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548 results on '"Lin, Dong-qiang"'

120. Mathematical modelling of expanded bed adsorption - a perspective on in silico process design

Author

Koppejan, V.W., Ferreira, Guilherme, Lin, Dong Qiang, and Ottens, M.

Subjects
Chromatography, Bioseparations, Downstream, Mathematical Modelling, Process Development
Abstract

Expanded bed adsorption (EBA) emerged in the early 1990s in an attempt to integrate the clarification, capture and initial product concentration/purification process. Several mathematical models have been put forward to describe its operation. However, none of the models developed specifically for EBA allows simultaneous prediction of bed hydrodynamics, mass transfer/adsorption and (unwanted) interactions and fouling. This currently limits the development and early optimization of EBA-based separation processes. In multiphase reactor engineering, the use of multiphase computational fluid dynamics has been shown to improve fundamental understanding of fluidized beds. To advance EBA technology, a combination of particle, equipment and process scale models should be used. By employing a cascade of multiscale simulations, the various challenges EBA currently faces can be addressed. This allows for optimal design and selection of equipment, materials and process conditions, and reduces risks and development times of downstream processes involving EBA.

Published
2018

125. Mixed-Mode Expanded-Bed Adsorption for Human Serum Albumin Separation

Author

Wu, Qi-Ci, Zhang, Qi-Lei, Gao, Dong, Nie, Lei, Wang, Hai-Bin, Yao, Shan-Jing, and Lin, Dong-Qiang

Abstract

Mixed-mode chromatography (MMC) is a promising technology for protein separation with high adsorption capacity, good selectivity, salt-tolerance, and facile elution. Expanded bed adsorption (EBA) can capture target proteins directly from bioparticle containing crude feedstock without solid–liquid separation. In this study, MMC and EBA were combined to develop a mixed-mode EBA technique for human serum albumin (HSA) separation. Two mixed-mode EBA resins (using quartz-densified agarose beads and tungsten carbide/agarose composite beads, respectively) with tryptamine as the ligand were prepared (TA-S and TA-T). Static and dynamic adsorption behaviors of HSA were determined under varying conditions and typical adsorption properties of pH dependence and salt-tolerance were found. The performance of the resins in expanded bed was studied, and the dynamic binding capacities at 10% breakthrough (Q10%) of TA-S and TA-T at bed expansion of 1.8 were 27.54 and 18.04 mg/mL settled resin, respectively. Moreover, these two resins were used to separate recombinant HSA (rHSA) from Pichia pastorisculture broth. TA-S showed better separation performance and the purity of rHSA monomer reached to 83.3% with the recovery of 91.6% through a two-step elution process. Total content of rHSA monomer and degraded fragment was 99.8%. The results demonstrate that the combination of MMC and EBA would be a potential platform for protein capture with fewer pretreatments and high process efficiency.

Published
2024
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139. High-Throughput Process Development for Recombinant Human Serum Albumin Separation from Pichia pastorisBroth with Mixed-Mode Chromatography

Author

Chu, Wen-Ning, Wu, Qi-Ci, Zhang, Qi-Lei, Yao, Shan-Jing, and Lin, Dong-Qiang

Abstract

Due to the shortage of blood donation and safe issues of blood-derived pathogens, recombinant human serum albumin (rHSA) expressed by Pichia pastorisis a potential substitute for plasma-derived HSA (pHSA). In this work, four commercialized mixed-mode resins (Capto adhere, Capto MMC, MX-Trp-650M, and Nuvia cPrime) and two ion-exchange resins (Q Sepharose FF and SP Sepharose FF) were used for rHSA separation from Pichia pastoriscell culture broth, and loading and elution conditions were optimized via a high-throughput process using microtiter filter plates. The results indicated that resins with cation-exchange groups had better adsorption performance. The loading conditions at pH 4.0 and dilution rate of 1.0 were suitable for SP Sepharose FF, and no dilution worked for mixed-mode resins. The optimal elution pH was determined to be pH 7.0 for SP Sepharose FF, pH 8.0 for MX-Trp-650M and Nuvia cPrime, and pH 9.0 for Capto MMC. Moreover, rHSA separation from Pichia pastorisbroth was performed on column under optimal conditions based on the high-throughput screening. The results showed that no feedstock dilution was needed for Capto MMC and MX-Trp-650M, and separation performance of high dynamic binding capacity at 10% breakthrough (∼50 mg/mL), elution recovery (>95%), and purity (>96%) as well as excellent removal of pigments (A350< 0.080) and HCPs (<581 ppm) could be obtained. The cation-exchange mixed-mode resins (especially MX-Trp-650M) were more suitable for direct capture of rHSA from crude feedstock. The high-throughput method developed can rapidly determine the optimal separation conditions for column chromatographic separation.

Published
2019
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143. Characterization of dextran-grafted hydrophobic charge-induction resins: Structural properties, protein adsorption and transport.

Author

Lin, Dong-Qiang, Yao, Shan-Jing, Liu, Tao, Angelo, James M., and Lenhoff, Abraham M.

Subjects
*DEXTRAN, *AGAROSE, *INVERSE gas chromatography, *IMMUNOGLOBULIN G, *SERUM albumin, *MICROSCOPY
Abstract

The structural and functional properties of a series of dextran-grafted and non-grafted hydrophobic charge-induction chromatographic (HCIC) agarose resins were characterized by macroscopic and microscopic techniques. The effects of dextran grafting and mobile phase conditions on the pore dimensions of the resins were investigated with inverse size exclusion chromatography (ISEC). A significantly lower pore radius (17.6 nm) was found for dextran-grafted than non-grafted resins (29.5 nm), but increased salt concentration would narrow the gap between the respective pore radii. Two proteins, human immunoglobulin G (hIgG) and bovine serum albumin (BSA), were used to examine the effect of protein characteristics. The results of adsorption isotherms showed that the dextran-grafted resin with high ligand density had substantially higher adsorption capacity and enhanced the salt-tolerance property for hIgG, but displayed a significantly smaller benefit for BSA adsorption. Confocal laser scanning microscopy (CLSM) showed that hIgG presented more diffuse and slower moving adsorption front compared to BSA during uptake into the resins because of the selective binding of multiple species from polyclonal IgG; polymer-grafting with high ligand density could enhance the rate of hIgG transport in the dextran-grafted resins without salt addition, but not for the case with high salt and BSA. The results indicate that microscopic analysis using ISEC and CLSM is useful to improve the mechanistic understanding of resin structure and of critical functional parameters involving protein adsorption and transport, which would guide the rational design of new resins and processes. [ABSTRACT FROM AUTHOR]

Published
2017
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