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Pseudomonas aeruginosa growth very slow in N-minimal media - (Dec/27/2011 )

Hi All,

I am growing Pseudomonas aeruginosa WT strain in N-Minimal media at low Mg++ concentration (8uM/ml). But, it is growing very slowly. I had grown PA in 25ml media from picking single colony, over night. But, I got only 2mg bacteria after lyophilization. On the basis of this observation I have two question.

1) Is that Okay, if i grow it for a longer time (more than 24hr)?
2) Will the bacteria begin to die, If it continues to grow for a longer time (24hr) due to Mg++ deficiency?

Kindly give me your suggestions.



If you are concerned over bacterial viability, measure cfu counts (by plating) and the OD600 at different stages of growth. If the OD600 stagnates, or the cfu counts drop, you have grown too far into the stationary phase. Personally, I think it will take longer than 24hours for the bacteria to reach stationary phase in minimal media (probably will take several days).

One tip is to first have a dense culture growing (stationary phase, probably growing for >24hours), and then sub-culture 1/100 or 1/50. This way your culture would reach exponential growth phase faster than if you started a culture by colony picking...