uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Flocculate removal after alkaline lysis in plasmid DNA production.
2010 (English)In: Vaccine, ISSN 0264-410X, E-ISSN 1873-2518, Vol. 29, no 1, 6-10 p.Article in journal (Refereed) Published
Abstract [en]

Alkaline lysis is the most commonly used method following harvest of bacterial cells for production of plasmid DNA. The method was originally developed for laboratory scale experiments and has shown to be challenging at larger scales. A major problem prior to further downstream processing is the risk of filter clogging without efficient removal of the flocculate that occurs after neutralization. For this purpose we here present a scalable method where the clarification of alkaline lysate is greatly simplified. Through a rapid procedure, involving the addition of ammonium hydrogen carbonate to the neutralized alkaline lysate, the flocculate is lifted to the surface of the solution by the released carbon dioxide and ammonium. After this step a clarified solution can be drained from the bottom of the vessel. The procedure does not impact pH, plasmid DNA concentration or the ratio of open circular to supercoiled plasmid DNA in the solution.

Place, publisher, year, edition, pages
2010. Vol. 29, no 1, 6-10 p.
Keyword [en]
Alkaline lysis, Plasmid DNA, Flocculate removal
National Category
Chemical Sciences
URN: urn:nbn:se:uu:diva-172791DOI: 10.1016/j.vaccine.2010.10.021PubMedID: 20974301OAI: oai:DiVA.org:uu-172791DiVA: diva2:515770
Available from: 2012-04-16 Created: 2012-04-16 Last updated: 2012-08-01
In thesis
1. Purification Processes for Complex Biomacromolecules
Open this publication in new window or tab >>Purification Processes for Complex Biomacromolecules
2012 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis details various techniques and considerations for the purification of complex biomacromolecules.


Initially an α-mannosidase from babaco fruit was purified using anion exchange-, lectin affinity- and size exclusion chromatography.  The enzyme was approximately 260-280 kDa in size with an apparent an unusual octagonal stoichiometry and displayed properties similar to other known plant α-mannosidases.


Mucins were fractionated by ion exchange and size exclusion chromatography to assess the properties that govern the mucin surface coating interactions in biomaterial research.  Commercially available mucins, of bovine and porcine origin, as wells as crude human mucin were tested. All showed to consist of a population of molecules which differ in size, charge and composition.


The third part of the thesis concerns different aspects of plasmid DNA purification processes.

A two-step method for analysis of plasmid DNA consisting of size exclusion followed by thiophilic adsorption chromatography was evaluated. It allowed determination of the supercoiled plasmid DNA concentration in all process steps without requirement for extensive sample preparation. This method was shown to be fully comparable in terms of accuracy to capillary gel electrophoresis, considered as the industry standard.

Purification of plasmid DNA generally involves bacterial cell alkaline lysis, which creates a solution with flocculate material which needs to be removed prior to further processing. The addition of ammonium hydrogen carbonate to the suspension was evaluated to clarify the solution. The released carbon dioxide and ammonium lifts the flocculate to the surface and allows draining of a clear solution. The method is fully scalable, does not affect the plasmid DNA quality and requires no special equipment.

Thiophilic adsorption chromatography was evaluated for simplification of an existing commercial large scale purification process and was shown to increase both product purity and yields of several tested plasmids. Also, implementation of this step significantly reduced overall production process time.




Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2012. 61 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 928
Chromatography, enzymes, mucins, fractionation, plasmid DNA, analysis, clarification, process design
National Category
Chemical Sciences
Research subject
Chemistry with specialization in Surface Biotechnology
urn:nbn:se:uu:diva-172892 (URN)978-91-554-8353-1 (ISBN)
Public defence
2012-05-25, BMC B7:101, Husargatan 3, Uppsala, 13:15 (English)
Available from: 2012-05-04 Created: 2012-04-17 Last updated: 2012-08-01Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textPubMed

Search in DiVA

By author/editor
Blom, Hans
In the same journal
Chemical Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 267 hits
ReferencesLink to record
Permanent link

Direct link