I need to grow a Met- Trp- E.coli in a defined media with addition of
Met and Trp. I would much prefer to have used BL21 or a prototrophic K12
but the expression is just that much better in that particular auxotroph
What I am struggling on finding is how much amino acid does one actually
need to add per litre if I say we will get up to say 5x10E10cells per
According to NEB's protein data info at the back of their RE catalogue,
total protein at a cell density of 10E9 is 0.15g so at my cell density
that will be 7.5g with a theoretical wet weight of roughly 45g/litre. We
may even double or triple that in a fed batch fermentation. If we say
roughly 5% of each amino acid then we would have needed a minimum of
0.375g each of Met and Trp per litre at the 5 x 10E10cells/ml.
Is that a sensible way to look at it and does that aa figure make sense?
Thanks for any insights.
I love deadlines. I especially like the whooshing noise they make as
they go flying by.