Purification of high value proteins from particle containing potato fruit juice via direct capture membrane adsorption chromatography

Potato fruit juice (PFJ) is a by-product from industrial starch production. It still contains several valuable components such as amino acids, minerals and proteins. An economic technology for the isolation and purification of different native potato proteins is the ion exchange chromatography, which can be performed either by classical bed chromatography or by membrane adsorption chromatography (MA-IEX). An already published MA-IEX process for the downstreaming of PFJ is based on the following steps: prefiltration/microfiltration, fractionation with MA-IEX, ultra-/diafiltration and finally drying. In order to further minimize process complexity and costs, new MA-IEX-modules were designed and tested in this research project to facilitate the processing of crude, particle-containing solutions using a tangential flow through the membranes. Modules with fleece polymer spacers and extruded polymer spacers, as well as different spacer channel sizes were tested for their binding capacities and their long-term stability. An optimized setup was found for the technical scale. Modules with extruded polymer spacers channel size 250 μm show the highest binding capacities (anion exchanger approx. 0.34 mg/cm2, cation exchanger approx. 0.16 mg/cm2), while the modules with extruded polymer spacers channel size 480 μm show the best long-term stability with 23 passes without intermediary cleaning.