Synthetic membranes in biotechnology: Realities and possibilities

Heath, Carole A.; Belfort, Georges

doi:10.1007/bfb0046197

Cited by 19 publications

(7 citation statements)

References 137 publications

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“…Many enzymes are active at these interfaces. 45,46 When an enzyme is on the membrane, in order for reaction to occur, substrate (S) has to be moved to enzyme sites, and product (P) has to be transported from the reaction sites to the other side of the membrane 29,47 as illustrated in Fig. 1.…”

Section: Tsp-emr: Basic Needsmentioning

confidence: 99%

Enzymatic membrane reactors: the determining factors in two separate phase operations

Agustian¹,

Kamaruddin²,

Bhatia³

2011

J of Chemical Tech & Biotech

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A two separate phase-enzymatic membrane reactor is an attractive process since it has a large interfacial area and exchange surfaces, simultaneous reaction and separation and other benefits. Many factors influence its successful operation, and these include characteristics of the enzyme, membrane, circulating fluids and reactor operations. Although the operating conditions are the main factor, other factors must be considered before, during or after its application. At the initial stage of reactor development, the solubility of substrates and products, type of operation, membrane material and size, enzyme preparation and loading procedure, and cleanliness of the recirculated fluids should be specified. The immobilization site, reactor arrangement, dissolved or no-solvent operation, classic or emulsion operation and immobilized or suspended enzyme(s) are determined later. Some factors still need further studies. Utilization of the technology is described for use from multigram-to plant-scale capacity to process racemic and achiral compounds. The racemates were resolved primarily by kinetic resolution, but dynamic kinetic resolution has been exploited. The technology focused on hydrolytic reactions, but esterification processes were also exploited.

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Section: Tsp-emr: Basic Needsmentioning

confidence: 99%

Enzymatic membrane reactors: the determining factors in two separate phase operations

Agustian¹,

Kamaruddin²,

Bhatia³

2011

J of Chemical Tech & Biotech

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“…Benzophenone (BP) was selected as photoinitiator, because after UV irradiation it can efficiently create polymer radicals via H abstract i~n ,~~h e n c e it is frequently used in such applicaifferent variants to apply the initiator had been realized previously in heterogeneous surface grafting: (a) dispersion of initiator in the polymer before film preparation," (b) sorption onto the surface from the gas phase or from solutions (soaking) and subsequent solvent evapo- 1,12,15,16,19,30 (c) coating the surface with the initiator suspended in another polymer which is considered as inert toward grafting,l3.l4 and (d) application together with monomer from the gas phase or from solution. '5~'6~'9 In our studies a simple coating procedure (item (b), above) was applied because: (1) B P as a n additive in the membrane casting solution (cf. (a)) changes properties of the prepared membrane; (2) an additional polymer layer (as in (c)) could irreversibly damage the microporous membrane structure; tions~11,13-15,17,30 D (3) homopolymerization (expected with (d)) should be limited as much as possible.…”

Section: Membrane Coating With Photoinitiatormentioning

confidence: 99%

“…Membrane samples were placed in the center of a thermostatable reaction chamber (diameter: 100 mm) with gas entrance and exits, equipped with either a glass or a quartz window ( Figure 1 Experimental setup for gas phase photo graft polymerization onto membranes: 1) Illumination system, including UV lamp HBO 350, quartz mirrors, and collimating lens; 2) reactor light entrance window (glass or quartz, exchangeable); 3) membrane sample; 4) gas supply from nitrogen tank; 5) flow meter; 6) thermostat; 7) temperature-controlled monomer reservoir; 8) temperature-controlled reactor; 9) exiting monomer sorption bottle.…”

Section: Photo Craft Polymerization Of Acrylic Acidmentioning

confidence: 99%

Gas‐phase photoinduced graft polymerization of acrylic acid onto polyacrylonitrile ultrafiltration membranes

Ulbricht

Oechel

Lehmann

et al. 1995

J of Applied Polymer Sci

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SYNOPSISHeterogeneous surface modification of polyacrylonitrile (PAN) ultrafiltration (UF) membranes is realized with UV irradiation-initiated graft polymerization of acrylic acid (AA) from the gas phase onto photoinitiator (benzophenone, BP)-coated samples. In the absence of monomer, PAN functionalization by ketyl radicals dominates after UV excitation of sorbed BP. With AA, graft and total polymer yield increase with B P loading and UV irradiation time. Average molecular weight and distribution of PAA homopolymer-formed in parallel during graft polymerization-are analyzed with gel permeation chromatography. Morphology of PAN-gr-AA UF membranes is checked with scanning electron micrographs (SEMs) and atomic force microscopy. Chemical changes are characterized with FTIR-ATR spectroscopy and SEM/EDX analyses, indicating a pronounced surface selectivity of the graft polymer modification (localized in the upper 5-pm membrane thickness). The amount of grafted PAA systematically reduces membrane permeability and increases dextrane retention, as verified in UF experiments. Photo graft polymer modification of U F membranes will be applied to adjust membrane performance by controlling surface hydrophilicity and permeability using other monomers and/or further graft polymer functionalization. 0 1995

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“…It is possible to integrate both functions, efficient biocatalysis and separation, within one structure, by enzyme immobilization on synthetic ultra‐ or microfiltration (abbreviated UF or MF, respectively) membranes 1–3. Enzymes immobilized on artificial synthetic membranes are applied in, for example, biosensors or enzyme membrane reactors for preparative substrate conversion 4–6. There are many methods for enzyme immobilization on membranes, such as adsorption, entrapment, covalent binding 7,8.…”

Section: Introductionmentioning

confidence: 99%

Polyacrylonitrile Enzyme Ultrafiltration and Polyamide Enzyme Microfiltration Membranes Prepared by Diffusion and Convection

Dayal¹,

Godjevargova²

2005

Macromolecular Bioscience

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Glucose oxidase (GOD) and catalase (CAT) were covalently immobilized onto three types of polyacrylonitrile (PAN 1, PAN 2, and PAN 3) ultrafiltration (UF) membranes with different pore sizes and one type of polyamide (PA) microfiltration (MF) membrane by the bifunctional reagent, glutaraldehyde. The initial membranes were pre-modified to generate active amide groups in the PAN membranes and active amino groups in the PA membranes. The PAN 3 membrane contained the highest amount of active groups, and the membrane PA the lowest. The modified membranes were enzyme-loaded by diffusion and convection (UF). The effect of membrane pore size and immobilization methods on enzymatic activity and bound protein were studied. The most effective immobilized system was prepared by diffusion using a PAN 3 membrane as a carrier (bound protein: 0.055 mg/cm(2), relative activity: 87.6%). This membrane had the highest pore size of all the PAN membranes. Despite the highest pore size of PA membrane, the enzyme PA membranes prepared by diffusion showed the lowest amount of bound protein (0.03 mg/cm(2)) and the lowest relative activity (35.38%). This correlates with the lowest amount of active groups found in these membranes. The relative activity was higher for all the enzyme systems loaded by diffusion. The systems prepared by convection of the enzyme solution contained higher amounts of enzymes (0.035-0.13 mg/cm(2) protein), which led to internal substrate diffusion resistance and a decrease in the GOD relative activity (21.55-68.5%) in these systems. The kinetic parameters (V(max) and K(m)) and the glucose conversion of the immobilized systems prepared by diffusion were also studied. [diagram in text].

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Synthetic membranes in biotechnology: Realities and possibilities

Cited by 19 publications

References 137 publications

Enzymatic membrane reactors: the determining factors in two separate phase operations

Enzymatic membrane reactors: the determining factors in two separate phase operations

Gas‐phase photoinduced graft polymerization of acrylic acid onto polyacrylonitrile ultrafiltration membranes

Polyacrylonitrile Enzyme Ultrafiltration and Polyamide Enzyme Microfiltration Membranes Prepared by Diffusion and Convection

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