Chapter 10
Effects of Porous Polyacrylic Resin Parameters on Candida antarctica Lipase Β Adsorption, Distribution, and Polyester Synthesis Activity Downloaded by CORNELL UNIV on October 29, 2016 | http://pubs.acs.org Publication Date: September 19, 2008 | doi: 10.1021/bk-2008-0999.ch010
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Bo Chen , Elizabeth M. Miller , Lisa Miller , John J. Maikner , and Richard A. Gross 1,*
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NSF I/UCRC for Biocatalysis and Bioprocessing of Macromolecules, Polytechnic University, Six Metrotech Center, Brooklyn, NY 11201 Rohm and Haas Company, P.O. Box 904, Spring House, PA 19477 National Synchrotron Light Source, Brookhaven National Laboratory, Upton, NY 11973 2
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Polyacrylic resins were employed to study how immobilization resin particle size influences Candida antarctica Lipase Β ( C A L B ) loading, fraction of active sites, and catalytic properties for polyester synthesis. C A L B adsorbed more rapidly on smaller beads. Saturation occurred in less than 30 seconds and 48 h for beads with diameters 35 and 560-710 μm, respectively. Infrared microspectroscopy showed that C A L B forms protein loading fronts for resins with particle sizes 560-710 and 120 μm while C A L B appears evenly distributed throughout 35 μm resins. The fraction of active C A L B molecules adsorbed onto resins not influenced by particle size was less than 50 %. At about 5% w/w C A L B loading, decrease in the immobilization support diameter from 560-710 to 120, 75 and 35 μm increased conversion of ε-CL to polyester (20 to 36, 42 and 61%, respectively, at 80 min). Similar trends were observed for condensation poly merizations of 1,8-octanediol and adipic acid.
© 2008 American Chemical Society Cheng and Gross; Polymer Biocatalysis and Biomaterials II ACS Symposium Series; American Chemical Society: Washington, DC, 2008.
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Introduction Adsorption is a simple and straightforward route for bioeatalyst immobilization which offers unique advantages over soluble enzymes, such as enhanced activity, increased selectivity, improved stability and reusability. For example, Assemblase, the commercial name of immobilized pencillin-G acylase from E. coli, has been used by industry for manufacture of the semi-synthetic βlactam antibiotic cephalexin. ' Candida antarctica Lipase Β ( C A L B ) is attracting increasing attention as a bioeatalyst for the synthesis of low molar mass and polymeric molecules. " Almost all publications on immobilized C A L B use the commercially available catalyst Novozym® 435, which consists of C A L B physically adsorbed onto a macroporous acrylic polymer resin (Lewatit V P O C 1600, Bayer). Primarily, commercial uses of C A L B are limited to production of high-priced specialty chemicals " because of the high cost of commercially available C A L B preparations: Novozym 435 (Novozymes A/S) and Chirazyme (Roche Molecular Biochemicals). Studies to better correlate enzyme activity to support parameters will lead to improved catalysts that have acceptable price-performance characteristics for an expanded range of industrial processes. Most research on immobilization has focused on choice of matrix materials and optimization of immobilization conditions, " such as hydrophobicity of the support surface ' and p H of the enzyme solution Physical properties of supports also showed significant influence on enzyme loading and catalytic behavior. For example, loading and the specific activity of penicillin-G acylase increased with decreased particle size. Vertegel and Dordick reported that, relative to larger particles, adsorption of lysozyme onto nanoparticles resulted in less loss of lysozyme α-helicity and higher catalytic activity. C A L B , adsorbed onto mesoporous silica, functionalized by octyltriethoxysilane, showed high enzyme loading (200 mg protein/g of silica) and catalytic activity for acylation of ethanolamine with lauric acid. C A L B , adsorbed on octyl-agarose, was highly enantioselective (E=25) for hydrolysis of the R-isomer of chiral R,Smandelic acid esters whereas, the non-immobilized enzyme showed much lower enantioselectivity (E
