Recombinant therapeutic proteins derived from E. coli require robust endotoxin removal, ideally performed using multiple process steps providing orthogonal and robust clearance. Typical recovery processes for E. coli expressed proteins consist of cell harvest by centrifugation, homogenization, collection of inclusion bodies by centrifugation, solubilization, refold, and clarification by depth filtration. Endotoxin clearance across the recovery operations is usually on the order of one log. Here, we demonstrate that endotoxin clearance can be enhanced to five logs by using 16% polyethylene…