Zhuang, Yibin;
(2025)
Towards the establishment of an efficient and scalable
recovery process for pneumococcal glycoconjugate
vaccines produced in Escherichia coli.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
Commercial pneumococcal glycoconjugate vaccines are effective but have high cost per dose, primarily due to the multi-step chemical conjugation-based manufacturing process. In contrast, the Protein Glycan Coupling Technology offers a more economical alternative to produce pneumococcal glycoconjugate vaccines based on Escherichia coli fermentation, where a critical aspect of this process is the efficient recovery of periplasmic glycoconjugate vaccine products. This thesis aims to develop an efficient and scalable recovery process for pneumococcal glycoconjugate vaccines produced in Escherichia coli, employing a periplasmic extraction method as an alternative to conventional cell disruption via homogenisation. A sodium deoxycholate-based (DOC) treatment method exhibited superior product extraction efficiency during the screening of various periplasmic extraction methods, which was subsequently optimised using the Design of Experiment methodology. The optimised DOC extraction conditions were: 150 mM Tris-HCl, pH 8.3, 1.5 % w/v DOC, incubated for one hour under room temperature, with agitation at 1800 rpm, and a sample OD600 of 40. This method consistently achieved a 110% glycoconjugate yield per unit of OD600 of that by homogenisation. Successful scale up of this method was conducted from 2-mL shaken Eppendorf tubes to 250-mL miniature stirred tank bioreactors. Furthermore, the DOC extraction method developed in this thesis also contributed to improved clarification by centrifugation compared to homogenisation, with no observed adverse impact on product capture in column chromatography. The work presented represents a first step toward the development of a robust and scalable product recovery process, with the goal of enabling industrial-scale manufacturing of PGCT-derived glycoconjugate vaccines.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Towards the establishment of an efficient and scalable recovery process for pneumococcal glycoconjugate vaccines produced in Escherichia coli |
| 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/). 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 > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Biochemical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10216952 |
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