Saudi Arabia is highly accessible to marine water, receives year-round availability of
sunlight and generates a high annual carbon dioxide emission, all of which are
justifications that merits the deployment of cyanobacterial cell factories. However,
industrial cyanobacterial strains capable of thriving in conditions of the Arabian
Peninsula are currently lacking. Given the fact that native cyanobacteria from the
Red Sea are adapted to the local conditions, they are therefore good cell factory
candidates where their inherent attributes can be harnessed. In this dissertation, an
isolation and screening pipeline was developed to specifically identify
physiologically robust cyanobacterial strains from the central Red Sea. Seventeen
unicellular cyanobacterial strains were extensively cataloged through a series of
physiological characterization and their evolutionary relationships were
ascertained through phylogenetic analyses. Arising from this survey work, a high
light, thermo- and halo-tolerant Synechococcus sp. RSCCF101 was selected for
metabolic analysis under various growth conditions to assess its suitability as a
platform for cell factory development. Significant metabolic changes were observed
in cells subjected to different light regimes. High phycocyanin and chlorophyll a
content were obtained under the low-light growth (50 μmol photons.m-2.s-1) while
high biomass was accumulated, along with an increase external nitrate demand,
under the high light growth (200 μmol photons.m-2.s-1). A genomic and
transcriptomic approach was undertaken to elucidate the molecular signatures of
Synechococcus sp. RSCCF101. Synechococcus sp. RSCCF101 contains a small genome
(3 Mbp) that is rich in guanine cytosine content (68%) and harbors genes that
encode for compatible solutes biosynthetic pathway and phycobilisome subunits
which may account for its halo-tolerant and phycocyanin rich phenotype. Upon
high-light treatment, the light harvesting machineries of Synechococcus sp.
RSCCF101 was downregulated while the photosystem protection and carbon
fixation capacity were upregulated. Taken together, the findings of this research will
facilitate in the development of a new model system for industrial applications in
high-light, high temperature and high salinity environments in general and Saudi
Arabia in particular.
| Identifer | oai:union.ndltd.org:kaust.edu.sa/oai:repository.kaust.edu.sa:10754/631961 |
| Date | 04 1900 |
| Creators | Ng, Yi Mei |
| Contributors | Gojobori, Takashi, Biological and Environmental Sciences and Engineering (BESE) Division, Archer, John A.C., Arold, Stefan T., Moran, Xose Anxelu G., Lindblad, Peter |
| Source Sets | King Abdullah University of Science and Technology |
| Language | English |
| Detected Language | English |
| Type | Dissertation |
| Rights | 2019-04-21, At the time of archiving, the student author of this dissertation opted to temporarily restrict access to it. The full text of this dissertation became available to the public after the expiration of the embargo on 2019-04-21. |
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