Zero to Genetic Engineering Hero - Chapter 3 - Growing E. coli Cells 64
After incubation, verify that the bacteria paint has changed color before starting this step. If it is not yet
colorful, incubate longer or refer to the manufacturer’s instruction manual. The colors develop best at
37˚C. If you are using a DIY incubator where the temperature is not 37˚C or very close to it, your colors may
not develop fully - they will stay in shades of pastel. You can use them as pastels paint.
Take two LB agar Petri dishes (from Step 1) out of the refrigerator. For each petri dish:
Draw your own design on one of the blank stencils. Place one of your unused LB agar plate on top of your
stencil or the pre-made image stencil. Simple images without many details work best for the rst time!
Take your petri dish streaked with colorful bacteria from your incubator. This is your painting palette. Using
your ‘bacteria paintbrushes’, dip one into the paint on your painting palette. Paint your art by carefully
streaking across the surface of the LB agar of your new plate, following your image stencil. When doing bioart,
it is okay to dip your painting instrument into the bacteria more than once, but since you will be making
more painting s on remaining petri dish(es) keep some paint and paintbrushes for later.
Remember to verify that your bacteria paintbrush touched the paint. After you have painted your image on the
agar, you should be able to see some evidence of your work as a ‘wet’ trace if you hold the petri dish in the light.
The individual bacteria themselves are too small to see and require time to grow for you to verify success. Paint-
ing with bacteria is hard because it is like painting with invisible ink that appears days later!
3. You can choose to paint another agar plate right away or save it for later. After you are done painting for the
day, put used items like loops and cotton swabs in the inactivation bag. Close your painting palette petri dish
and place it in a resealable bag (You can use the same one that has the unused agar petri dishes). Place it,
along with the remaining unused petri dish, and bacteria paintbrushes in your lab refrigerator or in a sealed
container that goes in the refrigerator (Chapter 2). You will incubate your painted plate(s) in the next step.
Step 11. Incubating E. coli cells
Once again, you will be incubating petri dishes. This time, you will incubate your painted petri dish. Turn on
the Incubator of your Minilab to 37˚C. As the incubator heats up, you should ip your LB agar plates so that the
bottom is up and the lid is down. Following the manufacturer’s instructions, place the ipped LB agar plates
with E. coli bacteria onto the paddle, cover with the humidity chamber, then place into the incubator. Turn on
the timer to better monitor growth.
Incubate the petri dishes for ~24-48 hours. You will start to see growth after ~12 hours, and the bacteria will
start to change color shortly after.
Step 12. Viewing & Preserving your bioart with a Keep-it Kit
Figure 3-11. Left: Bioart made with uorescent bacteria by Nathan Shaner, photo by Paul Steinbach. Created in Nobel laureate Roger
Tsien’s lab. Right: Bunny bioart made with Amino Labs’ Canvas kit under black light and natural light.
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