Foam fractionation as a method to separate endotoxin from recombinant biotechnology products

The objective of this study was to evaluate the feasibility of foam fractionation for removal of contaminating endotoxin from biotechnology products, including plasmid DNA and recombinant proteins. After foam fractionation, alone and with bovine serum albumin and Triton X-100 as pro-foaming agents, FITC-labeled endotoxin remains in the bulk solution. These studies suggest that foam fractionation will be ineffective in the purification of plasmid DNA solutions, which are not surface-active and remain in the bulk solution with endotoxin. These data support the use of foam fractionation as an effective method for separating surface-active recombinant proteins, which will concentrate in the foam, away from endotoxin.