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Identifier |
000429148 |
Title |
Βελτιστοποίηση της παραγωγής β-φελλανδρενίου από ένα γενετικά τροποποιημένο κυανοβακτήριο |
Alternative Title |
Optimization of the production of β-phellandrene by a cyanobacterium genetically modified |
Author
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Ψυχογυιού, Μαρία Ελένη N.
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Thesis advisor
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Γανωτάκης, Δημήτριος
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Reviewer
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Παυλίδης, Ιωάννης
Τσιώτης, Γεώργιος
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Abstract |
In the present study the improvement of the terpenoid β-phellandrene production by the
cyanobacterium Synechocystis sp PCC 6803 was studied. The heterologous expression of
β-phellandrene synthase by this microorganism was achieved in previous studies after modifying
the cpc operon. This operon expresses phycocyanin, a pigment localized on the photosynthetic
antena of the microorganism, facilitating the capturing of the light energy in the low sea level were
the organism is existing and lower yield of sun radiation is approaching.
Different constructs of Synechocystis have been designed containg the gene of β-phellandrene
synthase in their genome. In this study, the increase of the yield of β-phellandrene was achieved by
studying a new construct Δcpc+cpcB.PHLS+cpcA.GPPS+cpc. The difference between this
construct and the previous studied is that all genes of cpc operon located in Wild Type have been
maintained, fusing the gene of the β-phellandrene synthase and the synthase of its procursor in the
biosynthatic pathway of endogenous terpenoids, geranyl diphosphate, with the genes expressing the
two subunits of phycocyanin. The presence of all genes was necessary for the overexpression of the
two synthases and led to higher production of the terpenoid. Furthermore, the organism follows
similar photosynthetic activity and growth to the wild type.
In the second chapter, the word “improvement” refers to the development of a more cost
effective and environmental friendly method for β-phellandrene production. Previous studies have
been conducted on the construct Δcpc+cpcB.PHLS+cpcA.GPPS under high salt concentration
including growth, photosynthetic activity and production, simulating the conditions in sea water,
which is available in huge amounts in the planet compared to fresh water. In addition, same
parameters were examined in alkaline environment which prevents the growth of a plethora of
microorganisms and can be used as a possible method to prevent contaminations. The new construct
was studied in same conditions, yet giving lower production of β-phellandrene. Moreover, both
Δcpc+cpcB.PHLS+cpcA.GPPS and Δcpc+cpcB.PHLS+cpcA.GPPS +cpc constructs were examined
in sea water. After cultivation in 100% sea water β-phellandrene production by both constructs was
achieved.
In the last chapter, Δcpc+cpcB.PHLS+cpc(-cpcA) construct was immobilised in alginic
polymeric spheres in 100% sea water and the system was studied for the ability to produce
β-phellandrene in 12 experimental days, using free cells in 100% sea water as control. Previous
studies in the laboratory showed that cell immobilisation concluded in the production of higher
amounts of β-phellandrene compared to BG-11 free cells cultures. The immobilised cells in sea
water produced similar yield observed in immobilised cells in BG-11, in contrast to free cells that
seem to be affected in growth and the yield of β-phellandrene production by the presence of sea
water.
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Language |
Greek |
Subject |
Biofuels |
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Cpc opero |
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Cpc οπερόνιο |
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Cyanobacteria |
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Fused genes |
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Geranyl diphosphate synthase (GPPS) |
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Monoterpenes |
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Photosynthesis |
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Phycocyanin |
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Synechocystis |
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Βιοκαύσιμα |
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Κυανοβακτήρια |
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Μονοτερπένια |
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Συνθάση του πυροφωσφορικού γερανυλίου (GPPS) |
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Συνθάση του φελλανδρενίου (PHLS) |
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Συντηγμένα γονίδια |
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Φυκοκυανίνη |
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β-phellandrene synthase (PHLS) |
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β-φελλανδρένιο |
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φωτοσύνθεση |
Issue date |
2020-03-27 |
Collection
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School/Department--School of Sciences and Engineering--Department of Chemistry--Post-graduate theses
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Type of Work--Post-graduate theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/3/1/4/metadata-dlib-1585213725-904135-27985.tkl
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Views |
654 |