We’ve been growing stuff during the Biohacking Thursday at the biolab last week.

We made some agar plates from an ancient minimal media mix (yeast extract + salt + agar; expired in 1986, but still works like a charm!) and adding some tryptone (peptides - food for bacteria). Here’s the recipe (for 1l of media):

  • 12 g of minimal agar media mix (we used 5 g to make 400 ml)
  • 10 g of tryptone (we used 4 g to make 400 ml)
  • 1 l distilled water (we used 400 ml)

We weighed & added the right amount to make 400 ml of media, and mixed with distilled water in a 500 ml glass bottle. We then put that & cleaned glass Petri dishes into the autoclave (it was an excuse to unpack & turn it on again!) and left it to do it’s sterilization work at 121 °C for 40 minutes or so.

After the media was done cooking, we poured it (carefully! super hot) into the sterilized Petri dishes (also hot!). As this wasn’t a precision experiment, and our laminar hood is still out of order, we did so right on the table top. (Which we later swabbed & tested for bacteria too…)

When we were done, we took the plates out to the balcony to cool down, as we were anxious to start swabbing & seeding those plates with some bacteria!!

We swabbed very interesting places from around the biolab & ourselves, including the tabletop, our smartphones, put our fingers & our chewing gum on the plates, two guys swabbed their belly buttons, and we all took our saliva samples & plated them on one plate (divided in sections). We then grew the cultures in an incubator at 37 °C (although that might have been somewhat inaccurate since it was the first time we used it after the move) for 3 days (as we forgot to take them out sooner, ouch!).

Here’s what grew:

^ Yikes, some mold got in there too! But look at all those lovely colonies growing around the gum 💚

^ Bellybutton samples were the most powerful 😱 as lot’s of stuff (rather smelly actually 😳) grew

^ Looks like nothing at all, but could be so much stuff that you can no longer see individual colonies!

^ Loads of bacteria (but no distinct colonies) here. That’s what happens when you add too much in the “seed” sample!

^ Our joint saliva sample 💚 some people have more bugs in their mouths than others! Look at the diversity too!

^ The most versatile bacteria were found on fingers. See at least 4 or more types of colonies with different shapes & colors (morphologies)? Those are all different bacteria!

We can’t do much to identify the species of bacteria we got on all these samples at the moment, unless we do some molecular biology hocus pocus or play with differential media. Which we might do soon!


Another Biohacking Thursday coming up this week - we’ll be talking about & playing with different kind of bugs - beetles ;) come along, Thursday 19:00 @ Technarium.