recombinant ecoli in log phase overnight media suggestion
Posted 17 November 2010 - 07:37 PM
Can you please recommend any media that will maintain our culture in log phase overnight. We see protein expression even in earlier case, but we would like to increase the yield. we incoulate 10% of starter to Fermentation media.
Posted 17 November 2010 - 08:52 PM
That is not an easy request, but here are my thoughts.
1. Reduce the incubation temperature.
This will reduce growth rate, and thus increasing the duration that the culture spends in log phase.
Reduce growth rate will also reduce the oxygen demand of the culture, and cause the bacteria to shift to a more efficient metabolism. The end result is a higher cell density at stationary phase.
2. Increase culture volume(with concurrent increase increase in oxygenation) or reduce the number of cells used to inoculate the culture..
3. use a richer medium.
That would increase cell yield, but maintaining the culture in log phase overnight would probably not be achieved.
4. Use a fermenter which can constantly add and removes culture... a constant density fermenter.
As the cell density increases, culture is remove from the fermentor and new fresh medium is added. If the outflow and inflow are balance correctly, the culture can be kept in log phase. The new medium added also keeps concentration of growth inhibitory products from building up. Cells are pelleted from the culture removed from the fermenter.
5. Added the starting culture early in the morning and harvest the cells in the evening.
Thus the problem of maintaining log phase overnight culture is removed.
Posted 17 November 2010 - 11:16 PM