We have a few Strep-tactin columns that had some growth in them and we would like to regenerate the columns back since the resin is quite expensive. Basic goal: remove the brown stuff.
So far, I've killed whatever living material there is with 20% EtOH and 0.5 N NaOH. After cleaning out the columns with Tris Buffer, I've tried regenerating the columns with Buffer with HABA and the resin is a bit redder than before (typical reflection of good regeneration). However, rinsing out the columns again still leaves behind a brownish color. There is also a good deal of black particulate in the resin.
I'm curious what methods exists to clean out a contaminated column.