Development of Synechococcus sp. PCC 11901 as a biotechnology platform

Mills, Lauren (2022) Development of Synechococcus sp. PCC 11901 as a biotechnology platform. Doctoral thesis, University of East Anglia.

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Abstract

Cyanobacteria are key organisms in the global ecosystem and potential renewable platforms for production of chemicals. Many aspects of cyanobacterial biology are unique to this subset of prokaryotes. Characterising cyanobacterial metabolism and physiology is key to understanding their environmental role and unlocking their potential for biotechnology. This thesis provides a comprehensive summary of our knowledge on cyanobacterial physiology and the pathways in the model organism, Synechocystis sp. PCC 6803 (PCC 6803). One of the main issues within cyanobacterial bioindustry has been the lack of sustained fast-growing strains. The newly discovered Synechococcus sp. PCC 11901 (PCC 11901) reportedly demonstrates the highest, most sustained growth of any known cyanobacterium. Knowledge of PCC 11901 biology, including the factors underlying the sustained fast growth, is limited, which hinders its potential for biotechnology. Genetic tools for generating unmarked mutants in PCC 11901 are not established. This thesis confirms that PCC 11901 displays faster growth than other model cyanobacteria. Comparative genomics between PCC 11901 and PCC 6803 reveal conservation of most metabolic pathways but PCC 11901 has a simplified electron transport chain and reduced light-harvesting complex. This may underlie its efficient light use, reduced photoinhibition, and higher photosynthetic and respiratory rates. Attempts to generate unmarked knockouts using two negative selectable markers were unsuccessful, suggesting that recombinase or CRISPR-based approaches may be necessary for the industry requirement of repeated genetic manipulation. To further cement PCC 11901 as a future industrial strain, biomass and optical density measurements were carried out over a range of light intensities to aid photo-mechanistic modelling of the strain. This thesis establishes PCC 11901 as one of the most promising species currently available for cyanobacterial biotechnology and provides a useful set of bioinformatic tools and strains for advancing this field, in addition to insights into the factors underlying its fast growth phenotype.

Item Type:	Thesis (Doctoral)
Faculty \ School:	Faculty of Science > School of Biological Sciences
Depositing User:	Chris White
Date Deposited:	23 Aug 2023 09:36
Last Modified:	23 Aug 2023 09:36
URI:	https://ueaeprints.uea.ac.uk/id/eprint/92914
DOI:

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