FCCT Biochemistry Lab:M9 medium/minimal

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We used to prepare the plain M9 medium as follows:

900 ml sterile water
100 ml M9 salts stock solution
1 ml autoclaved 1 M MgSO4
0.1 ml autoclaved 1 M CaCl2

M9 salts stock solution (10x) is:

60 g Na2HPO4 x 7 H2O
30 g KH2PO4
5 g NaCl
10 g NH4Cl
add water to 1000 ml and autoclave


Note 1: salts that are added last often tend to precipitate. I didn't bother about it too much as obviously it didn't influence bacterial growth. There might be a way to avoid precipitation (eventually adding magnesium and calcium first) but I didn't investigate this in detail.

Note 2: The M9 stock solution here is essentially as in the M9 salts recipe just that the concentration of Na-phosphate is not exactly the same - see the Talk section therein.