Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329354
Title: The production of catechols in glucose fed-batch culture using whole cells of Pseudomonas putida
Author: Robinson, Gary Kevin
ISNI:       0000 0001 3527 857X
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 1988
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Abstract:
The production of catechols, especially substituted catechols, has attracted industrial interest for the synthesis of high value-added compounds. Chemosynthetic routes are often complex and alternative methods using whole-cell biocatalysis are being investigated. The aim of this project was to investigate the production of catechol and 3-methyl catechol using benzene or toluene respectively, as the substrates. Different mutants were used for the bioconversion of toluene and benzene to their respective catechols. Both mutants were derived from the same Pseudomonas putida strain, namely P. putida 2313 which already lacked the extradiol cleavage enzyme, catechol 2,3-oxygenase and was able to accumulate 3-methyl catechol when fed with toluene in the presence of glucose. However P. putida 2313 still possessed catechol 1,2-oxygenase allowing the organism to grow on benzene. After mutagenesis P. putida 6(12), an organism lacking the intradiol cleavage enzyme, catechol 1,2-oxygenase, was selected for further study. P. putida strains 2313 and 6(12) were used as the biocatalyst in glucose-limited fed-batch cultures to achieve overproduction of either 3-methyl catechol or catechol. Under the conditions used, 11.5 mM (1.27 g/l) 3-methyl catechol and 27.5 mM (3 g/l) catechol were produced. Subsequently, two different product removal systems were employed in the 3-methyl catechol biotransformation and one of these, using an activated charcoal recycle column, resulted in the product yield being doubled. In conclusion, it was shown that both catechol and 3-methyl catechol can be produced using a whole-cell biotransformation. 3-methyl catechol was shown to be more toxic than catechol and the primary, though probably not exclusive, site of toxicity was the initial aromatic dioxygenase. Although overproduction of catechols was shown it would appear that the commercial production of these intermediates using a wholly biocatalytic route is limited by their inherent instability and resulting toxicity.
Supervisor: Not available Sponsor: Science and Engineering Research Council ; Shell Research Ltd
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.329354  DOI: Not available
Keywords: QD Chemistry
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