Effect of electrostatic interactions on the ultrafiltration behavior of charged bacterial capsular polysaccharides

Abstract

Charged polysaccharides are used in the food industry, as cosmetics, and as vaccines. The viscosity, thermodynamics, and hydrodynamic properties of these charged polysaccharides are known to be strongly dependent on the solution ionic strength because of both inter- and intramolecular electrostatic interactions. The goal of this work was to quantitatively describe the effect of these electrostatic interactions on the ultrafiltration behavior of several charged capsular polysaccharides obtained from Streptococcus pneumoniae and used in the production of Pneumococcus vaccines. Ultrafiltration data were obtained using various Biomax™ polyethersulfone membranes with different nominal molecular weight cutoffs. Polysaccharide transmission decreased with decreasing ionic strength primarily because of the expansion of the charged polysaccharide associated with intramolecular electrostatic repulsion. Data were in good agreement with a simple theoretical model based on solute partitioning in porous membranes, with the effective size of the different polysaccharide serotypes evaluated using size exclusion chromatography at the same ionic conditions. These results provide fundamental insights and practical guidelines for exploiting the effects of electrostatic interactions during the ultrafiltration of charged polysaccharides. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1531-1538, 2016.

Purification of a conjugated polysaccharide vaccine using tangential flow diafiltration

“…The selectivity values for the binary mixture are similar to those obtained with the pure components, suggesting that intermolecular interactions between the free and conjugated polysaccharides are relatively unimportant for the conditions examined in Figure . However, data obtained at higher polysaccharide/conjugate concentrations showed much lower selectivity at high filtrate flux due to fouling of the membrane (data not shown), consistent with results obtained previously for the pure polysaccharide (Hadidi et al, ).…”

“…Recent work by Hadidi, Buckley, and Zydney, (, ) and Emami, Motevalian, Pepin, and Zydney () have provided new insights into the factors controlling the ultrafiltration of pneumococcal polysaccharides, highlighting the important role of concentration polarization and fouling in determining the overall rate of polysaccharide transmission. In addition, Emami et al () showed that highly charged polysaccharides underwent elongation during tangential flow filtration (TFF), resulting in much greater fouling (and polysaccharide retention) in TFF cassettes compared with either stirred cell or hollow fiber modules.…”

Interactions between protein molecules and the virus removal membrane surface: Effects of immunoglobulin G adsorption and conformational changes on filter performance

“…Membrane fouling is commonly observed regardless of filter type and two main causes for the related decline in filter performance have been proposed . First, the adsorption of proteins onto a wide variety of membrane surfaces (caused by protein‐surface interaction) reduces the effective size of the membrane pores and causes caking on the membrane surface. Lim et al reported that membrane fouling caused by the formation of a dense and compact foulant layer on the membrane surface generated significant flux decline during the filtration of gelatin with an ultrafiltration membrane, especially at the gelatin isoelectric point .…”

A Review on Current Strategies for Extraction and Purification of Hyaluronic Acid

“…The sterile final product was obtained with a 65% yield, obtaining 5–6 g/L HA and a molecular weight of about 4 × 10 6 Da. When dealing with the processing and recovery of molecules via membrane processes, an important aspect that must be studied is the relevant effect of electrostatic interactions between membrane materials and the solutes [ 49 , 50 , 51 ].…”