| dc.creator | Aguirre Céspedes, Carolina | |
| dc.creator | Concha, Irene | |
| dc.creator | Vergara, Judith | |
| dc.creator | Riveros, Ruby | |
| dc.creator | Illanes, Andrés | |
| dc.date | 2015-12-02T15:37:11Z | |
| dc.date | 2015-12-02T15:37:11Z | |
| dc.date | 2010 | |
| dc.identifier | Process Biochemistry 45 | |
| dc.identifier | 1359-5113 | |
| dc.identifier | http://repositoriodigital.ucsc.cl/handle/25022009/675 | |
| dc.description | Artículo de publicación ISI | |
| dc.description | The kinetically controlled synthesis of cephalexin in aqueous two-phase systems was studied, using immobilized penicillin acylase, 7-amino 3-desacetoxycephalosporanic acid as nucleophile and phenylglycine methyl ester as acyl donor. The organic phases used were 80% (v/v) polyethyleneglycol 400 and 600 and the aqueous phase was 2.5 M (NH4)2SO4. 7-amino 3-desacetoxycephalosporanic acid and cephalexin partition coefficients were determined at pH 7.4 and 7.8, at 14 °C and 20 °C. Highest partition coefficient for cephalexin was obtained for polyethyleneglycol 400–(NH4)2SO4 at pH 7.4 and 20 °C, while the lowest partition coefficient for 7-amino desacetoxycephalosporanic acid was obtained in the same system at pH 7.8 and 14 °C. No significant effect of pH was observed on conversion yield and productivity of cephalexin synthesis; however, higher values were obtained with polyethyleneglycol 400 as organic phase. Higher conversion yields with both biphasic systems were obtained at the lowest temperature, where product hydrolysis was lower; volumetric productivity was higher for the fully aqueous medium (control), being higher at 20 °C. All parameters of synthesis were improved at higher substrates concentrations, obtaining conversion yields of 78.2% and 65.4%, with 60 mM 7-amino desacetoxycephalosporanic acid for the polyethyleneglycol 400–(NH4)2SO4 system and the control, respectively. | |
| dc.language | en | |
| dc.publisher | Elsevier | |
| dc.rights | Atribucion-Nocomercial-SinDerivadas 3.0 Chile | |
| dc.rights | http://creativecommons.org/licenses/by-nc-nd/3.0/cl/ | |
| dc.source | http://goo.gl/07SWmR | |
| dc.subject | Penicillin acylase | |
| dc.subject | cephalexin | |
| dc.subject | β-Lactam antibiotics | |
| dc.subject | enzymatic synthesis | |
| dc.subject | partition coefficient | |
| dc.subject | aqueous two-phase systems | |
| dc.title | Partition and substrate concentration effect in the enzymatic synthesis of cephalexin in aqueous two-phase systems | |
| dc.type | Article | |
