Downstream processing of recombinant proteins using alternative purification platforms based on ionic liquids

Abstract

Remarkable advances in the treatment of chronic diseases have been achieved with biopharmaceutical-based therapies, a sector that is currently dominated by therapeutic proteins with over 200 protein drugs in the market1. Improvements in the biopharmaceuticals upstream stage have resulted in high yields of the desired product, and shifted the bioprocess bottleneck to the downstream processing, which is currently dominated by chromatography, accounting with more than 70% of total downstream costs2. Aiming at finding new cost-effective, efficient and sustainable technologies for proteins purification, novel polymer-polymer aqueous biphasic systems (ABS) using ionic liquids (ILs) as adjuvants were investigated in the downstream of interferon alfa 2b (IFNα2b) from Escherichia coli BL21 cultures. The phase diagrams of ABS composed by polyethylene glycol (PEG) and polypropylene glycol (PPG), with ILs as adjuvants, were determined at 25 °C. Chloride-based ILs combined with cholinium, imidazolium, pyrrolidinium, piperidinium, tetralkylammonium and tetralkylphosphonium cations were investigated. The use of ILs allows the selective removal of the protein impurities present in the culture medium. In summary, the application of ILs allowed to develop effective IFNα2b purification platforms from E. coli based on polymer-polymer-ABS, having significant benefits in terms of economic, biocompatible and environmental issues. References: 1Walsh G, Nat Biotechnol, 2018, 36, 1136-1145; 2Azevedo AM, Rosa PAJ, Ferreira IF, et al. Trends Biotechnol, 2009, 27, 240-247.