during my work with gel chromatography column , i put my crude sample of isolated microbial proteases inside the column and put the acetate 5.6 buffer as eluent after finishing this purification step . i wash the resin twice with the acetate buffer 5.6 then leave it in room temp. for two weeks then after making my assays on the results of this column i take the column to work the same previous work but on Tris-HCL buffer 8.3 suddenly i found a white fungi growing on the surface of the resin ,, i wach the resin with ehtanol 10% twice then with distal water twice then with my newly working buffer a blue peak appears inside the resin i shocked ................till now i cant know how to sterilize it ?