCurious/photos/3342772/55566962/

You can make one of these in a 2L soda bottle, and stick a syringe through the wall of the bottle to sample the bacteria growing at different spots.

Patrik