Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491714
Title: Biodegredation of aromatic compounds by extremely halophilic microorganisms
Author: Lee, Andrew Joseph
Awarding Body: Queen's University of Belfast
Current Institution: Queen's University Belfast
Date of Award: 2008
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Abstract:
Enrichment cultures, inoculated with a variety of samples from geographically and geologically distinct hypersaline environments, yielded a range of novel extremely halophilic microorganisms which could aerobically utilise several highly soluble aromatic compounds (benzoic acid, 4-hydroxybenzoic acid, 4-hydroxphenylacetic acid, phenylacetic acid and vanillic acid) as sole sources of carbon and energy for growth. 16S rRNA sequence data placed these isolates in the domain Archaea, with strains SALA1, SALD1 and SALD2 assigned to the genus Haloferax, strain SALF1 to the genus Halosarcilla, strains DSWB1 and SALF4 to the genus Halogeometriclllll, strains GSLC1 and MARl1 to the genus Haloarcllla and a final isolate, MARK1 assigned to the genus Haloterrigella. This is the first report of haloarchaea other than Haloferax and Haloarcula species degrading aromatic hydrocarbons. Growth on several of these aromatic compounds is unprecedented within the domain Archaea. Subsequent cell-free extract oxygen-uptake assays and inhibition studies using the phenylacetic acid and 4-hydroxyphenylacetic acid degrading strain Haloferax sp. SALD2 proved inconclusive, suggesting the possible existence of further, novel aerobic aromatic biodegradtion routes within the haloarchaea. However Halosarcina sp. SALF1, which could degrade 4-hydroxybenzoic acid, was found to possess gentisate 1,2-dioxygenase (gdo) genes which were homologous to the gdo sequences from the related strains, Haloferax sp. D1227, Haloarcllla sp. D1 and which were found to belong to a putative gdo gene family. Advantage was taken of recent developments in haloarchaeal cloning vectors and selectable markers to construct a non-replicative plasmid system that could be used for both random and targeted gene knockouts with members of the genus Haloferax. Clone libraries were successfully developed for Haloferax sp. D1227 with a view to investigating 3-hydroxybenzoic acid metabolism in this strain. However no transformants were obtained
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.491714  DOI: Not available
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