Freimoser:Recipes:Yeast:SC Sfree

=Sulfur free SC-medium (self mixed SC medium)=

Remark:
This recipe describes the mixing of a sulfur free SC-medium. All sulfur sources in “normal” SC-medium are replaced by other salts, mostly chlorides. The changes are also indicated. The phosphate source is separate in order to allow mixing of media with different phosphate content. The 20x salt solution, 100x phosphate source and 40% glucose solution were autoclaved. All other solutions were filter sterilized. The described procedure works, but it is possible that there are simpler solutions. But it is not possible to make a stock solution of all trace elements for example. The concentrations in parentheses indicate approximate concentrations in the final 1x medium.

20x Salt solution, 500 ml

 * MgCl2: 16 g (4 mM)
 * NaCl: 1 g (1.7 mM)
 * CaCl2 x 2 H2O: 1 g (1 mM)

1000x trace element solution 1, 10 ml

 * Boric acid (H3BO3): 0.05 g (8 μM)
 * CuCl2 x 2 H2O: 0.004 g (0.25 μM) (replaces CuSO4)
 * KI (potassium iodide): 0.01 g (0.6 μM)
 * C4H10O6Zn (zinc acetate): 0.055 g (2 μM) (replaces ZnSO4)

1000x MnCl2 x 4 H2O (manganese chloride):

 * 0.04 g in 10 ml (1000x) (2 μM) (replaces MnSO4)

1000 x Na2MoO4 (sodium molybdate):

 * 0.02 g in 10 ml (1000x) (1 μM)

500x FeCl3 x 6 H2O (ferric chloride):

 * 0.02 g in 10 ml (500x) (1.5 μM)

100x NH4Cl (ammonium chloride):

 * 2 g in 10 ml (37.8 mM)

100 x phosphate source, 100 ml

 * KH2PO4: 10 g (7.5 mM)

20x Glucose (C6H12O6):

 * 40% (20x)

Complete amino acid mixture
We use commercially available complete amino acid mixtures and make a 10x stock solution that is filter sterilized.

10x MES buffer (2-(N-morpholino)ethanesulfonic acid):

 * 0.5 M, pH 6 (10x)

Mixing
Volumes for the preparation of 50 ml 1.1x SC-S medium. For 1 ml final medium, 900 μl of this 1.1x stock and 100 μl of any sulfur source are used.