Syed M. Saufi

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

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 β‐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 β‐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 β‐Lactoglobulin and α‐Lactalbumin, respectively. In batch fractionation of whey, the MMM showed selective binding towards β‐Lactoglobulin compared to other proteins. The dynamic binding capacity of β‐Lactoglobulin in whey solution was about 80 mg/g membrane (24 mg β‐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. Biotechnol. Bioeng. 2009;103: 138–147.

Simultaneous anion and cation exchange chromatography of whey proteins using a customizable mixed matrix membrane.

Membrane chromatography can overcome some of the limitations of packed bed column chromatography but preparation of adsorptive membranes usually involves complex and harsh chemical modifications. Mixed matrix membranes (MMMs) require only the physical incorporation of an ion exchange resin into the membrane polymer solution prior to membrane casting. An advantage of MMMs not previously exploited is that resins with differing adsorptive functionalities can be conveniently embedded within a single membrane at any desired ratio. This presents the opportunity to customize an adsorptive membrane to suit the expected protein profile of a raw feed stream e.g. bovine whey or serum. In this work, a novel mixed mode interaction MMM customized to extract all major proteins from bovine whey was synthesized in a single membrane by incorporating 42.5 wt% Lewatit MP500 anionic resin and 7.5 wt% SP Sepharose cationic resin into an ethylene vinyl alcohol base polymer casting solution. The mixed mode MMM developed was able to bind both basic and acidic proteins simultaneously from whey, with binding capacities of 7.16±2.24 mg α-lactalbumin g(-1) membrane, 11.40±0.73 mg lactoferrin (LF)g(-1) membrane, 59.21±9.90 mg β-lactoglobulin g(-1) membrane and 6.79±1.11 mg immunoglobulin Gg(-1) membrane (85 mg total protein g(-1) membrane) during batch fractionation of LF-spiked whey. A 1000 m(2) spiral-wound membrane module (200 L membrane volume, 1m(3) module volume) is predicted to be able to produce approximately 25 kg total whey protein per h.

Methods for purification of dairy nutraceuticals.

Abstract: The properties of the classes of proteins found in bovine milk and increasingly used as nutraceuticals are reviewed. Whey proteins, an important class of dairy nutraceutical products, can be classified as acidic and basic proteins and immunoglobulins. The methods used for their purification, including ion exchange, chromatography and membranes are described.

Effect of VIPS fabrication parameters on the removal of acetic acid by supported liquid membrane using a PES–graphene membrane support

In this study, the removal of acetic acid by supported liquid membrane (SLM) using hybrid polyethersulfone (PES)–graphene membrane prepared by vapor induced phase separation (VIPS) was investigated. The effects of graphene loading, coagulation bath temperature, air exposure time, and air humidity on the morphology, mechanical strength, porosity, and contact angle of the membrane were analyzed. The performance and stability of the hybrid membrane as a SLM support for acetic acid removal were studied. The best PES–graphene membrane support was produced at a coagulation bath temperature of 50 °C, an air exposure time of 30 s and air humidity of 80%. The fabricated membrane has a symmetrical micropore cellular structure, high porosity and high contact angle. Under specific SLM conditions, almost 95% of acetic acid was successfully removed from 10 g L−1 aqueous acetic acid solution. The hybrid membrane remains stable for more than 116 h without suffering any membrane breakage during the continuous SLM process.

Synthesis of Nanofiltration Membrane Developed from Triethanolamine (TEOA) and Trimesoyl Chloride (TMC) for Separation of Xylose from Glucose

Synthesis of thin film composite (TFC) nanofilt ration (NF) membrane has experienced tremendous development since the concept of interfacial polymerisation (IP) was first introduced. One of its new application is on the separation of xylose from glucos e in biomass hydrolysate. In this present study, NF TFC membrane has been produced through interfacial poly merisation by manipulation the concentration of triethanolamine (TEOA) at 35 min reaction time with 0. 15 % w/v of trimesoyl chloride (TMC). The membrane was then characterised in term of their chemical and physical properties, and separation performance between xylose and glucose. The growth of thin layer f ilm depends on concentration of TEOA as the monomer and reaction time. As concentration of TEOA and re action time increased, the layer of the TFC becomes thicker thus decreases the permeability of the membrane. Contradicted to this study, the lowest and the highest permeability were recorded at 4 % w/v of TEOA and 8 % w/v of TEOA at reaction time of 35-min in TMC. The TFC membrane prepared with 4 % w/v TEOA has high in permeate flux, resultant in high xylose separation of 1.3. Low permeate flux but moderate xylose separation factor of 0.93 was obtained for the TFC membrane prepared with 8 % w/v TEOA.

Removal of Acetic Acid from Aqueous Solution by Polyethersulfone Supported Liquid Membrane

Lignocellulosic biomass can be converted to biofuel, which is one of the renewable energy. To achieve this purpose, acid hydrolysis was used to hydrolyse lignocellulosic materials to fermentable sugars. However, acetic acid, a major inhibitory compound was released during the acid hydrolysis process. Existence of acetic acid significantly suppressed fermentative organisms and decreased the production of ethanol. It is necessary to remove acetic acid inhibitor from biomass hydrolysate prior to the fermentation process. Selective removal of acetic acid from aqueous solution was attempted by using supported liquid membrane (SLM) system based on tri-n-octylamine carrier and sodium hydroxide stripping phase. Polyethersulfone (PES) membrane was prepared by vapour induced phase separation method and used as a matrix support in SLM process. Effects of PES membrane thickness, types of diluent, and flow rate of feed phase were tested. Under favourable condition, almost 86 % of acetic acid was successfully removed from the aqueous solution. The PES SLM system remained stable for 8 h of extraction without any breakage.

Separating xylose from glucose using spiral wound nanofiltration membrane: Effect of cross-flow parameters on sugar rejection

A solution model consisted of two different monosaccharides namely xylose and glucose were separated using a pilot scale spiral wound cross-flow system. This system was equipped by a commercial spiral wound nanofiltration (NF) membrane, Desal-5 DK, having a molecular weight cut off (MWCO) of 150-300 g mol-1. The aim of this present work is to investigate the effect of the cross-flow parameters: the trans-membrane pressure (TMP) and the feed concentration (C0) on the xylose separation from glucose. The filtration experiments were carried out in total reflux mode with different feed concentration of 2, 5, and 10 g/L at different TMP of 5,8 and 10 bar. The performances of the NF membrane were evaluated by measuring the permeate flux and sugar rejection for each experiment. All the samples were quantified using a high performance liquid chromatography equipped by a fractive index detector. The experimental results indicated an increase in pressure from 5 to 10 bar which was a notable increase to the permeate fluxes from 2.66 × 10-3 to 4.14 × 10-3L m-2s-1. Meanwhile, an increase in the C0 increases the xylose rejection. At TMP of 10 bar and C0 of 5 g/L, the observed xylose rejection and glucose rejection were measured at 67.19% and 91.82%, respectively. The lower rejection in xylose than glucose suggested that larger glucose molecule were not able to easily pass through the membrane compared to the smaller xylose molecule. The results of this phenomena proved that NF with spiral wound configuration has the potential to separate xylose from glucose, which is valuable to the purification of xylose in xylose production as an alternative to chromatographic processes.

Batch adsorption of whey protein onto anion exchange mixed matrix membrane chromatography

Mixed matrix membrane (MMM) chromatography is an advanced method for whey protein fractionation. The adsorption capacity of MP500 anion exchange MMM chromatography was evaluated by batch experiments using simulated whey containing a single whey protein component and real whey at pH 6. The binding preference for whey proteins was demonstrated to follow the order: β-lactoglobulin > bovine serum albumin > α-lactalbumin. MP500 based MMM could be used to recover β-lactoglobulin very selectively from whey to produce a single protein component for food ingredient and related applications.