One-step purification process to obtain analytical grade phycoerythrin from Porphyridium sp. using hydrophobic interaction chromatography (HIC)

Abstract

Phycoerythrin (PE) is a highly valued protein pigment with notable properties in various applications, including human health, pharmaceuticals, cosmetics, and the biomedical industry. High-purity PE production schemes often involve several purification steps, which can be costly, result in yield losses, and potentially lack scalability. This study proposes a one-step purification process based on hydrophobic interaction chromatography (HIC) to produce analytical-grade PE from an ionic liquid (IL)-based crude extract from Porphyridium sp. The HIC approach effectively leveraged the ILs' ionic strength using different resins with varying hydrophobic ligands, ligand concentrations, and agarose matrix properties. The purity achieved is shown as a function of the recovered PE yield, enabling the selection of a suitable resin based on the required purity and recovery for the PE applications. The highest recovery yield within the analytical grade was obtained with Butyl-S Sepharose 6 Fast Flow resin (73.0%). In contrast, the highest PE purity was achieved using Butyl Sepharose High Performance resin, yielding a maximum value of 8.2, a 9.9-fold increase compared to the crude extract. This resin also produced high purity PE relative to phycocyanin (A₆₂₀/A₅₄₅ = 0.01), comparable to commercial PE standards. Furthermore, the purification process was also highly effective for extracts with reused ILs, an essential consideration for the sustainability of the process when working with this type of solvent. Ultimately, this study provides valuable insights into the behaviour of PE when purified using diverse hydrophobic resins, which can guide the selection of the most appropriate resin based on the desired purity and yield targets.