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Showing papers on "Penicillin amidase published in 1982"


Journal ArticleDOI
TL;DR: The synthesis of benzylpenicillin (BP) after mixing phenyl-acetyl-glycine (PAG), 6-aminopenicillanic acid (6-APA) and free or immobilized penicillin amidase (E.C.5.1.3.11) was studied as a function of pH and ionic strength.

34 citations


Journal ArticleDOI
TL;DR: It was demonstrated that the increased number of reactors in series could enhance the level of the maximum productivity with a given amount of enzyme loading and it was predicted in the tree‐stage PFR system that the optimal distributions of enzymes loading in three columns were found to be 1:1:1.
Abstract: A theoretical model equation was derived to find the correlation between the conversion and the amount of immobilized penicillin amidase in column. The theoretical values of the conversion were predicted form this correlation and compared with experimental results. It was observed in a column reactor that the pH drop along the column path was linear versus the enzyme loading and that the enzyme activity was also linearly dependent on pH up to 8.0. In order to diminish the effect of pH drop, a continuous two-stage plug-flow reactor (PFR) with pH adjustment between the two columns was used was used in the experiments, and two- and three-stage PFRs were simulated by computer. In the case of the two-stage PFR, the maximum productivity was demonstrated experimentally and theoretically as well. when an equal amount of the immobilized enzyme was packed in both columns. It was also predicted in the tree-stage PFR system that the optimal distributions of enzyme loading in three columns were found to be 1:1:1. It was demonstrated that the increased number of reactors in series could enhance the level of the maximum productivity with a given amount of enzyme loading.

25 citations


Journal ArticleDOI
TL;DR: Based on experimental results, two different kinetic models and reaction mechanisms of penicillin amidase show an ordered uni-bi reaction mechanism while the enzyme from Bacillus megaterium shows kinetics of double inhibition by the reaction products.

23 citations


Journal ArticleDOI
TL;DR: The regulation of the penicillin acylase in proteus rettgeri ATCC 31052 was compared with that of the enzyme in Escherichia coli ATCC 9637 and the P. reTTgeri enzyme was not induced by phenylacetic acid, nor was it subject to catabolite repression by glucose.
Abstract: The regulation of the penicillin acylase in proteus rettgeri ATCC 31052 was compared with that of the enzyme in Escherichia coli ATCC 9637. Unlike the E. coli acylase, the P. rettgeri enzyme was not induced by phenylacetic acid, nor was it subject to catabolite repression by glucose. The P. rettgeri acylase appears to be expressed constitutively but is subject to repression by the C4-dicarboxylic acids of the tricarboxylic acid cycle, succinate, fumarate, and malate.

22 citations


Journal ArticleDOI
TL;DR: Under these conditions the lactam ring of the benzylpenicillin and 6-aminopenicillanic acid and the enzyme, penicillin acylase, were more stable than in the absence of the polyol.

22 citations


Journal ArticleDOI
TL;DR: The effect of external mass transfer resistance on the overall reaction rate of the immobilized whole cell penicillin amidase of E. coli in a recirculation batch reactor was investigated and the correlation proposed by Chilton and Colburn represented adequately the experimental data.
Abstract: The effect of external mass transfer resistance on the overall reaction rate of the immobilized whole cell penicillin amidase of E. coli in a recirculation batch reactor was investigated. The internal diffusional resistance was found negligible as indicated by the value of effectiveness factor, 0.95. The local environmental change in a column due to the pH drop was successfully overcome by employing buffer solution. The reaction rate was measured by pH-stat method and was found to follow the simple Michaelis-Menten law at the initial stage of the reaction. The values of the net reaction rate experimentally determined were used to calculate the substrate concentration at the external surface of the catalyst pellet and then to calculate the mass transfer coefficient, k(L), at various flow rates and substrate concentrations. The correlation proposed by Chilton and Colburn represented adequately the experimental data. The linear change of log j(D) at low log N(Re) with negative slope was ascribed to the fact that the external mass transfer approached the state of pure diffusion in the limit of zero superficial velocity.

15 citations


Journal ArticleDOI
TL;DR: A partially constitutive mutant strain for penicillin Amidase production was derived from the parent strain Bacillus megaterium ATCC 14945 by treatment with UV light and showed two phenotypical changes in the mode of penicillim amidase production and in the size of cell chains.
Abstract: A partially constitutive mutant strain for penicillin amidase production was derived from the parent strain Bacillus megaterium ATCC 14945 by treatment with UV light. The mutant (B. megaterium KFCC 10029) showed two phenotypical changes in the mode of penicillim amidase production and in the size of cell chains. While the parent strain produced penicillin amidase only in the presence of an inducer, phenylacetic acid, the mutant strain could produce the enzyme without the inducer and the enzyme titer increased three to four times as much as that in the presence of the inducer. The mutant appeared as isolated single cells or short chains on the nutrient agar medium, whereas the parent strain usually appeared as long chains of cells.The composition of media was optimized including the inducer concentration. After finding the optimal sets of operating conditions with regard to the pH adjustment and the inducer addition time in a submerged culture, we were able to increase the enzyme productivity 7-8 times that without pH control. Although the correlation between two phenotypical changes is not yet clear, the mutant strain can be used as a potent producer of penicillin amidase.

7 citations