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Papers by Miguel Angel Gonzales Arroyo

Research paper thumbnail of Thermal stabilization of immobilized lipase B from Candida antarctica on different supports: Effect of water activity on enzymatic activity in organic media

Enzyme and Microbial Technology, 1999

Covalent immobilization of C. antarctica lipase B (CALB) on sepharose, alumina, and silica was un... more Covalent immobilization of C. antarctica lipase B (CALB) on sepharose, alumina, and silica was undertaken. The thermal stability of these covalently immobilized catalysts were studied and compared to adsorbed derivatives from Novo Nordisk at 50°C under wet conditions. Native enzyme and Novozym 435 follow a deactivation model E 3 E 1 whereas covalently immobilized derivatives and SP435A follow the model E 3 E 1 3 E 2. This different behavior is related to the nature of the support and the immobilization methodology. Water absorption isotherms of dry solid biocatalysts in air or isooctane were used to predict the optimum preequilibrium a w value to obtain the highest rate in the esterification of (r,s)-ibuprofen.

Research paper thumbnail of Covalent immobilization of pure isoenzymes from lipase of Candida rugosa

Enzyme and Microbial Technology, 1997

Covalent irnmobilizution of pure lipases A and B from Candida rugosa on agarose and silica is des... more Covalent irnmobilizution of pure lipases A and B from Candida rugosa on agarose and silica is described. The immobilization increases the half-life of the biocatalysts (tx. = 5 h) with respect to the native pure lipases (tl,? = 0.28 h). The percentage immobilization of lipases A and B is similar in both supports (33-40%). The remaining activity of the biocatalysts immobilized on agarose (70-75%) is greater than that of the enzymatic derivatives immobilized on SiO, (40-50%). The surjixce area and the hydrophobic/hydrophilic properties of the support control the lipase activiw of these derivatives. The thermal stability of the immobilized lipase A derivatives is greater than that of lipase B derivatives. The nature of the support influences the thermal deactivation profile of the immobilized derivatives. The immobilization in agarose (hydrophilic support) gives biocatalysts that show a greater initial specific reaction rate than the biocatalysts immobilized in Si02 (hydrophobic support) using the hydrolysis of the esters of(R) or(S) 2-chloropropanoic and of (R,S) 2-phenylpropanoic acids as the reaction test. The enzymatic derivatives are active for at least 196 h under hydrolysis conditions. The stereospecifi+v of the native and the immobilized enzymes is the same.

Research paper thumbnail of A new method to determine the aw range in which immobilized lipases display optimum activity in organic media

Biotechnology Techniques, 1996

... 199, 609-614. Arroyo, M.; Moreno, JM and Sitisterra, JV (1995) J. Mol. Catal. A: Chem. 97, 19... more ... 199, 609-614. Arroyo, M.; Moreno, JM and Sitisterra, JV (1995) J. Mol. Catal. A: Chem. 97, 195-201. De la Casa, RM; Stichez-Montero, JM and Sinisterra, JV (1996) Biotech. Lett. 18, 13-18. Norin, M.; Boutelje, J.; Holmberg, E. and Hult, K. (1988) Appl. Microbial. Biotechnol. ...

Research paper thumbnail of Influence of chiral carvones on selectivity of pure lipase-B from Candida antarctica

Biotechnology Letters, 1995

ABSTRACT In the esterification reaction in non-aqueous media lipase-B from Candida antarctica is ... more ABSTRACT In the esterification reaction in non-aqueous media lipase-B from Candida antarctica is stereoselective towards the R-isomer of ketoprofen in an achiral solvent such as isobutyl methyl ketone and in S(+) carvone. On the contrary, S(+) ketroprofen is esterified quicker in R(–) carvone. In addition, the esterification yield changes depending on the stereochemistry of the carvone used as solvent. The formation of disteromeric complexes (chiral solvent + chiral substrates) may explain this finding.

Research paper thumbnail of Thermal stabilization of immobilized lipase B from Candida antarctica on different supports: Effect of water activity on enzymatic activity in organic media

Enzyme and Microbial Technology, 1999

Covalent immobilization of C. antarctica lipase B (CALB) on sepharose, alumina, and silica was un... more Covalent immobilization of C. antarctica lipase B (CALB) on sepharose, alumina, and silica was undertaken. The thermal stability of these covalently immobilized catalysts were studied and compared to adsorbed derivatives from Novo Nordisk at 50°C under wet conditions. Native enzyme and Novozym 435 follow a deactivation model E 3 E 1 whereas covalently immobilized derivatives and SP435A follow the model E 3 E 1 3 E 2. This different behavior is related to the nature of the support and the immobilization methodology. Water absorption isotherms of dry solid biocatalysts in air or isooctane were used to predict the optimum preequilibrium a w value to obtain the highest rate in the esterification of (r,s)-ibuprofen.

Research paper thumbnail of Covalent immobilization of pure isoenzymes from lipase of Candida rugosa

Enzyme and Microbial Technology, 1997

Covalent irnmobilizution of pure lipases A and B from Candida rugosa on agarose and silica is des... more Covalent irnmobilizution of pure lipases A and B from Candida rugosa on agarose and silica is described. The immobilization increases the half-life of the biocatalysts (tx. = 5 h) with respect to the native pure lipases (tl,? = 0.28 h). The percentage immobilization of lipases A and B is similar in both supports (33-40%). The remaining activity of the biocatalysts immobilized on agarose (70-75%) is greater than that of the enzymatic derivatives immobilized on SiO, (40-50%). The surjixce area and the hydrophobic/hydrophilic properties of the support control the lipase activiw of these derivatives. The thermal stability of the immobilized lipase A derivatives is greater than that of lipase B derivatives. The nature of the support influences the thermal deactivation profile of the immobilized derivatives. The immobilization in agarose (hydrophilic support) gives biocatalysts that show a greater initial specific reaction rate than the biocatalysts immobilized in Si02 (hydrophobic support) using the hydrolysis of the esters of(R) or(S) 2-chloropropanoic and of (R,S) 2-phenylpropanoic acids as the reaction test. The enzymatic derivatives are active for at least 196 h under hydrolysis conditions. The stereospecifi+v of the native and the immobilized enzymes is the same.

Research paper thumbnail of A new method to determine the aw range in which immobilized lipases display optimum activity in organic media

Biotechnology Techniques, 1996

... 199, 609-614. Arroyo, M.; Moreno, JM and Sitisterra, JV (1995) J. Mol. Catal. A: Chem. 97, 19... more ... 199, 609-614. Arroyo, M.; Moreno, JM and Sitisterra, JV (1995) J. Mol. Catal. A: Chem. 97, 195-201. De la Casa, RM; Stichez-Montero, JM and Sinisterra, JV (1996) Biotech. Lett. 18, 13-18. Norin, M.; Boutelje, J.; Holmberg, E. and Hult, K. (1988) Appl. Microbial. Biotechnol. ...

Research paper thumbnail of Influence of chiral carvones on selectivity of pure lipase-B from Candida antarctica

Biotechnology Letters, 1995

ABSTRACT In the esterification reaction in non-aqueous media lipase-B from Candida antarctica is ... more ABSTRACT In the esterification reaction in non-aqueous media lipase-B from Candida antarctica is stereoselective towards the R-isomer of ketoprofen in an achiral solvent such as isobutyl methyl ketone and in S(+) carvone. On the contrary, S(+) ketroprofen is esterified quicker in R(–) carvone. In addition, the esterification yield changes depending on the stereochemistry of the carvone used as solvent. The formation of disteromeric complexes (chiral solvent + chiral substrates) may explain this finding.