Method for removing endotoxin from proteins
Disclosed is a method for removing endotoxin from proteins. Also disclosed are products made by using the method. The method may be used, for example, to produce endotoxin-free lactoferrin. Bovine milk-derived lactoferrin may be produced in commercial quantities by the method, and endotoxin-free bovine lactoferrin may be used for a variety of therapeutic uses, including improving wound healing.
1. A method for removing endotoxin bound to lactoferrin in an enriched liquid lactoferrin composition, the method comprising
a) binding the lactoferrin to a cation exchange resin;
b) washing the resin with water;
c) eluting the endotoxin using a low-ionic strength solution in the absence of added surfactant; and
d) eluting the lactoferrin with a high ionic strength solution to produce an eluted lactoferrin product
wherein the enriched liquid lactoferrin composition is derived from whey and wherein the enriched liquid lactoferrin composition comprises greater than 2 percent lactoferrin.
2. The method of claim 1 wherein the low-ionic strength solution is a 0.01 to 0.5 molar salt solution.
3. The method of claim 2 wherein the low-ionic strength solution is a 0.25 to 0.35 molar salt solution.
4. The method of claim 1 wherein the high ionic strength solution is an 80-100 mS/cm salt solution.
5. The method of claim 1 additionally comprising the steps of filtering the eluted lactoferrin and drying the eluted lactoferrin.