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Title: Microbial degradation of benzene derivatives
Author: Chen, Beining
Awarding Body: University of Glasgow
Current Institution: University of Glasgow
Date of Award: 1991
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The thesis is divided into two parts. Both deal with the microbial metabolism of benzene derivatives but in different aspects. Part I attempts to elucidate some new mechanisms and stereochemistry involved in muconic acid pathways, which commonly occur in the microbial degradation of benzene derivatives. To investigate the conversion of 4-methyl into 3-methyl-muconolactone, three specially labelled muconolactones were tested with cell-free extracts of Rhodococcus rhodocrous. The results showed that the conversion of 4-methyl to 3-methylmuconolactone proceeds through two steps. Firstly, enzyme catalyses the formation of the new lactone ring by anti addition. Secondly the original lactone ring is opened enzymically by anti elimination. Dilactone was shown to be an intermediate. Studies on the inhibitors of the methylisomerase have been carried out from chemical point of view. Among the substituents studied, the larger substituents did not affect the biotransformation of pyrocatechols into corresponding muconolactones in Pseudomonas putida but affected those in Aspergillus niger. It was shown that the optical active 4-ethylmuconolactone can cyclise under mild condition giving the dilactone with opposite optical rotation, but 3,4-dimethylmuconolactone can not be cyclised under various conditions. In part II, it was hoped to delineate some influences of fluorine substituents on the biosynthesis of cyclopenin group of benzodiazepine alkaloids. Three fluoro-phenylalanines were tested with the fungus Penicillium cyclopium. The qualitative results obtained showed that these substrates have been incorporated into benzodiazepine alkaloids with low yields.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available