Facile Capture of Recombinant Human Erythropoietin on Mesoporous Affinity Hydrogel Matrix Functionalized with Azoboronate.

Boronate affinity ligands (BALs) have gained attention for glycoproteins capture and recognition due to their unique affinity interaction with glycans. In this paper, the effect of azo immobilization of phenylboronic acid on the reduction of adsorption pH of a recombinant glycoprotein (i.e., rhEPO) on hydrogel microparticles was investigated. To evaluate the influence of intraparticle porosity on protein adsorption, microporous (MicroBead) and mesoporous (MesoBead) agarose beads carrying two levels of amine densities were functionalized with azoboronate ligand. Affinity adsorption of the glycoprotein during static and dynamic adsorptions at relatively low pHs of 8 and 7 was studied. Results revealed successful adsorption of rhEPO at pH = 8 through affinity capture of glycans by azoboronate ligands. Increased amine density provided 1.1 and 1.5 times higher static adsorption capacities and dynamic performance efficiencies, respectively. In addition, adsorption capacities and initial adsorption rates of rhEPO on MesoBeads were respectively 1.4 and 2.5-2.8 times of MicroBeads. Also, at pH = 8, MesoBeads recorded higher dynamic recoveries (59 and 91%) compared with microporous ones (46 and 69%) since mesoporosity facilitates intraparticle mass transfer. Reduction of binding pH from 8 to 7 resulted in a sharp decrease in dynamic recovery (14%), indicating the appropriate binding pH of azoPBA to be above 7. The azoboronate affinity ligand is a leading candidate for capturing glycoproteins at relatively low pH. Also, mesoporous microparticles are appropriate tools in more efficient medium-sized protein binding applications.

Towards rational design of porous nanostructured biopolymeric microparticles for biomacromolecules separation: A case study of intraparticle diffusion facilitation and BSA adsorption on agarose microspheres.

Synthesis and employing advanced materials for emerging applications is of great challenge for the scientific community. Recombinant proteins production and purification is one of the fastest growing fields in the global economy. In this regard, it is essential to fabricate biocompatible low-cost materials with high specificity to enhance purification efficiency. This requires the regulation of mass transfer based on the protein molecular size and interactions with the matrix interface; thus, needs synthesizing novel materials with tuned porosity. In this study, we proposed rational alteration in porous structure of biopolymeric microspheres using appropriate-sized porogen to facilitate intraparticle molecular diffusion. The tailored porous nanostructures, which were generated by phase separation in the polymer blend of agarose and polyethylene glycol, were analyzed with optical and scanning electron microscopy, Fourier transform infrared spectroscopy, water diffusion, and albumin adsorption. The well-tuned beads possessed highly porous structures with dominant mesopores owing to PEG phase migration out of the network. The high speed homogenizer caused an uncommon dense morphology with interwoven two-type porosity. Optimally tuned mesoporous beads with considerably high specific surface area exhibited dramatically fast and enhanced intraparticle diffusion of both water and protein molecules. Thus, the introduced porosity modification is a promising design for enhancing mass transfer in the bio-separation process. Finally, useful insights for developing future smart hydrogel microparticles with tuned porous network for biomolecules purification are provided by the conducted experiments.

Effect of microalgae/activated sludge ratio on cooperative treatment of anaerobic effluent of municipal wastewater.

In this work, capability of the green microalga (MA), Chlorella vulgaris, in treating synthetic anaerobic effluent of municipal wastewater was investigated. While pure C. vulgaris (100 % MA) provided maximum soluble chemical oxygen demand (sCOD) and N-NH4(+) removal efficiencies of 27 and 72 % respectively, addition of activated sludge (AS) to MA in different mass ratios (91, 80, 66.7, 9 % MA) improved wastewater treatment efficiency. Thus giving maximum sCOD and N-NH4(+) removal efficiencies 85 and 86.3 % (for MA/AS = 10/1), respectively. Utilizing AS without C. vulgaris, for treating the synthetic wastewater resulted in 87 % maximum sCOD and 42 % maximum N-NH4(+) removal efficiencies. Furthermore, algal growth and specific growth rates were measured in the systems with microalga as the dominant cellular population. As a result, faster algal growth was observed in mixed systems. Specific growth rate of C. vulgaris was 0.14 (day(-1)) in 100 % MA and 0.39 (day(-1)) in 80 % MA. Finally, data gathered by online measurement of dissolved oxygen indicate that algae-activated sludge mixture improves photosynthetic activity of examined microalga strain during anaerobic effluent treatment.