SciELO - Scientific Electronic Library Online

vol.17 número4-7Studies on the rheology and oxygen mass transfer in the clavulanic acid production by Streptomyces clavuligerusThermal stability and energy of deactivation of free and immobilized cellobiase índice de autoresíndice de assuntospesquisa de artigos
Home Pagelista alfabética de periódicos  

Serviços Personalizados




Links relacionados


Brazilian Journal of Chemical Engineering

versão impressa ISSN 0104-6632versão On-line ISSN 1678-4383


FERREIRA, A.L.O.; GONCALVES, L.R.B.; GIORDANO, R.C.  e  GIORDANO, R.L.C.. A simplified kinetic model for the side reactions occurring during the enzymatic synthesis of ampicillin. Braz. J. Chem. Eng. [online]. 2000, vol.17, n.4-7, pp.835-840. ISSN 0104-6632.

This work presents a kinetic study of the side reactions of the ampicillin enzymatic synthesis, from phenylglycine methyl ester and 6-aminopenicillanic acid using penicillin G acylase immobilized on agarose. A Michaelis-Menten model with competitive inhibition was fitted to initial rates of ester and antibiotic hydrolysis, at pH 6.5 and 25ºC. Inherent kinetic parameters were estimated for low enzymatic loads, to assure that diffusional resistance was not important. It was observed that ampicillin inhibits the hydrolysis of PGME, but the inhibitory effect of the ester on ampicillin hydrolysis was almost negligible. The obtained parameters were: kcat1= 0.025 mM/UI min, Km1 = 155.4mM, KAE = 16.18mM, kcat2= 4.67x10-3 mM/UI min, Km2 = 11.47, KEA = 0.68 mM. Parameter values are in the range reported in the literature, except for Km1, which is much higher. The large confidence interval for this parameter denotes that the model presents low sensitivity with respect to it.

Palavras-chave : Ampicillin hydrolysis; Penicillin G acylase; Immobilized enzyme; Kinetic model.

        · texto em Inglês


Creative Commons License Todo o conteúdo deste periódico, exceto onde está identificado, está licenciado sob uma Licença Creative Commons