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Kinetics and reaction engineering of penicillin G hydrolysis
Author(s) -
Kumar Ramachandran,
Suresh A. Krishnamurthy,
Shankar H. Subbaraman
Publication year - 1996
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/(sici)1097-4660(199607)66:3<243::aid-jctb488>3.0.co;2-o
Subject(s) - penicillin amidase , chemistry , pellets , diffusion , thiele modulus , substrate (aquarium) , product inhibition , phenylacetic acid , kinetics , penicillin , hydrolysis , enzyme kinetics , thermodynamics , immobilized enzyme , chromatography , chemical engineering , enzyme , organic chemistry , non competitive inhibition , biochemistry , materials science , mass transfer , physics , oceanography , quantum mechanics , engineering , composite material , geology , antibiotics , active site
A general diffusion reaction model for immobilised biocatalysis has been developed. The model has been used to study the deacylation of penicillin G to 6‐aminopenicillanic acid using two commercially available immobilised Penicillin acylases. The values of D e / R 2 for the enzyme pellets have been estimated using data on uptake of 6‐aminopenicillanic acid and phenylacetic acid by the enzyme pellets. The kinetic parameters of the model were individually estimated from a suitably designed set of experiments. The values of the Thiele modulus from the kinetic parameters so calculated have been found to be in the range 1·67 to 9·8 for the two enzymes studied, implying that diffusional effects cannot be ignored. The effect of such diffusional limitations on the overall rates and hence on the utilisation of the intrinsic kinetic ability of the enzyme has been demonstrated. This paper also reports on the implementation of the fed‐batch strategy for this system. The proposed strategy, which involves maintaining the substrate concentration at the optimum value for a large part of the conversion, results in higher product concentrations than in batch operation, thereby reducing downstream procesing costs. The productivity was also shown to be considerably higher than for batch operation. Further, the ease of implementation of this mode of operation has been demonstrated.