Concentrating bacterial cells - (Aug/11/2014 )
Any one have any tips on how to concentrate bacterial cells? My team is trying to work with an idea from another paper of using bacteria at a concentration of 10^10 cells per ml to apply to another application. Let's say you typically have 10^8 cells per ml in an overnight culture. Any ideas how to get up to 10^10 cells per ml? I was going to count the cells to find the "specific" concentration, and then spin it down at 5000 g for 15 min, remove some of the supernatant, resuspend it, and recount it to see what my concentration is. But it seems that may not bring me to 10^10, but only concentrate the first part. For example, 5 x 10^8 cells per ml, the 5 would decrease, instead of the exponent increasing. Anyone have any links or tips to protocols?
You can't force bacteria to grow more dense then they like.
So you need to spin (gently).
If you know how many cells do you have per ml and you know how many ml of culture you spin, you know overal amount of bacteria there. If you measure what volume of supernatant you removed you may calculate in which (lower) amount of media you should resuspend the palet to get the desired concentration.
You didn't write what overal amount of 10^10 cells per ml you actually need. That is the overal amount you need to spin, at least, in the first place.
Why are you so limited in volume of initial culture?