Abstract
On-line conversion estimation of enzymatic esterification reactions in solvent-free media was investigated. In principle, conversion to ester can be determined from the amount of water produced by the reaction, because water is formed as a by-product in a stoichiometric manner. In this study, we estimated the water production rate only from some measurements of relative humidity and water balances without using any analytical methods. In order to test the performance of the on-line conversion estimation, the lipase-catalyzed esterification ofn-capric acid andn-decyl alcohol in solvent-free media was performed whilst controlling water activity at various values. The reaction conversions estimated on-line were similar to those determined by offline gas chromatographic analysis. However, when the water activity was controlled at higher values, discrepancies between the estimated conversion values and the measured values became significant. The deviation was found to be due to the inaccurate measurement of the water content in the reaction medium during the initial stages of the reaction. Using a digital filter, we were able to improve the accuracy of the on-line conversion estimation method considerably. Despite the simplicity of this method, the on-line estimated conversions were in good agreement with the off-line measured values.
Similar content being viewed by others
References
Klibanov, A. M. (2001) Improving enzymes by using them in organic solvents.Nature 409: 241–246.
Zaks, A. (2001) Industrial biocatalysis.Curr. Op. Chem. Biol. 5: 130–136.
Danielsson, B. and L. Flygare (1989) Biothermal analysis performed in organic solvents.Anal. Lett. 22: 1417–1428.
Stasinska, B., B. Danielsson, and K. Mosbach (1989) The use of biosensors in organic synthesis: peptide synthesis by immobilized α-chymotrypsin assessed with an enzyme thermistor.Biotechnol. Tech. 3: 281–288.
Lammers, F. and T. Scheper (1997) On-line monitoring of enzyme-catalyzed biotransformations with biosensors.Enzyme Microb. Technol. 20: 432–436.
Sarazin, C., F. Ergan, J.-P. Séguin, G. Goethals, M.-D. Legoy and J.-N. Barbotin (1996) NMR on-line monitoring of esterification catalyzed by cutinase.Biotechnol. Bioeng. 51: 636–644.
Brecker, L. and D. W. Ribbons (2000) Biotransformations monitoredin situ by proton nuclear magnetic resonance spectroscopy.Trends Biotechnol. 18: 197–202.
Weber, H. and L. Brecker (2000) Online NMR for minitoring biocatalysed reactions.Curr. Op. Biotechnol. 11: 572–578.
Wang, H. Y., C. L. Cooney, and D. I. C. Wang (1977) Computer-aided baker's yeast fermentations.Biotechnol. Bioeng. 19: 69–86.
Zabriskie, D. W. and A. E. Humphrey (1978) Real-time estimation of aerobic batch fermentation biomass concentration by component balancing.AIChE J. 24: 138–146.
Constantinides, A. and P. Shao (1981) Material balancing applied to the prediction of glutamic acid production and cell mass formation.Ann. NY Acad. Sci. 369: 167–180.
Liao, J. C. (1989) Fermentation data-analysis and state estimation in the presence of incomplete mass balance.Biotechnol. Bioeng. 33: 613–622.
Xiu, Z.-L., W.-D. Deckwer, and A.-P. Zeng (1999) Estimation of rates of oxygen uptake and carbon dioxide evolution of animal cell culture using material and energy balances.Cytotechnology 29: 159–166.
Kim, J. E., J. J. Han, J. H. Yoon, and J. S. Rhee (1998) Effect of salt hydrate pair on lipase-catalyzed regioselective monoacylation of sucrose.Biotechnol. Bioeng. 57: 121–125.
Pepin, P. and R. Lortie (1999) Influence of water activity on the enantioselective esterification of(R,S)-ibuprofen byCandida amarctica lipase B in solventless media.Biotechnol. Bioeng. 63: 502–505.
Wehtje, E., D. Costes, and P. Adlercreutz (1999) Continuous lipase-catalyzed production of wax ester using silicone tubing.J. Am. Oil Chem. Soc. 76: 1489–1493.
Won, K. and S. B. Lee (2001) Computer-aided control of water activity for lipase-catalyzed esterification in solvent-free systems.Biotechnol. Prog. 17: 258–264.
Condoret, J.-S., S. Vankan, X. Joulia, and A. Marty (1997) Prediction of water adsorption curves for heterogeneous biocatalysis in organic and supercritical solvents.Chem. Eng. Sci. 52: 213–220.
Han, J. J. and T. Yamane (1999) Enhancement of both reaction yield and rate of synthesis of structured triacylglycerol containing eicosapentaenoic acid under vacuum with water activity control.Lipids 34: 989–995.
McMinn, J. H., M. J. Sowa, S. B. Charnick, and M. E. Paulaitis (1993) The hydration of protein in nearly anhydrous organic solvent suspensions.Biopolymers 33: 1213–1224.
Yang, F. and A. J. Russell (1996) The role of hydration in enzyme activity and stability: 1. water adsorption by alcohol dehydrogenase in a continous gas phase reactor.Biotechnol. Bioeng. 49: 700–708.
Brunauer, S., P. H. Emmett, and E. Teller (1938) Adsorption of gases in multimolecular layers.J. Am. Chem. Soc. 60: 309–319.
Lee, S. B. and K.-J. Kim (1995) Effect of water activity on enzyme hydration and enzyme reaction rate in organic solvents.J. Ferment. Bioeng. 79: 473–478.
Arroyo, M., J. M. Sanchez-Montero, and J. V. Sinisterra (1996) A new method to determine thea w range in which immobilized lipases display optimum activity in organic media.Biotechnol. Tech. 10: 263–266.
De la Casa, R. M., J. M. Sanchez-Montero, and J. V. Sinisterra (1996) Water adsorption isotherm, as a tool to predict the preequilibrium water amount in preparative esterification.Biotechnol. Lett. 18: 13–18.
Lim, H. C. and K. S. Lee (1992) Process control and optimization. In: Pons MN. Bioprocess monitoring and control. München: Hanser Publishers. p. 159–222.
Seborg, D. E., T. F. Edgar, and D. A. Mellichamp (1989)Process Dynamics and Control. John Wiley & Sons, Singapore.
Oisiovici, R. M., S. L. Cruz, and J. A. F. R. Pereira (1999) Digital filtering in the control of a batch distillation columm.ISA Trans. 38: 217–224.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Won, K., Lee, S.B. On-line conversion estimation for solvent-free enzymatic esterification systems with water activity control. Biotechnol. Bioprocess Eng. 7, 76–84 (2002). https://doi.org/10.1007/BF02935883
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF02935883