Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.554899
Title: An investigation into the biodegradation of peptide cyanotoxins (microcystins and nodularin) by novel gram-positive bacteria
Author: Welgamage Don, Aakash Channa Dharshan
Awarding Body: Robert Gordon University
Current Institution: Robert Gordon University
Date of Award: 2012
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Abstract:
Cyanobacterial secondary metabolites, microcystins (MC) and nodularin (NOD) have become common contaminants in most aquatic ecosystems over recent years presenting a hazard to animal and human health. Unfortunately, these chemically diverse peptide hepatotoxins remain a challenge to most conventional water treatments due to their stable cyclic structures. Over recent years, bioremediation of MC and NOD has become one of the most exciting areas that holds promise for a successful and cost effective solution for water treatment process. The current work presents the biodegradation of MCs and NOD by bacterial isolates from three different bacteria genus Arthrobacter, Brevibacterium and Rhodococcus belonging to Actinobacteria. A total of five isolates representing the three genera have demonstrated an overall metabolism of MC-LR, -LF, -LY, -LW, -RR and NOD in a Biolog MT2 assay. Subsequently, these bacteria were reported to degrade the range of toxins in a separate batch experiment. The bacterial degradation rate of the above cyanobacterial peptides were found to decrease with the multiple subculturing of the bacteria. However, a rapid degradation was discovered when the bacteria were re-exposed to MC or other prokaryotic peptides demonstrating an inducible bacterial biodegradation. Utilising latest molecular biology techniques, the gene responsible for production of MC degrading enzymes was successfully elucidated and its activity was evaluated. Analysis of the degradation products of MC-LR revealed a glutathione conjugate detoxification mechanism involved during the degradation of MC-LR by Rhodococcus sp. (C1). A novel MC degradation pathway was proposed. Further studies were suggested to fully characterise the degradation pathway and to evaluate the MC detoxification mechanism in bacteria.
Supervisor: Lawton, Linda A. ; Edwards, Christine Sponsor: Robert Gordon University: Institute for Innovation, Design and Sustainability
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.554899  DOI: Not available
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