Structural mechanics and collective self-organisation in filamentous cyanobacteria

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Faluweki, MK ORCID: https://orcid.org/0000-0002-9542-9971, 2023. Structural mechanics and collective self-organisation in filamentous cyanobacteria. PhD, Nottingham Trent University.

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Abstract

Filamentous cyanobacteria, one of the earliest types of organisms to have evolved on Earth, are photoautotrophs made of single cells joined together in long filaments. They are ubiquitous, living in water, soil, rocks and extreme environments like hot springs. Their oxygen production is believed to have led to the evolution of oxygen-dependent organisms like us. They live in colonies forming biomats, and are associated with stromatolites, which are important for understanding the evolution of early life. Commercially, filamentous cyanobacteria are used for biofuel production, food supplements, cosmetics and medicines. In order to maximise the usage of these microorganisms, we must understand how individual filaments interact and form collective structures. This thesis, therefore, focuses on quantifying the mechanical properties and collective organisation of filamentous cyanobacteria. First, the structural and mechanical properties of the filaments, such as the bending stiffness, are quantified. The mechanical properties are linked to their shapes, to predict the magnitude of internally generated active forces. These results can be used to model cyanobacteria motion and self-organisation. Next, this thesis looks at the behaviour of filaments in isolation and when interacting with other filaments or walls. These results provide parameters such as filament speed, angular drift and curvature that are then used by collaborators for modelling and predicting the collective behaviour of the cyanobacteria. The last part of this thesis provides experimental evidence of how self-organisation occurs for filamentous cyanobacteria in an open space and in confinement. A density-dependent phase transition was found, between disordered and nematically ordered patterns of filamentous cyanobacteria. Finally, in confinement studies, it was observed that certain chamber geometries, e.g. circular, promote unequal filament distribution. The results here are applicable in areas such as the study of stromatolites and the evolution of early life, and in the production of algae-based biofuels.

Item Type:	Thesis
Creators:	Faluweki, M.K.
Date:	May 2023
Rights:	The copyright in this work is held by the author. You may copy up to 5% of this work for private study, or personal, non-commercial research. Any re-use of the information contained within this document should be fully referenced, quoting the author, title, university, degree level and pagination. Queries or requests for any other use, or if a more substantial copy is required, should be directed to the author.
Divisions:	Schools > School of Science and Technology
Record created by:	Jeremy Silvester
Date Added:	02 Jun 2023 12:52
Last Modified:	02 Jun 2023 12:52
URI:	https://irep.ntu.ac.uk/id/eprint/49103