Re: [DIYbio] First DIYbio project

On Sun, Dec 7, 2014 at 8:35 PM, Rome Robinson <rxxpredator@gmail.com> wrote:
>
>
> Hello. What would diybio project would you recommend to a Junior in high
> school who has an interest in biomedical engineering and computer science?
> This would be my first diy bio project by the way.

Here is an achievable goal:
learn sterile technique

What you need:
agar-agar from Asian food store (~$1.50)
half-pint straight-walled canning jars ($12 for 12 jars)
pint straight-walled canning jars ($12 for 12 jars)
straight razor blade (pack of 100 ~$10)
70% alcohol ($2)
toothpicks (~$2)
metal tweezers ($5)
reverse-action metal tweezers ($5-10)
chunk of oyster mushroom from grocery store bulk section ($0.25 - $2.00)
pressure cooker ($10 - $40)
alcohol burner ($5)
bag of potatoes ($2)
dextrose/glucose ($4)
paper towels ($3)
nitrile gloves 50-pack ($10)
total cost $83.75 - $119.50

brief overview, vague enough to get you to think critically (I hope):
look up agar recipes that use potato and dextrose
whip up some agar mixture, then sterilize in pressure cooker in pint
jar (flip the lid so no vacuum is created upon cooling)
in a separate jar sterilize some toothpicks, and in yet another the
tweezers (and you could do some razors too)
sterilize a few jars with a ~200mL water in each
sterilize several half-pint jars empty (rinse them with water after
purchasing, since there will be unknown factory manufacturing residue)
(with lids flipped)

after sterilization of the jars, let everything cool on it's own
before opening the pressure cooker, this will take at least an hour or
two

when the temp reaches 'warm enough to touch comfortably', open the
pressure cooker
remove the agar mixture, swirl it to make sure it's well mixed
carefully pour some of this mixture into each of the dry sterile
half-pint jars, then cover them again (with flipped lids)
let agar cool to set firmly

light your alcohol burner in a room with very very calm airflow (i.e.
a small closet or closed room)
put on gloves
wipe the mushroom exterior with an alcohol soaked paper towel
use the reverse-action tweezers to hold the razor, then
flame-sterilize the razor
cut in a single slicing action a layer from one side of the mushroom chunk
flame-sterilize the razor
cut another layer from the mushroom, but on a different face (think
about how a sawmill processes a round tree into boards)
flame-sterilize
cut another layer from a different face
flame-sterilize
(I hope you get the point, which is to use a sterile instrument to
remove non-sterile tissue, since this was exposed to microorganisms
during shipping, at the store, etc)
once you have a nice sterile 'stub', flame-sterilize the razor again,
and finally open a cooled agar jar, and slice a layer of the 'stub'
then place it on the agar surface, close the jar with the lid
(flipped)

repeat for as many jars as you prepared, then place in a cabinet in
your kitchen or somewhere reasonably warm (not the cold uninsulated
garage, but also not somewhere too hot). Check once or twice a day for
the next 5 to 10 days, you will either see mushroom mycelial growth,
or random colors of contaminating bacteria and/or fungi.

Using this technique, with a non-contaminated culture, I've left jars
for months in my closet untouched, and have got super-tiny mushrooms
to sprout. Nothing worth frying up in a stir-fry, but very cool for
something you just left in the cabinet unattended.


Let us know how it goes!

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