Dr.-Ing. Julia Sieberz

Julia Sieberz studied Biochemical Engineering at the Technical University of Dortmund since 2005. She finished her degree in September 2010 with a diploma thesis dealing with the process evaluation of the extraction of Rebaudisid A from Stevia rebaudiana.

From December 2008 to December 2013, she was working at the Laboratory of Plant and Process Design on her PhD. Her research was focused on the purification of monoclonal antibodies with polyelectrolytes.

Due to the great demand for monoclonal antibodies (mAbs) for diagnostic and therapeutic applications there is a growing need to increase the throughput of the production process. In addition, a reduction of costs of goods is desired, especially in downstream processing, which often makes up to 50 – 80 % of the total costs of bioprocesses. Existing purification processes of mAbs usually consist of a series of chromatographic methods, e.g. affinity and ion exchange chromatography, which often results in high process costs. Thus it is important to develop new cost-efficient and robust purification methods which can replace traditional process concepts.

A new promising purification method is the precipitation of mAbs with polyelectrolytes. Polyelectrolytes are poly-charged polymers which can form complexes with proteins of opposite charge. Variation of solution properties, e.g. pH-value and ionic strength, causes the formation of insoluble complexes. Depending on the polymer properties, either the target protein or the impurities can be precipitated out of the fermentation broth.

Dissertation

• J. Sieberz
  A Contribution to Protein Purification with Polyelectrolytes
  TU Dortmund, 2017, Verlag Dr. Hut, München ISBN 978-3-8439-3298-1

Paper

• J. Sieberz, E. Cinar, K. Wohlgemuth, G. Schembecker
  Clarification of a monoclonal antibody with cationic polyelectrolytes: analysis of influencing parameters
  Biochemical Engineering Journal 122 (2017) 60–70, doi.org/10.1016/j.bej.2017.02.011
   
• J. Sieberz, K. Wohlgemuth, G. Schembecker
  The influence of impurity proteins on the precipitation of a monoclonal antibody with an anionic polyelectrolyte
  Separation and Purification Technology 146 (2015) 252-260, doi.org/10.1016/j.seppur.2015.03.055
   
• J. Sieberz, B. Stanislawski, K. Wohlgemuth, and G. Schembecker
  Identification of parameter interactions influencing the precipitation of a monoclonal antibody with anionic polyelectrolytes
  Separation and Purification Technology 127 (2014) 165–173, doi.org/10.1016/j.seppur.2014.02.033

Oral presentations

• J. Sieberz, K. Wohlgemuth, B. Stanislawski, G. Schembecker
  Optimization of the precipitation of a monoclonal antibody with anionic polyelectrolytes
  Fourth Annual Retreat of the CLIB-Graduate Cluster, Lünen, Germany (2013)
   
• J. Sieberz, K. Wohlgemuth, B. Stanislawski, G. Schembecker
  Monoclonal antibody purification using polyelectrolytes
  GVC/ DECHEMA Vortrags- und Diskussionstagung “Biopharmazeutische Produktion”, Halle, Germany (2013)
   
• J. Sieberz, E. Dischlov, B. Stanislawski, G. Schembecker
  Precipitation of a monoclonal antibody with anionic polyelectrolytes
  GVC/ DECHEMA Vortrags- und Diskussionstagung “Biopharmazeutische Produktion”, Freiburg, Germany (2012)

Poster presentations

•  J. Sieberz, K. Wohlgemuth, B. Stanislawski, G. Schembecker
  Precipitation of a monoclonal antibody with anionic polyelectrolytes
  Fourth Annual Retreat of the CLIB-Graduate Cluster, Lünen, Germany (2013)
   
• J. Sieberz, K. Wohlgemuth, B. Stanislawski, G. Schembecker
  Precipitation of a monoclonal antibody with anionic polyelectrolytes
  GVC/ DECHEMA Vortrags- und Diskussionstagung “Biopharmazeutische Produktion”, Bad Wildungen, Germany (2013)
   
• J. Sieberz, E. Dischlov, B. Stanislawski, G. Schembecker
  Investigation of the purification of a monoclonal antibody with anionic polyelectrolytes
  Third Annual Retreat of the CLIB-Graduate Cluster, Bergisch Gladbach, Germany (2012)
   
• J. Sieberz, K. Wohlgemuth, B. Stanislawski, G. Schembecker
  Aufreinigung monoklonaler Antikörper mit Polyelektrolyten
  ProcessNet “Jahrestagung”, Karlsruhe, Germany (2012)
   
• J. Sieberz, K. Wohlgemuth, B. Stanislawski, G. Schembecker
  Investigation and optimization of the precipitation of a monoclonal antibody (mAb) with polyelectrolytes
  9th European Symposium on Biochemical Engineering Science, Istanbul, Turkey (2012)
   
• J. Sieberz, B. Burghoff, B. Stanislawski, G. Schembecker
  Industrial purification of monoclonal antibodies with polyelectrolytes
  Second Annual Retreat of the CLIB-Graduate Cluster, Bonn, Germany (2011)