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How can we
grow bacteria?
We need a suitable
surface and container to grow bacteria. Petri
dishes are used in biology laboratories but on the island, bottle
top lids were a perfect substitute.
As well as a
stable physical environment, bacteria need nutrients on which to
feed. Traditionally, scientists have used types of jelly. The most
common are agar
and gelatin.
Agar is made by boiling seaweed in fresh water, straining and reducing
it to a thick syrup. When it cools it forms a jelly-like substance.
Is agar alone
sufficient for growing bacteria?
Bacteria need vitamins, proteins and minerals not found in agar
and so we add a nutrient
broth, which is also referred to as 'media' by microbiologists,
to the Petri dishes.
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