Expanded bed adsorption/desorption of proteins with Streamline Direct CST I adsorbent

Abstract

Streamline Direct CST I is a new type of ion exchanger with multi-modal functional groups, specially designed for an expanded bed adsorption (EBA) process, which can capture directly the proteins from the high ionic strength feedstocks with a high binding capacity. In this study, an experimental study is carried out for two-component proteins (BSA and myoglobin) competitive adsorption and desorption in an expanded bed packed with Streamline Direct CST I. Based on the measurements of the single- and two-component bovine serum albumin (BSA)/myoglobin adsorption isotherm on Streamline Direct CST I, the binding and elution conditions for the whole EBA process are selected; and then frontal analysis for a longer timescale and column displacement experiments in a fixed bed (XK16/20 column) are carried out to evaluate the two-component proteins (BSA and myoglobin) competitive adsorption and displacement on Streamline Direct CST I. Finally, the feasibility of capturing both BSA and myoglobin by an expanded bed packed with Streamline Direct CST I is addressed in a Streamline 50 column packed with 300 mL Streamline Direct CST I.

Studies of lysozyme binding to histamine as a ligand for hydrophobic charge induction chromatography

“…Similar phenomena regarding q m were reported for commercial STREAMLINE Direct HST. 2,11 Evidently, HA-S has a better salt tolerance than commercial ion exchange chromatography and HIC beads. Table 1 also showed a small drop in the dissociation constant, K d , with an increase of salt concentration from 50 to 500 mmol/L, consistent with a contribution from hydrophobic interaction to lysozyme adsorption.…”

“…A similar adsorption pattern was also found for protein adsorption on STREAMLINE Direct HST. 2,11 It was argued that hydrogen bonding, electrostatic interaction and hydrophobic interactions all contributed to protein adsorption on the adsorbent. 11,12 For HA-S, since the pK a of the imidazole ring of histamine is 6.04, 29 the ligand is in an uncharged form at pH 7.0 and no charge-charge interaction occurs in the adsorption process.…”

“…2,11 It was argued that hydrogen bonding, electrostatic interaction and hydrophobic interactions all contributed to protein adsorption on the adsorbent. 11,12 For HA-S, since the pK a of the imidazole ring of histamine is 6.04, 29 the ligand is in an uncharged form at pH 7.0 and no charge-charge interaction occurs in the adsorption process. In the HCIC system reported here, aromatic stacking involving imidazole ring of histamine may contribute to the lysozyme adsorption by interacting with aromatic residues (p-p stacking) and with positively-charged residues (cation-p stacking).…”

“…2,11 On the basis of the adsorption isotherms for BSA on STREAMLINE Direct CST I, Li et al speculated that the protein adsorbed on the adsorbent by hydrogen bond interaction instead of chargecharge interaction under a weakly acidic environment. 11 The similar conclusion was affirmed in adsorption isotherm and chromatographic retention of BSA by Gao et al 12 In a combination with equilibrium binding analysis and isothermal titration microcalorimetry (ITC) measurements, Lin et al found that aromatic stacking contributed to protein adsorption on aromatic-based HIC adsorbents (e.g., Phenyl Sepharose). 13 Besides that, a typical HCIC chromatographic process is also influenced by other factors, such as the composition of the liquid phase, pH, and temperature.…”

“…13 Besides that, a typical HCIC chromatographic process is also influenced by other factors, such as the composition of the liquid phase, pH, and temperature. 2,11,12 Therefore, a better understanding of the mechanism of protein adsorption on HCIC beads is indispensable for the development and application of HCIC technology.…”