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Title: Isolation of novel microorganisms and antimicrobial activities from an Irish Triassic halite mine
Author: Alsharedeh, Rawan Hamdan
ISNI:       0000 0004 6423 2273
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2017
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Extremophilic microorganisms, including both halotolerant and halophilic bacteria and archaea, are a potentially untapped source for antimicrobial discovery. Hypersaline environments are receiving increasing interest in the search for novel antimicrobials. One such environment under investigation for its microbial biodiversity and potential antimicrobial diversity is Kilroot salt mine, Ireland’s only salt mine. The overall aim of this research was to explore its microbial biodiversity, through microbial isolation and identification, and to investigate these microbes as producers of antimicrobials with activity against the ESKAPE pathogens. In total 40 culturable isolates were obtained, two-thirds of which were halophilic, and one-third were halotolerant. Six halophilic isolates were proposed as a potential novel species, three of them were chosen for further investigation and extensive characterisation and are here reported as novel species of the Genus Salinisphaera. Following whole genome sequencing, genome mining results obtained from interrogation of the genomes using the antiSmash, and the RAST pipeline revealed the presence of various genes encoded in their genomes, including antibacterial peptide production, ectoine, siderophores, terpenes, and arylpolyenes production. Although culture based activity screening did not reveal antimicrobial activity, further investigations perhaps involving activation of silent gene clusters may yield novel and interesting antimicrobial activities. Isolate AB-7 from the genus Bacillus, exhibited antimicrobial activity against all ESKAPE strains. The Preliminary identification of the active compound indicated that it is non-proteinaceous, and could withstand heating up to 100°C. The structural elucidation of the purified compound identified it as indole. In the second isolate AC-12 from the genus Halovibrio, exhibited antimicrobial activity against all ESKAPE pathogens except P. aeruginosa. The preliminary identification of the active compound indicated that it is in part proteinaceous, and heat stable. This revealed that organisms from the hypersaline environments, are potential source for antimicrobials production.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available