Immobilized lipase-catalyzed

Tbyonife-immobilized lipase-catalyzed resolution of solketal ( )-3 (vinyl butylate)... 

Figure 10 Temperature effect on the rojonite-immobilized lipase-catalyzed resolution of ( )-4 by varying the organic bridges.

A practical resolution of 3-phenyl-2H-azirine-2-methanol 15 at a very low temperature (-40 °C) was reported by Sakai et al64 to enhance the enantioselectivity in immobilized lipase-catalyzed resolution of 15 using vinyl butanoate as acyl donor in ether as organic solvent. The method was found to be effective in enhancing the enantioselectivity E and affords the primary alcohol (S)-15 with 99% ee and the ester (A)-16 with 91% ee. 

Figure 13 Toyonit-immobilized lipase-catalyzed resolution of 1 at -40...

Selmi, B. and Thomas, D. 1998. Immobilized lipase-catalyzed ethanolysis of sunflower oil in a solvent-free medium. J. Am. Oil Chem. Soc., 75, 691-695. 

Hsu, A.-E K. Jones T.A. Foglia W.N. Marmer. Immobilized lipase-catalyzed production of alkyl esters of restaurant grease as biodiesel. Biotechnol. Appl. Biochem. 2002, 36, 181-186. 

During research on enzymatic acylation, Gelo-Pujic et al. [87] performed Novo-zym immobilized lipase-catalyzed esterification of 131a,b and 7 with dodecanoic acid in dry media both with microwave irradiation and with classical heating, using the same conditions of time and temperature (Scheme 12.54). Esterification of 131a by use of a focused Synthewave reactor and oil bath, both at 95 °C, afforded 132 in 95% and 55% yield, respectively. 

Gui-Zhuan X, Bai-Liang Z, Sheng-Yong L, Jian-Zhi Y. 2006. Study on immobilized lipase-catalyzed transesterification of tung oil. Agric Sci China 5 859-864. 

Kang, ST, JS Rhee. (1989). Characteristics of immobilized lipase-catalyzed hydrolysis of olive oil of high concentration in reverse phase system. Biotechnol Bioeng 33 1469-1476. 

Performing a systematic comparison of lipase-catalyzed kinetic resolutions of several seeondaiy aleohols in continuous flow mode (Figure 7) and shake flask batch mode using immobilized and non-mobilized lipases was reported by Csajagi and eo-workers [25]. The results indieated that immobilized as well as lyophilized powder forms of liphases can be effeetively used in eontinuous flow mode kinetie resolutions of raeemic alcohols in non-aqueous solvent systems. The produetivity of the lipases was higher in continuous flow reactors than in batch mode systems, whereas the enantiomer selectivities were similar. 

Similarly, lipase-catalyzed kinetic resolution has also been applied to intermediate nitrile alcohol 46 (Scheme 14.14). Best results were obtained by using immobilized Pseudomonas cepacia (PS-D) in diisopropyl ether, leading to excellent yield and enantiomeric excess of the desired (5)-alcohol 46a, along with (/J)-nitrile ester 47. Reduction of 46a with borane-dimethylsulhde complex, followed by conversion to the corresponding carbamate and subsequent lithium aluminum hydride reduction gave rise to the desired (S)-aminoalcohol intermediate 36, a known precursor of duloxetine (3). 

Scheme 2.2 Enantioselective kinetic resolution of cis/ttoris (IR,5R)-bicyclo[3.2.0]hept-6-ylidene-acetate ethyl ester, 1, catalyzed by immobilized lipase from Candida antarctica (Novozyme 435). The reaction is run in a pH-stat at pH 8.0 and...

Similarly, the esterification of geraniol and citronellol is carried out in hexane and catalyzed by the immobilized lipase Mucor miehei. The geraniol and citronellol esters are extensively used for the fragrance industry, where the use of lipases benefits mild conditions and low impurity side products [14, 15]. 

Internal diffusional limitations are possible any time that a porous immobilized enzymatic preparation is used. Bernard et al. (1992) studied internal diffusional limitations in the esterification of myristic acid with ethanol, catalyzed by immobilized lipase from Mucor miehei (Lipozyme). No internal mass diffusion would exist if there was no change in the initial velocity of the reaction while the enzyme particle size was changed. Bernard found this was not the case, however, and the initial velocity decreased with increasing particle size. This corresponds to an efficiency of reaction decrease from 0.6 to 0.36 for a particle size increase from 180 pm to 480 pm. Using the Thiele modulus, they also determined that for a reaction efficiency of 90% a particle size of 30 pm would be necessary. While Bernard et al. found that their system was limited by internal diffusion, Steytler et al. (1991) found that when they investigated the effect of different sizes of glass bead, 1 mm and 3 mm, no change in reaction rate was observed. 

Due to its structural complexity and interesting physiological activities as an antifungal agent and especially as an immunosuppressive drug, the macrolide rapamycin has been a target of many total syntheses [54-58]. In their approach, Ley and co-workers used a lipase-catalyzed desymmetrization of a meso diol (Fig. 3). In early studies, the selective acetylation of 7W w-2.4-dimethylpentane-1,5-diol was achieved by a PPL immobilized on celite with moderate yields and 92%... 

Moreno, Jose M. Samoza, A. del Campo, Carmen Liama, Emilio F. Sinisterra, Jose V. Organic reactions catalyzed by immobilized lipases. Part I. Hydrolysis of 2-aryl propionic and 2-aryl butyric esters with immobilized Candida cylindracea lipase. J. Mol. Catalysis A Chemical 1995, 95, 179-92. 

We conclude that a commercial immobilized lipase from C. antarctica (Novozym 435) was stable in SCC02 for all experimental conditions investigated. Based on the results obtained here and comparison of them with the results obtained by other investigators, it can be concluded that the magnitude of pressure, temperature, decompression rate, and exposure time needed to inactivate the enzyme strongly depends on the nature and the source of enzyme and, primarily, whether the enzyme is in its native or immobilized form. For the purpose of using this enzyme to catalyze the transesterification reaction of vegetable oils in order to produce esters, the results obtained herein are relevant, because the immobilized lipase can be used with low activity loss at typical conditions of temperature and pressure employed in many biotransformations of raw materials. 

The objective of the present work was to study the synthesis of monolaurin by direct lipase-catalyzed esterification between glycerol and lauric acid without any solvent or surfactant. The effects of lauric acid/ glycerol molar ratio, enzyme concentration, and temperature were studied using an experimental design. The reuse of the commercial immobilized lipase, to reduce the process cost, was also investigated. 

Balcao, V.M., Malcata, F.X. 1998a. On the performance of a hollow-fiber bioreactor for acidolysis catalyzed by immobilized lipase. Biotechnol. Bioeng. 60, 114-123. 

Purified PUFAs can be converted to their ethyl esters by adopting lipase-catalyzed esterification. For example, the ethyl esterification of DHA (Shimada et al., 2001b, 2003d) with an equal mol of EtOH using immobilized C. antarc-... 

Chang et al. (2005) showed the ability of immobilized lipase C. antarctica (Novozym 435) to catalyze the alcoholysis of canola oil and methanol. RSM and a five-level-five-factor CCRD were employed to evaluate the effects of synthesis parameters, such as reaction time, temperature, enzyme concentration, substrate molar ratio of methanol to canola oil, and added water content... 

Kose, O., Tuter, M., and Aksoy, W. A. 2002. Immobilized Candida antarctica lipase-catalyzed alcoholysis of cotton seed oil in a solvent free medium. Bioresour Technol., 83,125-129. 

There is considerable worldwide interest in the application of lipases for fat modification and ester synthesis. In systems with low water activity, lipases are able to catalyze ester synthesis as well as interesterification reactions in fats. The lipase reactions under low water activity can be performed in several ways. We consider batch or continuous reactions in melted fats by use of immobilized lipases as the most relevant way for the industry. 

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