US Patent 7888098 Scalable process for protein purification

The invention provides a process for the purification recombinantly expressed, self-assembled VLP from the homogenate of a bacterial host, wherein the process can be scaled up to a commercial production scale in a cost effective manner. The process comprises a first chromatography using an anion exchange matrix, a second chromatography using hydroxyapatite and, optionally, a size exclusion chromatography. VLP preparations obtained by the process of the invention are essentially free of endotoxin contaminations.