Immobilization resins

Figure 3. Adsorption isotherms of free XAD-4 resins and immobilized XAD-4 resins in K-carrageenan in aqueous CH solution and CH fermentation broth. Key O, aqueous, free resin A, aqueous, immobilized resin , broth, free resin A, broth, immobilized resin.

The immobilized XAD-4 resins in E-carrageenan and calcium alginate are non-toxic to the microbial culture. Thus, the adsorbents can be added directly to the fermenting broth. Both fermentation and product separation can occur at the same time (8). As shown in Table 1, the immobilized resin can be recovered from the fermentation broth. The cycloheximide product can be recovered from the immobilized beads by extraction using butyl acetate. The immobilized beads maintained its mechanical strength through the extraction. In some cases, the purity of the cycloheximide in the solvent is close to 95-100% pure. Very limited additional purification such as crystallization may be used to make the final pure product. 

Polyacrylic resins were employed to study how immobilization resin particle size influences Candida antarctica Lipase B (CALB) loading, fraction of active sites, and catalytic properties for polyester synthesis. CALB adsorbed more rapidly on smaller beads. Saturation occurred in less than 30 seconds and 48 h for beads with diameters 35 and 560-710 pm, respectively. Infrared microspectroscopy showed that CALB forms protein loading fronts for resins with particle sizes 560-710 and 120 pm while CALB appears evenly distributed throughout 35 pm resins. The fraction of active CALB molecules adsorbed onto resins not influenced by particle size was less than 50 %. At about 5% w/w CALB loading, decrease in the immobilization support diameter from 560-710 to 120,75 and 35 pm increased conversion of s-CL to polyester (20 to 36, 42 and 61%, respectively, at 80 min). Similar trends were observed for condensation polymerizations of 1,8-octanediol and adipic acid. 

The activity of CALB immobilized on resins 1 to 4 (see Table 1) was assessed by s-CL ring-opening polymerizations. All immobilized resins have similar CALB loading (5.1 to 5.7 %-by-wt) and water content (1.4 to 1.9%). As shown previously , different chemical shifts are observed for methylene protons (-OC//2-) of e-CL monomer, PCL internal repeat units and chain terminal -012-OH moities. Hence, by in situ NMR monitoring, monomer conversion and polymer number average molecular weight (A/ ) were determined. 

The activity of CALB immobilized on resins 1 to 5 (see Table 1) was assessed by s-CL ring-opening polymerizations. All immobilized resins have... 

Venkatesan K.A., Selvan B.R., Antony M.P., Srinivasan T.G., Vasudeva Rao P.R. Extraction of palladium (II) from nitric acid medium by imidazolium nitrate immobilized resin. Hydrometallurgy 2007 86 221-229. 

High enzyme cost Secretory enzymes High-expression host High-cell-density fermentation Simple enzyme purification techniques Heat precipitation Ammonia sulfate precipitation Simple adsorption and immobilization Resin-free chromatographic separation Multi-enzyme co-immobilization and co-purification... 

The same resin has been employed to fabricate a sensor. Immobilized resin is packed in a glass tube (50 X 3 mm inner diameter) placed in front of a photomultiplier tube. The system can be used for the determination of isoniazide, adrenaline, and isopren-aline in pharmaceuticals by insertion of the sample in a carrier of water. 

Kiniwa H, Doi Y, Nishikaji T, Ogata N (1987) Poly(alpha-amino acid)-immobilized polymer adsorbents for optical resolution.3. A total chromatographic optical resolution on poly(N-5-benzyl-L-glutamine)-immobilized resin. Makromol Chem 188 1851-1860... 

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