Carolina Aguirre

Carolina Aguirre
Universidad Católica de la Santísima Concepción | UCSC · Departamento de Química Ambiental

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16
Publications
912
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378
Citations
Citations since 2017
0 Research Items
106 Citations
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20172018201920202021202220230510152025
20172018201920202021202220230510152025

Publications

Publications (16)
Article
Full-text available
Synthesis of cephalexin with immobilized penicillin acylase at high substrates concentration at an acyl donor to nucleophile molar ratio of 3 was comparatively evaluated in aqueous and ethylene glycol media using a statistical model. Variables under study were temperature, pH and enzyme to substrate ratio and their effects were evaluated on cephale...
Article
The 2M1 strain of Aspergillus sp., which showed high extracellular xylanolytic activities in a pre-screening, was studied. Oat-spelt, birch, eucalyptus and pine xylans were used as xylanolytic inductors. The following activities were found at 50 ° C in the presence of 1′ xylan: 120 units/ml (oat-spelt xylan), 132 units/ml (birch xylan), 107 units/m...
Article
The impact of mass transfer limitations on penicillin G acylase immobilized in glyoxyl-agarose particles of different sizes and enzyme loads was evaluated for the reactions of hydrolysis of penicillin G and synthesis of cephalexin under the hypothesis that the impact of internal diffusional restrictions on the catalytic potential of the enzyme will...
Article
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-am...
Article
The use of very high substrate concentrations favors the kinetically controlled synthesis of cephalexin with penicillin acylase (PA) not only by Michaelian considerations, but also because water activity is depressed, so reducing the rates of the competing reactions of product and acyl donor hydrolysis. Commercial PGA-450, glyoxyl agarose immobiliz...
Article
The presence of organic cosolvents was previously considered necessary to obtain high conversion yields in the synthesis of β-lactam antibiotics with immobilized penicillin acylase, and it is so when working at moderate substrate concentrations. Conversion yields close to stoichiometric and high productivities were recently reported for the synthes...
Article
Full-text available
Foods with contrasting glycemic index when incorporated into a meal, are able to differentially modify glycemia and insulinemia. However, little is known about whether this is dependent on the size of the meal. The purposes of this study were: i) to determine if the differential impact on blood glucose and insulin responses induced by contrasting G...
Article
The effect of temperature was studied for the kinetically controlled synthesis of cephalexin and ampicillin with penicillin acylase immobilised in glyoxyl agarose. Yield increased at low temperatures in the absence and presence of ethylene glycol, while the initial ratio of synthesis to hydrolysis decreased. Arrhenius equations were used to describ...
Article
The synthesis of cephalexin with glyoxyl-agarose immobilised penicillin acylase (GAPA) in 50% (v/v) ethylene glycol at 90 mM acyl donor was optimised in terms of pH and temperature, using molar yield as objective function. Yield was substantially increased by the presence of the cosolvent and stability was also higher than in aqueous medium. pH and...
Article
The effect of co-solvents was studied on the kinetically controlled synthesis of cephalexin with immobilised penicillin acylase (PA). Yield correlated well with the ratio of initial rates of cephalexin synthesis to acyl donor hydrolysis and water activity. Yield was substantially higher in EG than in aqueous medium and was selected to study the eff...
Article
Immobilized penicillin acylase is a moderately priced versatile enzyme, that is able to catalyze the synthesis of derived penicillins and cephalosporins from the corresponding beta-lactam nuclei and proper side-chain precursors. Kinetically controlled synthesis is a better strategy when product yield is a key issue. Yield should increase at reduced...
Article
After screening 14 strains exhibiting high xylanase activities,Penicillium canescens (CP1) andPenicillium janthinellum Biourge (CP2) strains were selected. The β-xylanases produced had an optimum temperature and pH of 50°C and 4.0, respectively. Using a bleaching sequence of D100EP, D80EP, and XD80EP, the effluent color obtained with XD80EP was low...
Article
A plate-agar technique for fungal screening was applied to evaluate the xylanolytic activities of 18Penicillium janthinellum and 10Aspergillus sydowi species from the Amazon region. In order to compare these genera with those of other regions, oneAspergillus sp., one P.janthinellum, and 12 unknown genera from the southern region of Chile were studi...

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Project (1)
Project
Understanding the effects of heat and drought on Aristolochia chilensis and its predator Battus polydamas archidamas