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Enzyme Reaction Engineering: Effect of Methanol on the Synthesis of Antibiotics Catalyzed by Immobilized Penicillin G Acylase under Isothermal and Non‐Isothermal Conditions
Author(s) -
Travascio P.,
Zito E.,
Portaccio M.,
Diano N.,
Grano V.,
Martino S. Di,
Bertolini T.,
Rossi S.,
Mita D. G.
Publication year - 2002
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp010170v
Subject(s) - methanol , chemistry , penicillin amidase , catalysis , immobilized enzyme , membrane , isothermal process , membrane reactor , bioreactor , substrate (aquarium) , monomer , chromatography , nuclear chemistry , combinatorial chemistry , organic chemistry , enzyme , biochemistry , polymer , physics , oceanography , thermodynamics , geology
The effect of methanol on the kinetically controlled synthesis of cephalexin by free and immobilized penicillin G acylase (PGA) was investigated. Catalytic and hydrophobic membranes were obtained by chemical grafting, activation, and PGA immobilization on hydrophobic nylon supports. Butyl methacrylate (BMA) was used as graft monomer. Increasing concentrations of methanol were found to cause a greater deleterious effect on the activity of free than on that of the immobilized enzyme. Methanol, however, improved the kinetic stability of cephalexin synthesized by free PGA, resulting in higher maximum yields. By contrast, immobilized PGA reached 100% yields even in the absence of the cosolvent. Cephalexin synthesis by the catalytic membrane was also performed in a non‐isothermal bioreactor. Under these conditions, a 94% increase of the synthetic activity and complete conversion of the limiting substrate to cephalexin were obtained. The addition of methanol reduced the non‐isothermal activity increase. The physical cause responsible for the non‐isothermal behavior of the hydrophobic catalytic membrane was identified in the process of thermodialysis.