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The role of amino acids in the amplification and quality of DNA vectors for industrial applications

Dorward, A; O'Kennedy, RD; Folarin, O; Ward, JM; Keshavarz-Moore, E; (2019) The role of amino acids in the amplification and quality of DNA vectors for industrial applications. Biotechnology Progress , 35 (6) , Article e2883. 10.1002/btpr.2883. Green open access

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Abstract

In this study, we have demonstrated that the type and feeding regimen of amino acids have a significant impact on the quality as well as the quantity of DNA vectors produced. Nutrient pool and factorial design experiments were carried out in order to identify the amino acids involved in increased biomass and induction of plasmid amplification. Leucine, glycine, and histidine were responsible for increased biomass and leucine starvation in the presence of histidine was implicated in plasmid amplification. Supercoiling of the plasmid was optimised using a dual feeding strategy. As a result of this, a fed-batch fermentation strategy for the production of a 6.9kb plasmid, pSVß, in Escherichia coli DH5α was developed. In batch fermentation, a maximum plasmid yield of 39.4mg/L equivalent to 11.3mg/g DCW was achieved with casein hydrolysate limitation. 90% of plasmid was in the supercoiled form after 31h of fermentation but only remained so for a short period, leading to a very brief window for harvesting cells at scale. Subsequently, a fed-batch fermentation using a dual feeding strategy was employed. A mean maximum plasmid yield of 44 mg/L equivalent to 9.1 mg plasmid/g DCW was achieved. After 25h, 90% of plasmid was in the supercoiled form and remained at this level for the remaining 10h of the fermentation, allowing adequate time for the harvesting of cells without the loss of supercoiling of product. This study emphasized that optimizing fermentation strategy and identifying the essential nutrients are beneficial for bioprocessing of plasmid DNA for therapeutic applications. This article is protected by copyright. All rights reserved.

Type: Article
Title: The role of amino acids in the amplification and quality of DNA vectors for industrial applications
Location: United States
Open access status: An open access version is available from UCL Discovery
DOI: 10.1002/btpr.2883
Publisher version: https://doi.org/10.1002/btpr.2883
Language: English
Additional information: This version is the author accepted manuscript. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Escherichia coli, amino acid starvation, fed-batch, plasmid amplification, semi-defined medium, supercoiling
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Biochemical Engineering
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering
URI: https://discovery.ucl.ac.uk/id/eprint/162662
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