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Identifier 000434071
Title Μελέτη της ακραιόφιλης συμπεριφοράς του λειχήνα Pleurosticta acetabulum σε ακραία UVB-ακτινοβολία σε σχέση με την μεταβολική του δυνατότητα να παράγει υδρογόνο
Alternative Title Study of the extremophilic behavior of the lichen Pleurosticta acetabulum at extreme UVB-radiation in relation to its metabolic capacity to produce hydrogen
Author Κυριατζή, Αναστασία Ν.
Thesis advisor Κοτζαμπάσης, Κυριάκος
Reviewer Πυρίντσος, Στέργιος
Σαρρής, Παναγιώτης
Abstract The purpose of this work is to demonstrate the extremophilic behavior of the lichen Pleurosticta acetabulum at extreme UVB radiation (1.7 mW/cm2= 1000 J/m2 .min) for various time periods (4, 20 & 70h) maintaining its metabolic capacity to produce hydrogen (H2). Lichen is a special micro-ecosystem, which consisted of a fungus and a green alga or cyanobacterium. The fungus offers water to photosynthetic organism, which in exchange provides chemical energy through photosynthesis. The particularity of this symbiotic system is its ability to remove (all) moisture and to remain in an inactive state in order to be protected from extreme conditions. The results of this project prove the ability of lichen to survive under extreme UVB radiation for long time, both in dehydrated and in regenerated form. The lichen viability was tested using fluorescence induction techniques (OJIP-test), which records changes in molecular structure and function of the photosynthetic mechanism. Based on the results of gas chromatography, using thermal conductivity detector (GC-TCT), it is demonstrated that the lichen can retain its ability to produce large amount of molecular hydrogen when it exposed in high intensities of UVB radiation. Furthermore, combined expose of lichen to high intensity of UVB radiation, vacuum conditions (10 mbar for 24 hours) and extreme temperatures (-196oC and +70oC) highlighted its poly-extremophilic behavior. The lichen remain substantially unaffected and recovered completely when condition changed (regeneration in water) maintaining its ability to produce large amount of hydrogen only by adding water in a close system. Hydrogen is a promising fuel for the future and this ability of the lichen micro-ecosystem to withstand extreme conditions and to produce large amount of hydrogen, without the need of additional energy, allows the use of lichens for future biotechnological applications even in extreme environments of other planets, such as Mars, paving the way for astrobiological and astrobiotechnological applications.
Language Greek
Subject Astrobiology
Extremophiles
Hydrogen production
Lichens
Symbiosis
Ακραιοφιλή
Αστροβιολογία
Λειχήνες
Παραγωγή υδρογόνου
Συμβίωση
Issue date 2020-11-27
Collection   School/Department--School of Sciences and Engineering--Department of Biology--Post-graduate theses
  Type of Work--Post-graduate theses
Permanent Link https://elocus.lib.uoc.gr//dlib/d/6/f/metadata-dlib-1605779178-409906-7970.tkl Bookmark and Share
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