Lipase-catalyzed solvent-free

Hilterhaus, L., Thum, O. and Liese, A. (2008) Reactor concept for lipase-catalyzed solvent-free conversion of highly viscous reactants forming two-phase systems. Organic Process Research Development, 12, 618-625. 

Martinez I, Markovits A, Chamy R et al. (2004) Lipase-catalyzed solvent-free transesterification of wood sterols. Appl Biochem Biotechnol 112 55-62 Matsumoto T, Takahashi S, Kaieda M et al. (2001) Yeast whole-cell biocatalyst constructed by intracellular overproduction of Rhizopus oryzae lipase is applicable to biodiesel fuel production. Appl Microbiol Biotechnol 57(4) 515-520 Maurer K (2004) Detergent proteases. Curr Opin Biotechnol 15 330-334... 

Lipase-catalyzed solvent-free kinetic resolution of substituted racemic e-caprolactones... 

Selmi, B., Gontier, E., Ergan, F., and Thomas, D. (1998) Effects of fatty acid chain length and unsaturation number on triglyceride synthesis catalyzed by immobilized lipase in solvent-free medium. Enzyme Microb. Technd., 23, 182-186. 

Enzymatic enantioselectivity in organic solvents can be markedly enhanced by temporarily enlarging the substrate via salt formation (Ke, 1999). In addition to its size, the stereochemistry of the counterion can greatly affect the enantioselectivity enhancement (Shin, 2000). In the Pseudomonas cepacia lipase-catalyzed propanolysis of phenylalanine methyl ester (Phe-OMe) in anhydrous acetonitrile, the E value of 5.8 doubled when the Phe-OMe/(S)-mandelate salt was used as a substrate instead of the free ester, and rose sevenfold with (K)-maridelic acid as a Briansted-Lewis acid. Similar effects were observed with other bulky, but not with petite, counterions. The greatest enhancement was afforded by 10-camphorsulfonic acid the E value increased to 18 2 for a salt with its K-enanliomer and jumped to 53 4 for the S. These effects, also observed in other solvents, were explained by means of structure-based molecular modeling of the lipase-bound transition states of the substrate enantiomers and their diastereomeric salts. 

The resolution of (7i,. S )-naproxen 54 using lipase-catalyzed esterification of the free acid with different diols and organic solvents was reported. The (.S)-naproxcn ester 55 was obtained in > 99 % ee when using 1,4-butandiol.79... 

The latter two successful processes were combined in the solvent-free lipase-catalyzed reaction of 1-O-ethyl glucoside with trimethylene carbonate or -caprolactone to form amphiphilic oligomers and polymers [20]. The products are biodegradable polycarbonates and polyesters that are formed regioselectively by reaction with the primary hydroxyl group of the sugar moiety. 

Lipase catalyzed esterifications were performed favorably solvent-free [21] and were applied also to bulk polymerization for polyester synthesis [22]. 

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. 

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. 

Lipase-selective esterification has recently helped fractionate PUFA species present in the same mixture. Fish oil-derived FFA was esterified with glycerol using Lipozyme IM in solvent-free media to fractionate DHA and EPA. The unesterified FFA contained 78%o DHA and only 3% EPA, with a 79%o recovery of DHA the esters contained the majority of the EPA and the other acyl groups, with a 91%o recovery of EPA.f Lipases have also successfully fractionated the two most abundant species of CLAs 18 2-9c,llt and 18 2-10t,12c from an equimolar mixture derived from acid-catalyzed isomerization of ALA. ° ... 

Lozano P, Piamtongkam R, Kohns K, de Diego T, Vaultier M, Iborra JL (2007) Ionic liquids improve dtroneUyl ester synthesis catalyzed by immobilized Candida antarctica lipase B in solvent-free media. Green Chem 9 780-784... 

FIGURE 8.4 Effect of solvent removal and the stepwise addition of fructose on the percent conversion of saccharide (a) and on the solubility of fructose (b) for lipase-catalyzed fructose-oleic acid esterification. ( ) Fructose was added to 50 mmol oleic acid and 13.4 g tert-butanol in 5 mmol increments for 2-h cycles until the net amount of fructose added was 25 mmol tert-butanol underwent free evaporation for up to 10 h, at which time, the reaction was stopped, solvent was removed completely by rotary evaporation, then the reaction was continued. (A) Fructose (25 mmol) was added at time 0 to 50 mmol of oleic acid and 13.4 g (46.9 wt.% fructose-free basis) tert-butanol solvent freely evaporated away throughout at a rate of 0.47 g per h. Both reactions were operated in stirred batch mode using approximately 0.5 g immobilized C. antarctica lipase, (Chirazyme L-2, s.-f, c2, Lyo., Boehringer-Mannheim, Indianapolis, IN), a stir rate of 450 rev min and a reaction temperature of 65°C. (From Walde, P. et al., Chem. Phys. Lipids, 53, 265-288, 1990. With permission.)... 

Uyama, H., Inaka, K., and Kobayashi, S. (2000) Lipase-catalyzed synthesis of aliphatic polyesters by polycondensation of dicarboxylic acids and glycols in solvent-free system. Polym. J., 32 (5), 440-443. 

Li, G., Yao, D., and Zong, M. (2008) Lipase-catalyzed synthesis of biodegradable copolymer containing malic acid units in solvent-free system. Eur. Polym.J., 44 (4), 1123-1129. 

Monoglycerides and Diglycerides Synthesis in a Solvent-Free System by Lipase-Catalyzed Glycerolysis... 

Lipase-catalyzed glycerolysis of oils and fats using solvent-free system at atmospheric pressure and lower temperature have attracted interest in both academic and industrial fields. Because of the possibility of further separation of the reaction products by vacuum distillation, lower energy requirements, selectivity of the enzymes [13], and possibility of recoverability and recyclability of immobilized enzymes [14], it is believed to be a practical alternative method for MG and DG production. 

In this work, MG and DG are produced through lipase-catalyzed glycerolysis of soybean oil in a batch reactor using Candida antarctica B, Thermomyces lanuginosus, Rhizomucor miehei, Candida rugosa, and Aspergillus niger lipases, in a solvent-free system. 

In the solvent-free system utilized herein, involving the following reaction conditions 5% (w/w) Novozym, 3 1 methanol/oil molar ratio, 260rpm rotary shaker speed, and 40 °C, the conversion was found to be extremely low (only 1.8% at 24h), owing principally to the toxicity of excessive methanol on lipase activity and the difficulty of mixing, whereas the conversion (70.9% at 24h) was increased as the result of the addition of tert-butanol as a reaction solvent into the reaction mixture (data not shown). This has been explained as reported previously by Li et al. [12] that the presence of terf-butanol could improve the solubility of methanol in the reaction mixture, and thus lipase retained a high level of activity with all methanol added for lipase-catalyzed methanolysis. 

In nature, hydrolases are used to degrade or hydrolyze particular functionalities, e.g., lipases to hydrolyze esters and proteases to hydrolyze peptide (amide) linkages (J). It is well known that under suitable reaction conditions lipase can catalyze reverse reactions to form polyesters 4,5). Some of these methods have relied upon the use of organic solvents, whereas others are solvent-free processes. However, it is not previously known that proteases can catalyze reverse reactions to form amide polymers. 

Based on their work on supercritical CO2 (see also Scheme 23), Reetz and Leitner introduced a technologically new and interesting continuous flow process for enzymatic reactions [65]. The group designed a protocol for enzymatic reactions, namely the lipase-catalyzed acylation (CAL B) of octan-1 -ol by vinyl acetate in ionic liquids (l-butyl-3-methylimidazolium bis(trifluo-romethanesulfonimide) [BMIM] [BTA]) using supercritical CO2 as the mobile phase (Scheme 25). The alcohol is pumped through the biphasic system and the products are obtained in solvent-free form in a cold trap. The enzyme/ionic liquid mixture can be recycled in batchwise or continuous flow operations. 

Enzymes have been used for biocatalysis in organic solvents since the early 1980s, and in ILs since 2000 [17]. As biological catalysts, enzymes accelerate reactions but do not affect the equilibrium distribution. Hence, hydrolytic enzymes that, as an example, under normal circumstances in aqueous solutions hydrolyze esters and amides, will, when placed in water-free conditions, also catalyze the reverse reaction, the condensation of an acid with an alcohol or an amine, to give esters and amides, respectively. Further, under water-free conditions hydrolytic enzymes can accept alternative nucleophiles to catalyze reactions such as transesterifications. An important industrial example of this is the lipase-catalyzed transesterification of triglycerides to obtain fats with a desired melting point [18]. 

Some enzymes have been found to function in essentially water-free systems. For instance, Klibanov [1] showed that both pancreatic and microbial lipases catalyze transesterification in nearly anhydrous organic solvents. However, it seems that the majority of enzymes lose their activity more rapidly in water-free systems than in media containing a small amount of water. The interest in microemuisions as reaction media stems from the fact that in such systems the amount of water in the formulation can be varied almost... 

Biocatalytic transformation of glycerol has been accomplished via a lipase-catalyzed process using tetrahydrofuran as solvent, [85] but solvent-free conditions using dimethyl carbonate in excess may be also efficient... 

Zhong, H Fang, Z Zou, B Li, X Ouyang, P Guo, K. Studies on the lipase-catalyzed esterification of alkyl-oleates in solvent-free systems. Journal of Molecular Catalysis B Enzymatic, 2013, v. 90, 114-117. 

The Mitsunobu esterification was the first inversion of configuration applied together with the lipase-catalyzed acylation of secondary alcohols (38). Another possibility is shown in Figure 23. The CAL-B-catalyzed kinetic resolution of ethyl-3-hydroxybutanoate by acylation with vinyl acetate has been discussed already in Figure 4 (9). Normal kinetic resolution under the solvent-free conditions by... 

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