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Immobilized Lipase (immobilized + lipase)
Selected AbstractsCharacteristics of Immobilized Lipase on Hydrophobic Superparamagnetic Microspheres To Catalyze EsterificationBIOTECHNOLOGY PROGRESS, Issue 2 2004Zheng Guo A novel immobilized lipase (from Candida rugosa) on hydrophobic and superparamagnetic microspheres was prepared and used as a biocatalyst to catalyze esterification reactions in diverse solvents and reaction systems. The results showed that the immobilized lipase had over 2-fold higher activities in higher log P value solvents. An exponential increase of lipase activity against log P of two miscible solvent mixtures was observed for the first time. Both free and immobilized lipase achieved its maximum activity at the range of water activity ( aw) 0.5,0.8 or higher. At aw 0.6, the immobilized lipase exhibited markedly higher activities in heptane and a solvent-free system than did the native lipase. In multicompetitive reactions, the alcohol specificity of the lipase showed a strong chain-length dependency, and the immobilized enzyme exhibited more preference for a longer-chain alcohol, which is different from previous reports. The immobilized lipase showed higher specificities for butyric acid and the medium-chain-length fatty acids (C8,C12). Then, the immobilized lipase was extended to solvent-free synthesis of glycerides from glycerol and fatty acids. Recovered by magnetic separation, the immobilized lipase exhibited good reusability in repeated batch reaction, indicating its promising feature for biotechnology application. [source] Esterification of n -butyric acid with n -butyl alcohol and transesterification of (R,,S)-phenylethanol by lipase immobilized on cellulose acetate,TiO2 gel fibreJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2002Yuko Ikeda Abstract Lipase (EC 3.1.1.3) was immobilized on cellulose acetate,TiO2 gel fibre by the sol,gel method. The immobilized lipases were used for esterification of n -butyric acid with n -butyl alcohol and enantioselective acylation of (R, S)-phenylethanol using vinyl acetate as an acyl donor. Compared with native lipase, the activity of the immobilized lipase was stable and relatively unaffected by the water content of the solvent and the substrate concentration. The data indicate that the lipases are immobilized on the fibre surface and that enzyme activity is influenced by bound water. However, the thermal reactivity and enantioselectivity of the immobilized lipase were less than those of native lipase. This may not reflect thermal inactivation of the enzyme but rather significant thermal contraction of the gel fibre by cellulose crystallization, resulting in liberation of bound water and a decrease in the amount of enzyme which is available for the reaction. Copyright © 2001 Society of Chemical Industry [source] Architecture and performance of mesoporous silica-lipase hybrids via non-covalent interfacial adsorptionAICHE JOURNAL, Issue 2 2010Shan Lu Abstract To investigate the effects of surface property of mesoporous supports on the lipase immobilization and the performance of immobilized lipase, the mesoporous molecular sieve SBA-15 is functionalized with three organic moieties, dimethyl (DM), diisopropyl (DIP), and diisobutyl (DIB), respectively, by post-synthesis grafting and one-pot synthesis methods. Porcine pancreas lipase (PPL) is immobilized on SBA-15 supports through hydrogen bonding and hydrophobic interaction. The hydrophobic adsorption involves no active sites of PPL, and neither hyper-activation nor total inactivation occurs. The study on the intrinsic stability of PPL, including thermal stability, pH stability, and storage stability, indicates that the entrapment in mesoporous supports, and especially in organic-functionalized supports, makes PPL more resistant to temperature increment but more sensitive to pH change. The reusability investigation shows that the organic modification of mesoporous surface inhibits the enzyme leaching to some extent, resulting in a better operational stability. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Thermodynamic activity-based enzyme kinetics: Efficient tool for nonaqueous enzymologyAICHE JOURNAL, Issue 3 2001Georgina C. Sandoval Lipase-catalyzed synthesis reactions must be performed in nonaqueous media (organic solvents or solvent-free systems). The choice of the optimal solvent is usually a fastidious task that necessitates the determination of kinetic parameters in each solvent. The approach used here, to overcome the lack of a model that can predict the kinetics whatever the solvent, consists in the use of thermodynamic activities instead of concentrations of components, and assumes that activity-based kinetic parameters are the same in all solvents. This assumption is discussed, and a solution is proposed which takes into account some observed residual solvent effects. The reaction chosen to test this approach was the esterification of oleic acid with ethanol catalyzed by an immobilized lipase, Lipozyme. For this reaction, the kinetics predicted in various organic solvents and in solvent-free systems is in agreement with the experimental data. [source] Electrospun Nanofibers Modified with Phospholipid Moieties for Enzyme ImmobilizationMACROMOLECULAR RAPID COMMUNICATIONS, Issue 16 2006Xiao-Jun Huang Abstract Summary: PANCMPCs containing phospholipid side moieties were electrospun into nanofibers with a mean diameter of 90 nm. Field emission SEM was used to characterize the morphologies of the nanofibers. These phospholipid-modified nanofibers were explored as supports for enzyme immobilization due to the characteristics of excellent biocompatibility, high surface/volume ratio, and porosity, which were beneficial to the catalytic efficiency and activity of immobilized enzymes. Lipase from Candida rugosa was immobilized on these nanofibers by adsorption. Preliminary results indicated that the properties of the immobilized lipase on these phospholipid-modified nanofibers were greatly promising. Schematic representation of the structure and electrostatic properties of phospholipid-modified nanofibers. [source] Characteristics of Immobilized Lipase on Hydrophobic Superparamagnetic Microspheres To Catalyze EsterificationBIOTECHNOLOGY PROGRESS, Issue 2 2004Zheng Guo A novel immobilized lipase (from Candida rugosa) on hydrophobic and superparamagnetic microspheres was prepared and used as a biocatalyst to catalyze esterification reactions in diverse solvents and reaction systems. The results showed that the immobilized lipase had over 2-fold higher activities in higher log P value solvents. An exponential increase of lipase activity against log P of two miscible solvent mixtures was observed for the first time. Both free and immobilized lipase achieved its maximum activity at the range of water activity ( aw) 0.5,0.8 or higher. At aw 0.6, the immobilized lipase exhibited markedly higher activities in heptane and a solvent-free system than did the native lipase. In multicompetitive reactions, the alcohol specificity of the lipase showed a strong chain-length dependency, and the immobilized enzyme exhibited more preference for a longer-chain alcohol, which is different from previous reports. The immobilized lipase showed higher specificities for butyric acid and the medium-chain-length fatty acids (C8,C12). Then, the immobilized lipase was extended to solvent-free synthesis of glycerides from glycerol and fatty acids. Recovered by magnetic separation, the immobilized lipase exhibited good reusability in repeated batch reaction, indicating its promising feature for biotechnology application. [source] Synthesis of Water-Soluble Retinol Derivatives by Enzymatic MethodBIOTECHNOLOGY PROGRESS, Issue 3 2002Thierry Maugard Retinoids (vitamin A and derivatives) are of great commercial potential in cosmetics and pharmaceuticals such as skin care products. However, the clinical effectiveness of these retinoids is limited by skin irritation, water insolubility, and except for retinyl-esters, extreme instability. In this paper, an enzymatic method for preparing water-soluble retinol derivatives catalyzed by immobilized lipase is described. The synthesis is based on a unique strategy of two-step enzymatic acylation. Among the different synthesized compounds, the most water-soluble are the disaccharide derivatives such as saccharose retinyl adipate (nonionic water-soluble retinol derivative) and the sodium salt of retinyl diacids such as retinyl succinate sodium salt (ionic water-soluble retinol derivative). [source] Lipase-catalyzed production of biodiesel from rice bran oilJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 3 2005Chao-Chin Lai Abstract Biodiesel has attracted considerable attention as an alternative fuel during the past decades. The main hurdle to the commercialization of biodiesel is the cost of the raw material. Use of an inexpensive raw material such as rice bran oil is an attractive option to lower the cost of biodiesel. Two commercially available immobilized lipases, Novozym 435 and IM 60, were employed as catalyst for the reaction of rice bran oil and methanol. Novozym 435 was found to be more effective in catalyzing the methanolysis of rice bran oil. Methanolysis of refined rice bran oil and fatty acids (derived from rice bran oil) catalyzed by Novozym 435 (5% based on oil weight) can reach a conversion of over 98% in 6 h and 1 h, respectively. Methanolysis of rice bran oil with a free fatty acid content higher than 18% resulted in lower conversions (<68%). A two-step lipase-catalyzed methanolysis of rice bran oil was developed for the efficient conversion of both free fatty acid and acylglycerides into fatty acid methyl ester. More than 98% conversion can be obtained in 4,6 h depending on the relative proportion of free fatty acid and acylglycerides in the rice bran oil. Inactivation of lipase by phospholipids and other minor components was observed during the methanolysis of crude rice bran oil. Simultaneous dewaxing/degumming proved to be efficient in removing phospholipids and other minor components that inhibit lipase activity from crude rice bran oil. Copyright © 2005 Society of Chemical Industry [source] Olive husk oil transesterification in a fluidized bed reactor with immobilized lipasesASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2009Emanuele Ricca Abstract In the present work, olive husk oil was continuously transesterified by immobilized lipases in a fluidized bed reactor (FBR). Preliminary fluidization tests were run to find the fluidization flow rate for the system under study. Subsequently, the reactor was operated continuously performing high productivity, as compared to literature data on packed bed reactors (PBR) for biodiesel production and to batch data reported in this work. The system was also run in a recycle configuration aiming at studying the effect of repeated passages of the substrates within the reactor, without changing fluidization conditions (i.e. decreasing the fresh feed flow rate to the system by increasing the recycle flow rate, without changing the flow rate entering the reactor). Tests at different recycle ratios were performed to investigate the effect on the process performance of different dilution degrees within the reactor and fresh flow rates fed to the system and to find optimal operating conditions. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] | ||||||||||