Robinson, Gary Kevin (1988) The production of catechols in glucose fed-batch culture using whole cells of Pseudomonas putida. PhD thesis, University of Warwick.

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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.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QD Chemistry
Library of Congress Subject Headings (LCSH):	Catechol -- Synthesis, Aromatic compounds -- Biodegradation, Pseudomonas, Biocatalysis, Bioreactors, Biotransformation (Metabolism), Mutagenesis
Official Date:	November 1988
Dates:	Date Event November 1988 Submitted
Institution:	University of Warwick
Theses Department:	Department of Biological Sciences
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Dalton, Howard
Sponsors:	Science and Engineering Research Council (Great Britain) ; Shell Research Ltd.
Format of File:	pdf
Extent:	xx, 270 leaves : illustrations, charts
Language:	eng

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