Fractionation of β‐Lactoglobulin from whey by mixed matrix membrane ion exchange chromatography

Abstract

Mixed matrix membranes (MMMs), which incorporate adsorptive particles during membrane casting, can be prepared simply and have performances that are competitive with other membrane chromatography materials. The application of MMM chromatography for fractionation of beta-Lactoglobulin from bovine whey is described in this article. MMM chromatography was prepared using ethylene vinyl alcohol polymer and lewatit anion exchange resin to form a flat sheet membrane. The membrane was characterized in terms of structure and its static and dynamic binding capacities were measured. The optimum binding for beta-Lactoglobulin was found to be at pH 6.0 using 20 mM sodium phosphate buffer. The MMM had a static binding capacity of 120 mg/g membrane (36 mg/mL membrane) and 90 mg/g membrane (27 mg/mL membrane) for beta-Lactoglobulin and alpha-Lactalbumin, respectively. In batch fractionation of whey, the MMM showed selective binding towards beta-Lactoglobulin compared to other proteins. The dynamic binding capacity of beta-Lactoglobulin in whey solution was about 80 mg/g membrane (24 mg beta-Lac/mL of MMM), which is promising for whey fractionation using this technology. This is the first reported application of MMM chromatography to a dairy feed stream.

Recovery of lactoferrin from whey using cross-flow cation exchange mixed matrix membrane chromatography

“…The main objective of grinding the SP Sepharose resin was to improve the adhesion and homogeneous distribution of the resin within the membrane matrix rather than to change the adsorption capacity of the particles. However, smaller resin particles may also improve the dynamic binding capacity in MMM because the diffusion path lengths to the internal ion exchange sites would decrease and there would be a simultaneous increase in the interfacial surface area between permeate and resin [25].…”

“…Mixed matrix membranes were prepared following procedures reported previously [25] but using SP Sepharose resin as the embedded adsorbent. A homogenous EVAL polymer solution, consisting of 15 wt% EVAL polymer and 15 wt% 1-octanol in DMSO was used.…”

“…Ground SP Sepharose resin (38 m) was added to the prepared polymer solution to make a 30% weight fraction (relative to the EVAL content in the polymer solution) and this mixture was stirred until a homogeneous casting slurry was obtained. A flat sheet MMM was cast on a glass plate from the slurry, as previously described [25] and the wet MMM was then freeze-dried to remove water without affecting the structure of the membrane.…”

“…Whey was prepared from skim (0.05% fat) milk purchased from the local retail store as previously described [25].…”

“…In previous work [25], we applied anion MMM chromatography to whey protein fractionation, using an ethylene vinyl alcohol (EVAL) base membrane and a Lewatit ® MP500 anion exchange resin as an adsorbent particle in the membrane. The resultant anion exchange MMM yielded selective binding of ␤-Lac over the other proteins in whey.…”