Yang, Luyao;
(2025)
Chloroplast engineering in the green alga Chlamydomonas for production of novel recombinant products.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
The edible microalga Chlamydomonas reinhardtii has emerged as a promising platform for producing high-value compounds and has been applied broadly, such as recombinant therapeutics and biomaterials. Growth rates and disease control are two major limiting factors in aquaculture, but both could be addressed through oral delivery of affordable therapeutics. Fish growth hormones (fGHs) have been shown to promote the growth of fish and shellfish, and specific double-stranded RNA (dsRNA) molecules designed to key viral genes can serve as RNA-based vaccines. When taken up by animals, the dsRNA can trigger the RNA interference (RNAi) mechanism and produce small interfering RNA (siRNA) that silence viral genes. The study sets out to produce fGHs and dsRNAs in the chloroplast of C. reinhardtii to develop a system for whole-cell bio-encapsulation and oral delivery. Initial studies used shrimp as a model and focused on the optimisation of fGHs and dsRNA administration doses, shrimp growth and viral challenge performance, as well as optimisation of a low-cost ‘hanging bag’ photobioreactor system used for scale-up production of the algae to produce sufficient dried biomass for further shrimp feeding trials. Furthermore, a novel recipient strain psaA** was developed and tested to optimise the chloroplast transformation method for the simple generation of marker-free transformants. Spider silk protein is a biomaterial in wide applications as its outstanding mechanical features are biodegradable and biocompatible. However, spider silk production has many limitations, especially the challenging, time-consuming, and expensive collecting process. Recombinant production was attempted in various systems, with microalga C. reinhardtii as one of the promising organisms. Several types of recombinant spider silk proteins attract extra attention, particularly major ampullate spidroin (MaSp), such as MaSp1 and MaSp2. Transgenic lines of C. reinhardtii that appear to accumulate the different sizes of repetitive MaSp1 protein were created and cultivated under photoheterotrophic and photoautotrophic growth conditions.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Chloroplast engineering in the green alga Chlamydomonas for production of novel recombinant products |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2025. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/deed.en). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Life Sciences > Div of Biosciences |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10217736 |
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