- Enzymatic esterification of (-)-menthol with fatty acids in solvent by a commercial lipase from Candida rugosa
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Esterification of (-)-menthol with fatty acids in isooctane was successfully catalyzed using a commercial lipase, Lipase AY 'Amano' 30 from Candida rugosa in original powder form. The esterification reactions were performed to elucidate the effects of temperature, enzyme load, molar ratio of (-)-menthol/fatty acid, and fatty acid type, keeping the (-)-menthol concentration at 200 mM. At the optimal conditions for (-)-menthol esterification, determined at a (-)-menthol/lauric acid molar ratio of 1:1 and 35°C [1.5 g enzyme/g (-)-menthol, 0.1 g molecular sieves], the molar conversion of (-)-menthol after 48 h reached 93%. After 24 h, the lowest and the highest molar conversions of fatty acids at 2:1 molar ratio were obtained with myristic acid (71%) and margaric acid (98%), respectively. After 48 h, the molar conversions of lauric acid at molar ratios 2:1, 1:1, and 1:2 were 98, 93, and 49%, respectively.
- Babali, Banu,Aksoy, H. Ayse,Tueter, Melek,Ustun, Guldem
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- ESSENTIAL OIL DERIVATIVES, THEIR PREPARATION AND USES
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Compounds are described which are derivatives of essential oils, functionalized in order to improve their antibacterial, antiprotozoal and antiviral activity, reduce their volatility and modify their solubility in certain solvents, particularly water. Additionally, also the palatability has been significantly improved with respect to the starting essential oils. These compounds are designed 5 to be used as food ingredients in food products for nutritional purposes and extra-nutritional (as prebiotics) purposes, in both human and animal feed industries, even if these compounds can be successfully used also in cosmetics, detergents and for the control of the microbial load in general.
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Paragraph 0089; 0090; 0091; 0092
(2018/11/02)
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- Heterobimetallic dinuclear lanthanide alkoxide complexes as acid-base difunctional catalysts for transesterification
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A practical lanthanide(III)-catalyzed transesterification of carboxylic esters, weakly reactive carbonates, and much less-reactive ethyl silicate with primary and secondary alcohols was developed. Heterobimetallic dinuclear lanthanide alkoxide complexes [Ln2Na8{(OCH2CH2NMe2)}12(OH)2] (Ln = Nd (I), Sm (II), and Yb (III)) were used as highly active catalysts for this reaction. The mild reaction conditions enabled the transesterification of various substrates to proceed in good to high yield. Efficient activation of transesterification may be endowed by the above complexes as cooperative acid-base difunctional catalysts, which is proposed to be responsible for the higher reactivity in comparison with simple acid/base catalysts.
- Zeng, Ruijie,Sheng, Hongting,Zhang, Yongcang,Feng, Yan,Chen, Zhi,Wang, Junfeng,Chen, Man,Zhu, Manzhou,Guo, Qingxiang
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p. 9246 - 9252
(2014/12/11)
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- Biocatalytic enantiomeric resolution of L-menthol from an eight isomeric menthol mixture through transesterification
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The four diastereomers of menthol and their enantiomers, namely dl-menthol, dl-neomenthol, dl-neoisomenthol and dl-isomenthol, were synthesised by the hydrogenation of thymol to yield an eight isomer liquid menthol. A suitably selective lipase was sought to preferentially esterify l-menthol in organic solvent, hence simplifying separation from the diasteromeric mix through distillation. From an initial screen a commercial Pseudomonas fluorescens lipase (Amano AK) was selected, and vinyl acetate was chosen as a suitable irreversible acyl donor for transesterification. The reaction reagent ratios were optimised, and an enantiomeric excess (ee) of l-menthol of greater than 95% was reproducibly achievable at a conversion of 30% dl-menthol (0.68 M) at ≤50°C. On the basis of the composition of liquid menthol the reaction had a diastereomeric excess (de) of 82%. The enzyme was recycled 150 times in 5 ml batch reactions using liquid menthol and achieving an overall yield of 184.3 g dl-menthol/g commercial enzyme preparation. The by-product acetic acid, formed by hydrolysis of menthyl acetate, was found to cause a high degree of enzyme inactivation. The resolution reaction was scaled up 400 fold to 2 L and the enzyme recycled 38 times with an average conversion of the available l-menthol of 59% and a volumetric productivity of 1.2 g/L/h.
- Brady,Reddy,Mboniswa,Steenkamp,Rousseau,Parkinson,Chaplin,Mitra,Moutlana,Marais,Gardiner
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scheme or table
p. 1 - 10
(2012/03/27)
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- Enzymatic esterification of (-)-menthol with lauric acid in isooctane by sorbitan monostearate-coated lipase from Candida rugosa
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Esterification of (-)-menthol and (±)-menthol with lauric acid in isooctane was successfully catalyzed by a commercial nonionic surfactant (sorbitan monostearate)-coated lipase from Candida rugosa (Lipase AY "Amano" 30) at the molar ratio of 1:1 andat 35°
- Babali,Aksoy,Tuter,Ustun
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p. 173 - 175
(2007/10/03)
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- Thermodynamics of the lipase-catalyzed esterification of 1-dodecanoic acid with (-)-menthol in organic solvents
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The thermodynamics of the lipase-catalyzed stereospecific esterification of 1-dodecanoic acid with (-)- menthol in seven organic solvents have been investigated. Equilibrium measurements were performed using hexane, heptane, cyclohexane, toluene, 2,2,4-trimethylpentane, acetonitrile, and 2-methyl-2-butanol at the temperature T = 298.15 K. The equilibrium constants have been correlated with the (octanol + water) partition coefficients and the relative permittivities of the solvents. The saturation molalities and the (hexane + water) partition coefficients of (-)-menthol, 1-dodecanoic acid, and (-)-menthyl dodecanoate have also been determined at T = 298.15 K. The equilibrium constant of the esterification reaction in aqueous media has been calculated. An important finding is that the molality of water plays an important role in determining the extent of ester formation. In acetonitrile and 2-methyl-2-butanol, which have a very high molality of water, the formation of (-)-methyl dodecanoate is considerably smaller. However, in hydrophobic solvents with lower molalities of water, the formation of (-)-methyl dodecanoate is favored in the reaction mixture. The value of the equilibrium constant varies from 3 to 26. However, the molality of (-)-methyl dodecanoate changes from 0.034 mmol kg-1 in acetonitrile to 16 mmol kg-1 in heptane. The change in product yield is a factor of ≈500 and is a striking example of the utility of organic solvents in biocatalysis.
- Tewari, Yadu B.,Schantz, Michele M.,Vanderah, David J.
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p. 641 - 647
(2007/10/03)
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- Candida Rugosa lipase: Enantioselectivity enhancements in organic solvents
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Chiral resolutions of carboxylic acids (1-3) and alcohol (4) were carried out through esterification or transesterification in organic solvents using cross-linked enzyme crystals (CLEC) of Candida rugosa lipase (CRL). Comparison of these results with those of crude CRL reveal significant differences. As was seen in resolution through hydrolysis, a marked improvement in enantioselectivity is realized with the CLEC. Additionally, the stability afforded the enzyme in CLEC form leads to a higher activity in organic solvent.
- Persichetti, Rose A.,Lalonde, Jim J.,Govardhan, Chandrika P.,Khalaf, Nazer K.,Margolin, Alexey L.
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p. 6507 - 6510
(2007/10/03)
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- Enantioselective Esterification of Racemic Terpene Alcohols with Fatty Acids by Pseudomonas sp. NOF-5 Strain
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The microbial esterification of (+/-)-menthol with various fatty acids by Pseudomonas sp.NOF-5 strain was investigated.A water insoluble fatty acid higher than caproic acid was esterified with (-)-menthol with high enantioselectivity; especially, when lauric acid was used as the fatty acid, the yield of ester was satisfactory.The microbial esterification of various racemic terpene alcohols with lauric acid by the same microorganism was further studied. (-)-Isopulegol and (-)-trans-carveol were esterified from their racemates with high stereoselectivity.However, the esterification of (+/-)-cis-carveol was with poor enantioselectivity, and (+/-)-citronellol was entirely nonselective
- Inagaki, Takashi,Ueda, Hiroo
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p. 1345 - 1348
(2007/10/02)
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- Quantitative Analyses of Biochemical Kinetic Resolution of Enantiomers. 2. Enzyme-Catalyzed Esterification in Water-Organic Solvent Biphasic Systems
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New quantitative expressions, which relate the kinetic and thermodynamic parameters that govern the stereospecificity of enzyme-catalyzed resolution of enantiomers in biphasic aqueous-organic media, have been developed.The theoretical predictions have been verified experimentally, and the technical merit of this esterification methodology has been assessed in relation to the more conventional hydrolytic procedure.
- Chen, Ching-Shih,Wu, Shih-Hsiung,Girdaukas, Gary,Sih, Charles J.
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p. 2812 - 2817
(2007/10/02)
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- LIPASE-CATALYZED ESTER FORMATION IN ORGANIC SOLVENTS. AN EASY PREPARATIVE RESOLUTION OF α-SUBSTITUTED CYCLOHEXANOLS
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The commercial preparation "lipase My" catalyzes ester formation from an alcohol and a fatty acid in organic solvents.Preparative resolution of α-substituted cyclohexanols, including menthol, was achieved under these conditions.
- Langrand, Georges,Secchi, Michel,Buono, Gerard,Baratti, Jacques,Triantaphylides, Christian
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p. 1857 - 1860
(2007/10/02)
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