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Minimal A medium is a defined minimal medium for E. coli growth. It uses (NH4)2SO4 as a nitrogen source. Itis somehwat less tringent thahn M9 olr It is somewhat less stringent than M9 or M63 media. MG1655 camn can grow in it iwth douybling with doubling times of ~80-110 minutes at 37C, depending on the cabron carbon source. DH5alpha does not seem to grow well in minimal A medium
I've used glucose (0.2%), glycerol (0.05%), and succinic acid (0.2%) as carbon sources. 0.2% glycerol appears to inhibit growth of MG1655. Succinic acid gives a lower pH than lgucose glucose (6.4 as opposed to 7.0). The cells grow slowly in succinic acid. It's possible tha that they woudl would grow better in a succinate salt of some sort (Sigma has sodium succinate). It also might be true that you want hte the succinate ion at 0.2%. Many other carbon sources could be used.
Minimal A medium includes magnesium added from a dstock stock solution. it may also have vitamins added (vitamin B1, also known as thiamine, is often added, and I always add it) to 1ug/L. If amino acids need to be added, they are added to 50ug/L. All tyhree three of these don't like to be autoclaved, which is why they're added separately. The vitamins and amino acids are optioonaloptional, althoguh although I always use thiamine, but the magnesium is required.
A few miscellaneous notes on minimal medium are worth writing down. Cultures typically grow to OD600 of 1-2 given 0.2% carbon source. Because their doubling times are so long, sometimes they dcondon't grow all the way into stationary phase in an overnight culture. Lag phase from stationary to log phase is womehre somewhere around an hour or so, but lag phase from rich medium to minimal medium is longer. Induction curves tned tend to be clearner cleaner in minimal medium, probably becausde hter eisnbecause there isn't any nutritional shiftin gduring shifting during growth. The cells are often slightly smaller in diamerterdiameter, which might mean tha tmicrofluidic that microfluidic microscopy chips will need to be redesigned.
The recipe given ehre here is taken from HJ.H. Miller, A short course in becerial bacterial genetics. Minimal media recipes seemto seem to come in any number of variations, so it's worth it to cite the one you use.
1X minmal minimal A medium
- 100mL 10X minimal A salts
- 1mL 1M MgSO4-7H207H2O
- 100uL 10g/L thiamine-HCl
- carbon source as desired (often 0.2%, 10mL of a 20% stock solution)
- dH20dH2O - to 1L
Sterile filter to sterilize. If you'd rather autoclave, autoclage autoclave the minimal A salts and water together, cool, then add magnesium, thiamine, and carbon source. I prefer to use dH20 dH2O rather than Milli-Q water in some hope that trace minerals will be provided. This is probably superstition on my part.
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