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Andreas Seidelmorgenstern - One of the best experts on this subject based on the ideXlab platform.
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solid phase behavior in the chiral systems of various 2 hydroxy 2 phenylacetic Acid Mandelic Acid derivatives
Journal of Chemical & Engineering Data, 2015Co-Authors: Jan Langermann Von, Andreas Seidelmorgenstern, Erik Temmel, Heike LorenzAbstract:The solid phase behavior of a series of monosubstituted F-, Cl-, Br-, I-, and CH3- and two 2,4-halogen-disubstituted 2-hydroxy-2-phenylacetic Acid (Mandelic Acid) derivatives was investigated. The study includes detailed information about melting temperature, melting enthalpy, X-ray diffraction data, as well as selected binary phase diagrams of the respective chiral systems. Aside from the known metastable conglomerate 2-chloroMandelic Acid, evidence for two more metastable conglomerates was found.
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solubility of Mandelic Acid enantiomers and their mixtures in three chiral solvents
Journal of Chemical & Engineering Data, 2010Co-Authors: Samuel Kofi Tulashie, Heike Lorenz, Andreas SeidelmorgensternAbstract:A systematic study of the ternary solubility phase diagrams of chiral Mandelic Acid species in the chiral solvents (S)-methyl lactate, (S)-propyl lactate, and (S)-butyl lactate has been carried out. Solubility measurements were performed for different enantiomeric compositions in a temperature range between (273 and 318) K. Experimental results indicated no proof of solubility differences of the enantiomers in all three chiral solvents used. Hence, increasing chain length of the chiral solvents has no influence on chiral recognition. Besides, the eutectic composition in the chiral system in the presence of the solvent as a significant parameter for enantioseparation was determined for all the chiral solvents investigated. Also, the activity coefficients were derived for all three chiral solvents applied.
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solid liquid equilibria of Mandelic Acid enantiomers in two chiral solvents experimental determination and model correlation
Journal of Chemical & Engineering Data, 2010Co-Authors: Samuel Kofi Tulashie, Heike Lorenz, Andreas Seidelmorgenstern, Henning KaemmererAbstract:A study of the ternary solubility phase diagrams of enantiomeric Mandelic Acid species in the chiral solvents (S)-ethyl lactate and (2R,3R)-diethyl tartrate has been carried out. The solubility measurements were conducted for enantiomeric compositions between the racemic compound and the single enantiomer for temperatures between (273 and 333) K. Experimental results showed no evidence of differences in the solubility of both enantiomers in both chiral solvents. The ideal solubility curves of the Mandelic Acid species as well as of the racemic compound revealed large deviations from experimental data. The nonrandom two-liquid (NRTL) model was applied to quantify and parameterize the solid−liquid equilibria (SLE) by means of activity coefficients. Hereby, pronounced solute−solute interactions were found, while solvent−solute interactions were interpreted as being nonchiral specific.
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crystal growth kinetics via isothermal seeded batch crystallization evaluation of measurement techniques and application to Mandelic Acid in water
Industrial & Engineering Chemistry Research, 2005Co-Authors: A Perlberg, Heike Lorenz, Andreas SeidelmorgensternAbstract:Measurements of crystal growth kinetics are often performed by isothermal seeded batch experiments. On the basis of measurements for the chiral system Mandelic Acid/water, this work deals with (a) the experimental evaluation of different analytical techniques to determine simultaneously the solute concentration in the liquid phase and crystal-size-related data and (b) their application to isothermal seeded batch experiments. Calibrations of the applied measurement techniques and the accuracy obtainable are depicted. Metastable zone width measurements are presented, establishing a basis for growth kinetics investigations via isothermal seeded batch experiments. The applicability of the analytical techniques for monitoring isothermal seeded batch experiments is assessed by evaluating measurement results obtained under various experimental conditions. General tendencies with regards to the crystal growth of Mandelic Acid in water are discussed.
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a contribution to the Mandelic Acid phase diagram
Thermochimica Acta, 2004Co-Authors: Heike Lorenz, Andreas SeidelmorgensternAbstract:Literature data on the Mandelic Acid phase diagram are reviewed and examined together with new own results in order to clarify the heterogeneous equilibria in the binary system of the Mandelic Acid enantiomers and the racemate in water. For this purpose the thermal stability and the melting and recrystallization behavior of racemic Mandelic Acid are studied using TG and DSC. A metastable racemic phase is prepared from the melt and solution and identified by means of DSC, XRPD and IR spectroscopy as a monotropic modification of the stable racemic compound. Problems associated with handling the metastable phase are addressed. Finally, a Mandelic Acid phase diagram modified by polymorphy of the racemate is suggested.
Heike Lorenz - One of the best experts on this subject based on the ideXlab platform.
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solid phase behavior in the chiral systems of various 2 hydroxy 2 phenylacetic Acid Mandelic Acid derivatives
Journal of Chemical & Engineering Data, 2015Co-Authors: Jan Langermann Von, Andreas Seidelmorgenstern, Erik Temmel, Heike LorenzAbstract:The solid phase behavior of a series of monosubstituted F-, Cl-, Br-, I-, and CH3- and two 2,4-halogen-disubstituted 2-hydroxy-2-phenylacetic Acid (Mandelic Acid) derivatives was investigated. The study includes detailed information about melting temperature, melting enthalpy, X-ray diffraction data, as well as selected binary phase diagrams of the respective chiral systems. Aside from the known metastable conglomerate 2-chloroMandelic Acid, evidence for two more metastable conglomerates was found.
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Chiral Task-Specific Solvents for Mandelic Acid and Their Impact on Solution Thermodynamics and Crystallization Kinetics
Crystal Growth & Design, 2011Co-Authors: Samuel Kofi Tulashie, Heike Lorenz, Jan Von Langermann, Andreas Seidel-morgensternAbstract:The synthesis and application of enantiopure short-chain Mandelic Acid esters as chiral task-specific solvents were investigated for the determination of hetereochiral interactions between chiral solutes and chiral solvents. Because of specific chiral interactions between the Mandelic Acid enantiomers as solutes and the S-configured solvents for this chiral system, asymmetric behavior was elucidated. Differences for (R)- and (S)-Mandelic Acid were determined with respect to solution thermodynamics and crystallization kinetics for the chiral solvents (S)-Mandelic Acid n-propyl ester [(S)-n-propyl mandelate] and (S)-Mandelic Acid isopropyl ester [(S)-isopropyl mandelate]. These differences were explained via evaluation of enantiospecific interactions applying molecular modeling methods.
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solubility of Mandelic Acid enantiomers and their mixtures in three chiral solvents
Journal of Chemical & Engineering Data, 2010Co-Authors: Samuel Kofi Tulashie, Heike Lorenz, Andreas SeidelmorgensternAbstract:A systematic study of the ternary solubility phase diagrams of chiral Mandelic Acid species in the chiral solvents (S)-methyl lactate, (S)-propyl lactate, and (S)-butyl lactate has been carried out. Solubility measurements were performed for different enantiomeric compositions in a temperature range between (273 and 318) K. Experimental results indicated no proof of solubility differences of the enantiomers in all three chiral solvents used. Hence, increasing chain length of the chiral solvents has no influence on chiral recognition. Besides, the eutectic composition in the chiral system in the presence of the solvent as a significant parameter for enantioseparation was determined for all the chiral solvents investigated. Also, the activity coefficients were derived for all three chiral solvents applied.
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solid liquid equilibria of Mandelic Acid enantiomers in two chiral solvents experimental determination and model correlation
Journal of Chemical & Engineering Data, 2010Co-Authors: Samuel Kofi Tulashie, Heike Lorenz, Andreas Seidelmorgenstern, Henning KaemmererAbstract:A study of the ternary solubility phase diagrams of enantiomeric Mandelic Acid species in the chiral solvents (S)-ethyl lactate and (2R,3R)-diethyl tartrate has been carried out. The solubility measurements were conducted for enantiomeric compositions between the racemic compound and the single enantiomer for temperatures between (273 and 333) K. Experimental results showed no evidence of differences in the solubility of both enantiomers in both chiral solvents. The ideal solubility curves of the Mandelic Acid species as well as of the racemic compound revealed large deviations from experimental data. The nonrandom two-liquid (NRTL) model was applied to quantify and parameterize the solid−liquid equilibria (SLE) by means of activity coefficients. Hereby, pronounced solute−solute interactions were found, while solvent−solute interactions were interpreted as being nonchiral specific.
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Ternary Solubility Phase Diagrams of Mandelic Acid and N-Methylephedrine in Chiral Solvents with Different Carbon Chain Lengths
Crystal Growth & Design, 2010Co-Authors: Samuel Kofi Tulashie, Heike Lorenz, Chandrakant Ramkrishna Malwade, Andreas Seidel-morgensternAbstract:Ternary solubility phase diagrams of Mandelic Acid and N-methylephedrine species in chiral solvents, (S)-methyl lactate, (S)-propyl lactate, and (S)-butyl lactate, have been determined. Solubility measurements were performed for enantiomeric compositions ranging from 50:50 mixtures to the pure enantiomers and temperatures ranging from 0 to 35 °C for Mandelic Acid and from 0 to 25 °C for N-methylephedrine, respectively. The ternary solubility phase diagrams of Mandelic Acid and N-methylephedrine showed symmetric behavior. It became obvious that increasing chain length of chiral solvents, i.e. from (S)-methyl lactate to (S)-butyl lactate, resulted in decreasing solubility. 1HNMR and Raman spectroscopy have been applied to characterize the solute-solvent interaction in the liquid phase for Mandelic Acid system. Molecular modeling calculations were performed for Mandelic Acid to get a deeper understanding of the solute−solvent interactions. The effect of the solvent on the shape of the solubility isotherms is...
Samuel Kofi Tulashie - One of the best experts on this subject based on the ideXlab platform.
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Chiral Task-Specific Solvents for Mandelic Acid and Their Impact on Solution Thermodynamics and Crystallization Kinetics
Crystal Growth & Design, 2011Co-Authors: Samuel Kofi Tulashie, Heike Lorenz, Jan Von Langermann, Andreas Seidel-morgensternAbstract:The synthesis and application of enantiopure short-chain Mandelic Acid esters as chiral task-specific solvents were investigated for the determination of hetereochiral interactions between chiral solutes and chiral solvents. Because of specific chiral interactions between the Mandelic Acid enantiomers as solutes and the S-configured solvents for this chiral system, asymmetric behavior was elucidated. Differences for (R)- and (S)-Mandelic Acid were determined with respect to solution thermodynamics and crystallization kinetics for the chiral solvents (S)-Mandelic Acid n-propyl ester [(S)-n-propyl mandelate] and (S)-Mandelic Acid isopropyl ester [(S)-isopropyl mandelate]. These differences were explained via evaluation of enantiospecific interactions applying molecular modeling methods.
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solubility of Mandelic Acid enantiomers and their mixtures in three chiral solvents
Journal of Chemical & Engineering Data, 2010Co-Authors: Samuel Kofi Tulashie, Heike Lorenz, Andreas SeidelmorgensternAbstract:A systematic study of the ternary solubility phase diagrams of chiral Mandelic Acid species in the chiral solvents (S)-methyl lactate, (S)-propyl lactate, and (S)-butyl lactate has been carried out. Solubility measurements were performed for different enantiomeric compositions in a temperature range between (273 and 318) K. Experimental results indicated no proof of solubility differences of the enantiomers in all three chiral solvents used. Hence, increasing chain length of the chiral solvents has no influence on chiral recognition. Besides, the eutectic composition in the chiral system in the presence of the solvent as a significant parameter for enantioseparation was determined for all the chiral solvents investigated. Also, the activity coefficients were derived for all three chiral solvents applied.
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solid liquid equilibria of Mandelic Acid enantiomers in two chiral solvents experimental determination and model correlation
Journal of Chemical & Engineering Data, 2010Co-Authors: Samuel Kofi Tulashie, Heike Lorenz, Andreas Seidelmorgenstern, Henning KaemmererAbstract:A study of the ternary solubility phase diagrams of enantiomeric Mandelic Acid species in the chiral solvents (S)-ethyl lactate and (2R,3R)-diethyl tartrate has been carried out. The solubility measurements were conducted for enantiomeric compositions between the racemic compound and the single enantiomer for temperatures between (273 and 333) K. Experimental results showed no evidence of differences in the solubility of both enantiomers in both chiral solvents. The ideal solubility curves of the Mandelic Acid species as well as of the racemic compound revealed large deviations from experimental data. The nonrandom two-liquid (NRTL) model was applied to quantify and parameterize the solid−liquid equilibria (SLE) by means of activity coefficients. Hereby, pronounced solute−solute interactions were found, while solvent−solute interactions were interpreted as being nonchiral specific.
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Ternary Solubility Phase Diagrams of Mandelic Acid and N-Methylephedrine in Chiral Solvents with Different Carbon Chain Lengths
Crystal Growth & Design, 2010Co-Authors: Samuel Kofi Tulashie, Heike Lorenz, Chandrakant Ramkrishna Malwade, Andreas Seidel-morgensternAbstract:Ternary solubility phase diagrams of Mandelic Acid and N-methylephedrine species in chiral solvents, (S)-methyl lactate, (S)-propyl lactate, and (S)-butyl lactate, have been determined. Solubility measurements were performed for enantiomeric compositions ranging from 50:50 mixtures to the pure enantiomers and temperatures ranging from 0 to 35 °C for Mandelic Acid and from 0 to 25 °C for N-methylephedrine, respectively. The ternary solubility phase diagrams of Mandelic Acid and N-methylephedrine showed symmetric behavior. It became obvious that increasing chain length of chiral solvents, i.e. from (S)-methyl lactate to (S)-butyl lactate, resulted in decreasing solubility. 1HNMR and Raman spectroscopy have been applied to characterize the solute-solvent interaction in the liquid phase for Mandelic Acid system. Molecular modeling calculations were performed for Mandelic Acid to get a deeper understanding of the solute−solvent interactions. The effect of the solvent on the shape of the solubility isotherms is...
Liming Ouyang - One of the best experts on this subject based on the ideXlab platform.
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cloning and biochemical properties of a highly thermostable and enantioselective nitrilase from alcaligenes sp ecu0401 and its potential for r Mandelic Acid production
Bioprocess and Biosystems Engineering, 2011Co-Authors: Zhijun Zhang, Liming Ouyang, Youyan LiuAbstract:A nitrilase gene from Alcaligenes sp. ECU0401 was cloned and overexpressed in Escherichia coli BL21 (DE3) in a soluble form. The encoded protein with a His6-tag was purified to nearly homogeneity as revealed by SDS-PAGE with a molecular weight of approximately 38.5 kDa, and the holoenzyme was estimated to be composed of 10 subunits of identical size by size exclusion chromatography. The V max and K m parameters were determined to be 27.9 μmol min−1 mg−1 protein and 21.8 mM, respectively, with mandelonitrile as the substrate. The purified enzyme was highly thermostable with a half life of 155 h at 30 °C and 94 h at 40 °C. Racemic mandelonitrile (50 mM) could be enantioselectively hydrolyzed to (R)-(−)-Mandelic Acid by the purified nitrilase with an enantiomeric excess of 97%. The extreme stability, high activity and enantioselectivity of this nitrilase provide a solid base for its practical application in the production of (R)-(−)-Mandelic Acid.
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efficient production of r Mandelic Acid with highly substrate product tolerant and enantioselective nitrilase of recombinant alcaligenes sp
Process Biochemistry, 2010Co-Authors: Zhijun Zhang, Liming Ouyang, Youyan Liu, Tadayuki ImanakaAbstract:Abstract For efficient production of ( R )-(−)-Mandelic Acid, a nitrilase gene from Alcaligenes sp. ECU0401 was cloned and overexpressed in Escherichia coli . After simple optimization of the culture conditions, the biocatalyst production was greatly increased from 500 to 7000 U/l. The recombinant E. coli whole cells showed strong tolerance against a high substrate concentration of up to 200 mM, and the concentration of ( R )-(−)-Mandelic Acid after only 4 h of transformation reached 197 mM with an enantiomeric excess ( ee p ) of 99%. In a fed-batch reaction with 600 mM mandelonitrile as the substrate, the cumulative production of ( R )-(−)-Mandelic Acid after 17.5 h of conversion reached 520 mM. The recombinant E. coli cells could also be repeatedly used in the biotransformation, retaining 40% of the initial activity after 10 batches of reaction. The highly substrate/product tolerable and enantioselective nature of this recombinant nitrilase suggests that it is of great potential for the practical production of optically pure ( R )-(−)-Mandelic Acid.
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Preparation of (R)-(-)-Mandelic Acid and its derivatives from racemates by enantioselective degradation with a newly isolated bacterial strain Alcaligenes sp. ECU0401.
Bioprocess and biosystems engineering, 2007Co-Authors: Jiang Pan, Liming OuyangAbstract:An enantioselective mandelate-degrading bacterium, Alcaligenes sp. ECU0401, was newly isolated from soil. By fed-batch culture, (R)-(−)-Mandelic Acid was successfully prepared in a 5-L fermenter with 32.8% isolated yield and >99.9% enantiomeric excesses (e.e.) from totally 3.04% (w/v) of racemic Mandelic Acid after 99 h of biotransformation. The optimal reaction pH and temperature were 6.5 and 30 °C, respectively. Using the resting cell as a biocatalyst for asymmetric degradation of racemic Mandelic Acid and chloro-substituted derivatives thereof, (R)-(−)-Mandelic Acid, (R)-(−)-o-chloroMandelic Acid, (S)-(+)-m-chloroMandelic Acid and (S)-(+)-p-chloroMandelic Acid were recovered with high analytic yields and excellent enantiomeric excesses (e.e. > 99.9%). (R)-(−)-Mandelic Acid could also be obtained after 12 h of biotransformation with 41.5% isolated yield and >99.9% e.e.
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biocatalytic synthesis of r Mandelic Acid from racemic mandelonitrile by a newly isolated nitrilase producer alcaligenes sp ecu0401
Chinese Chemical Letters, 2007Co-Authors: Liming Ouyang, Jiang PanAbstract:By using acetonitrile as the sole nitrogen source, a microbial strain with high nitrilase activity, named as Alcaligenes sp. ECU0401, was newly isolated from soil, which could enantioselectively transform racemic mandelonitrile into (R)-(-)-Mandelic Acid, with an enantiomeric excess of ＞99.9%.
Zhijun Zhang - One of the best experts on this subject based on the ideXlab platform.
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efficient production of r Mandelic Acid by isopropanol permeabilized recombinant e coli cells expressing alcaligenes sp nitrilase
Biochemical Engineering Journal, 2015Co-Authors: Zhijun Zhang, Tadayuki ImanakaAbstract:Resting cells or immobilized cells are preferentially used as biocatalyst for biocatalytic processes due to the easy preparation and operation, however, the catalytic efficiency of biocatalyst is usually limited by the transport barrier of cell membrane. In this work, the transport barrier of recombinant Escherichia coli cells expressing the nitrilase from Alcaligenes sp. ECU0401 was relieved by isopropanol permeabilization. Under the optimal permeabilization conditions, the nitrilase activity of the permeabilized cells was 4.6-fold that of the cells without permeabilization. The permeabilized cells were evaluated for the enantioselective hydrolysis of mandelonitrile, which showed an initial reaction rate of about 2-fold that of the cells without permeabilization. The permeabilization process did not impair the stability of the cells and after simple immobilization by glutaraldehyde cross-linking, the immobilized permeabilized cells were successfully recycled for 15 runs without significant activity loss, suggesting the potential application of the immobilized permeabilized cells for the production of (R)-(−)-Mandelic Acid. The technology reported in this work might also be extended to other bioprocesses facing cell membrane transport barriers.
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significant enhancement of r Mandelic Acid production by relieving substrate inhibition of recombinant nitrilase in toluene water biphasic system
Journal of Biotechnology, 2011Co-Authors: Zhijun Zhang, Jiang Pan, Junfeng Liu, Youyan LiuAbstract:The enantioselective hydrolysis of mandelonitrile with whole cells of a recombinant Escherichia coli expressing nitrilase activity was severely inhibited by the substrate at high concentrations (>300mM), which resulted in a low yield of the target product (R)-(-)-Mandelic Acid. To relieve the substrate inhibition and to enhance the (R)-(-)-Mandelic Acid productivity, eight water-organic solvent biphasic systems were attempted in this work. Toluene was found to be the most suitable solvent as the organic phase among the solvents tested. Various parameters were systematically examined and optimized in shake flasks. The phase volume ratio, buffer pH and reaction temperature were shown to be sensitive parameters affecting both the yield and the enantiopurity of product in the biphasic system. Under the optimized conditions, significant enhancement of substrate tolerance from 200mM to 500mM and average productivity from 179.6gl(-1)d(-1) to 352.6gl(-1)d(-1) were achieved. Subsequently, the biocatalytic hydrolysis of mandelonitrile was successfully carried out in a stirred reactor (2-l scale) by repeated use of the calcium alginate entrapped cells for 5 batches, affording 110.7g (R)-(-)-Mandelic Acid in 98.0% ee (enantiomeric excess) and a specific production of 13.8g (Mandelic Acid) g(-1) (cell), respectively.
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cloning and biochemical properties of a highly thermostable and enantioselective nitrilase from alcaligenes sp ecu0401 and its potential for r Mandelic Acid production
Bioprocess and Biosystems Engineering, 2011Co-Authors: Zhijun Zhang, Liming Ouyang, Youyan LiuAbstract:A nitrilase gene from Alcaligenes sp. ECU0401 was cloned and overexpressed in Escherichia coli BL21 (DE3) in a soluble form. The encoded protein with a His6-tag was purified to nearly homogeneity as revealed by SDS-PAGE with a molecular weight of approximately 38.5 kDa, and the holoenzyme was estimated to be composed of 10 subunits of identical size by size exclusion chromatography. The V max and K m parameters were determined to be 27.9 μmol min−1 mg−1 protein and 21.8 mM, respectively, with mandelonitrile as the substrate. The purified enzyme was highly thermostable with a half life of 155 h at 30 °C and 94 h at 40 °C. Racemic mandelonitrile (50 mM) could be enantioselectively hydrolyzed to (R)-(−)-Mandelic Acid by the purified nitrilase with an enantiomeric excess of 97%. The extreme stability, high activity and enantioselectivity of this nitrilase provide a solid base for its practical application in the production of (R)-(−)-Mandelic Acid.
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efficient production of r Mandelic Acid with highly substrate product tolerant and enantioselective nitrilase of recombinant alcaligenes sp
Process Biochemistry, 2010Co-Authors: Zhijun Zhang, Liming Ouyang, Youyan Liu, Tadayuki ImanakaAbstract:Abstract For efficient production of ( R )-(−)-Mandelic Acid, a nitrilase gene from Alcaligenes sp. ECU0401 was cloned and overexpressed in Escherichia coli . After simple optimization of the culture conditions, the biocatalyst production was greatly increased from 500 to 7000 U/l. The recombinant E. coli whole cells showed strong tolerance against a high substrate concentration of up to 200 mM, and the concentration of ( R )-(−)-Mandelic Acid after only 4 h of transformation reached 197 mM with an enantiomeric excess ( ee p ) of 99%. In a fed-batch reaction with 600 mM mandelonitrile as the substrate, the cumulative production of ( R )-(−)-Mandelic Acid after 17.5 h of conversion reached 520 mM. The recombinant E. coli cells could also be repeatedly used in the biotransformation, retaining 40% of the initial activity after 10 batches of reaction. The highly substrate/product tolerable and enantioselective nature of this recombinant nitrilase suggests that it is of great potential for the practical production of optically pure ( R )-(−)-Mandelic Acid.