Statistical optimization of lipase catalyzed enantioselective production of 1-phenyl 1-propanol by response surface methodology
Integration of life sciences & engineering
Integration of Life Sciences & Engineering - Poster (T5-P)
Keywords: Enantioselectivity, 1-phenyl 1-propanol, kinetic resolution, response surface methodology
The different forms of enantiomeric products can cause quite different biological effects. Chiral drugs, agrochemicals, food additives and fragrances classes of compounds with high economic and scientific potential. Therefore, during the last decade there has been an increased interest in using enzymes for asymmetric synthesis and kinetic resolution to obtain pure enantiomers (Persson et al 2002, Frings et al 1999). Lipases usually successfully resolve chiral secondary alcohols. Lipase activity and selectivity are strongly influenced by the medium used for desired reaction (Theil 2000).
In this study, the effect of the reaction conditions on the enantioselective transesterification of 1-phenyl 1-propanol catalyzed by Novozyme 435 has been investigated. Izooktan and vinyl laurate have been identified as the best solvent and acyl donor, respectively. Optimization of reaction condition for maximization of enantioselective production of 1-phenyl 1-propanol was studied using response surface methodology (RSM).
Conventional methods of optimization, changing one parameter at a time and keeping the other parameters constant are the time consuming methods and do not give information of the mutual interaction. Statistical methods provide an alternative methodology to optimize a particular process by considering mutual interactions among the variables and give and estimate of the combined effect of these variables on final result (Murthy et al 2000).
The substrate concentration (8.34-325 mM), molar ratio of acyl donor to substrate (0.8-3.2), amount of enzyme (40-160 mg), temperature (16-64oC) and stirring rate (31-270 rpm) were the critical components of the reaction condition optimized. Experiments were carried out in 10 ml closed vessel with 3 ml working volume. The response surface equation to predict enantiomeric excess in above range of critical component is
y=71.41+7.93x1-1.37x2-2.21x3+3.22x4+0.80x5-8.69xı2+0.065x22-3.03x32-5.77x42-4.71 x52-7.19x1x2+5.91x1x3+4.55x1x4+2.09x1x5-1.47x2x3+0.66x2x4-0.78x2x5-1.78x3x4-1.84 x3x5-0.84x4x5 (1)
Where Y is the response, (ee %). x1, x2, x3 x4 and x5 are codded value of the critical component as mentioned above, respectively. Maximum Y (91%) was obtained by employing the optimum reaction conditions which were obtained by solving Eq. (1) using Microsoft Excell Software; a substrate concentration of 323 mM, a molar ratio of acyl donor to substrate of 0.8, amount of enzyme of 156 mg, temperature of 47oC and stirring rate of 166 rpm.
Keywords: Enantioselectivity, 1-phenyl 1-propanol, kinetic resolution, response surface methodology
References
Frings, K., Koch M., Hartmeier, W., Kinetics Resolution Of 1-phenyl ethanol with high enantioselectivity with native and immobilized lipase in organic solvents, Enzyme and Microbial Technology, 1999;25:303-309.
Murthy MSRC, Swaminathan SK, Rakshit SK and Kosugi Y. Statistical optimization of lipase catalyzed hydrolysis of methyloleate by response surface methodology. Bioprocess Eng 2000;22:35-39.
Theil, F. Enhancement of selectivity of reactinity of lipases by additives, Tetrahedron 56(2000)2905-2919.
Persson M., Costes D., Wehtje E. and Adlercreutz P., Effect of solvent, water activity and temperature on lipase and hydroxynitrile lyse enantioselectivity. Enzyme and Microbial Technology, 2002;30:916-923.
Acknowledgements
This work was supported by Biotechnology Institute (Project no:2001K120140-162).
Presented Wednesday 19, 13:30 to 15:00, in session Integration of Life Sciences & Engineering - Poster (T5-P).
