Washing bacteria - (Jun/24/2012 )

Hi there,

What does it mean when it says "wash twice with PBS" regarding bacteria..does it mean after I spin down my bacteria, I pour off the supernatant and then add PBS and then spin again, pour off s/n add more PBS and spin...

OR DOES IT MEAN

just add PBS ensuring the pellet doesn't break up and then pipette out the PBS and then add more and take it out..?

cheers,
b_06er

It means resuspend the bacteria in PBS, then re-pellet. If you leave the pellet undisrupted, the PBS won't be able to wash away all of the residual media that is coating the cells in the pellet.