THE EFFECT OF DENATURANTS ON THE CROSS-FLOW MEMBRANE FILTRATION OF ESCHERICHIA-COLI LYSATES CONTAINING INCLUSION-BODIES

Recovery of inclusion bodies from Escherichia coli cell lysates often includes a washing step to remove associated contaminants that may oth erwise interfere with refolding of the solubilized protein. The effect s of denaturants typically used in the washing step on the cell lysate viscosity and membrane filtration performance were examined. Guanidin e HCl alone and in combination with the nonionic detergent, Triton X-1 00, had the greatest effect on the cell lysate viscosity, the dead-end filtration rate and the performance of the crossflow membrane filters . Triton X-100 reduced the dead-end filtration rate, but had less of a n effect than guanidine HCl on permeate flux during crossflow membrane filtration. Urea had minimal effect on either the dead-end filtration rate or the permeate flux and protein transmission during crossflow m embrane filtration. The use of low concentrations of urea along with a PVDF membrane allowed for inclusion body washing without detrimental changes in the permeate flux and protein transmission during crossflow membrane filtration.