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Dive into the research topics where Werner Bäcker is active.

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Featured researches published by Werner Bäcker.


Biotechnology Journal | 2013

Continuous purification of antibodies from cell culture supernatant with aqueous two-phase systems: From concept to process

Paula A. J. Rosa; Ana M. Azevedo; Sven Sommerfeld; Martina Mutter; Werner Bäcker; M. Raquel Aires‐Barros

An aqueous two-phase extraction (ATPE) process based on a PEG/phosphate system was developed for the capture of human immunoglobulin G and successfully applied to a Chinese hamster ovary and a PER.C6® cell supernatant. A continuous ATPE process incorporating three different steps (extraction, back-extraction, and washing) was set up and validated in a pump mixer-settler battery. Most of the higher molecular weight cell supernatant impurities were removed during the extraction step, while most of the lower molecular weight impurities were removed during the subsequent steps. A global recovery yield of 80% and a final protein purity of more than 99% were obtained for the IgG purification from a CHO cell supernatant, representing a 155-fold reduction in the protein/IgG ratio. For the purification of IgG from a PER.C6® cell supernatant, a global recovery yield of 100%, and a host cell protein purity were attained, representing a 22-fold reduction in the host cell protein/IgG ratio. These results, thus, open promising perspectives for the application of the developed ATPE process as a platform for the capture of antibodies. In fact, this new process has shown the ability to successfully recover and purify different antibodies from distinct cell culture supernatants. This technology can also overcome some of the limitations encountered using the typical chromatographic processes, besides inherent advantages of scalability, process integration, capability of continuous operation, and economic feasibility.


Journal of Chromatography B | 2012

Continuous aqueous two-phase extraction of human antibodies using a packed column

P.A.J. Rosa; Ana M. Azevedo; Sven Sommerfeld; Werner Bäcker; M.R. Aires-Barros

The performance of a pilot scale packed differential contactor was evaluated for the continuous counter-current aqueous two-phase extraction (ATPE) of human immunoglobulin G (IgG) from a Chinese hamster ovary (CHO) cells supernatant (CS) enriched with pure protein. Preliminary studies have been firstly performed in order to select the dispersed phase (phosphate-rich or polyethylene glycol 3350 Da (PEG)-rich phase) and the column packing material. The PEG-rich phase has been selected as the dispersed phase and the stainless steel as the preferred material for the column packing bed since it was not wetted preferentially by the selected dispersed phase. Hydrodynamic studies have been also performed, and the experimental results were successfully adjusted to the Richardson-Zaki and Mísek equations, typically used for the conventional organic-aqueous two-phase systems. An experimental set-up combining the packed column with a pump mixer-settler stage showed to have the best performance and to be advantageous when compared to the IgG batch extraction. An IgG recovery yield of 85% could be obtained with about 50% of total contaminants and more than 85% of contaminant proteins removal. Mass transfer studies have revealed that the mass transfer was controlled by the PEG-rich phase. A higher efficiency could be obtained when using an extra pump mixer-settler stage and higher flow rates.


Journal of Chromatography A | 2009

Downstream processing of antibodies: Single-stage versus multi-stage aqueous two-phase extraction

P.A.J. Rosa; Ana M. Azevedo; I.F. Ferreira; Sven Sommerfeld; Werner Bäcker; M.R. Aires-Barros

Single-stage and multi-stage strategies have been evaluated and compared for the purification of human antibodies using liquid-liquid extraction in aqueous two-phase systems (ATPSs) composed of polyethylene glycol 3350 (PEG 3350), dextran, and triethylene glycol diglutaric acid (TEG-COOH). The performance of single-stage extraction systems was firstly investigated by studying the effect of pH, TEG-COOH concentration and volume ratio on the partitioning of the different components of a Chinese hamster ovary (CHO) cells supernatant. It was observed that lower pH values and high TEG-COOH concentrations favoured the selective extraction of human immunoglobulin G (IgG) to the PEG-rich phase. Higher recovery yields, purities and percentage of contaminants removal were always achieved in the presence of the ligand, TEG-COOH. The extraction of IgG could be enhanced using higher volume ratios, however with a significant decrease in both purity and percentage of contaminants removal. The best single-stage extraction conditions were achieved for an ATPS containing 1.3% (w/w) TEG-COOH with a volume ratio of 2.2, which allowed the recovery of 96% of IgG in the PEG-rich phase with a final IgG concentration of 0.21mg/mL, a protein purity of 87% and a total purity of 43%. In order to enhance simultaneously both recovery yield and purity, a four stage cross-current operation was simulated and the corresponding liquid-liquid equilibrium (LLE) data determined. A predicted optimised scheme of a counter-current multi-stage aqueous two-phase extraction was hence described. IgG can be purified in the PEG-rich top phase with a final recovery yield of 95%, a final concentration of 1.04mg/mL and a protein purity of 93%, if a PEG/dextran ATPS containing 1.3% (w/w) TEG-COOH, 5 stages and volume ratio of 0.4 are used. Moreover, according to the LLE data of all CHO cells supernatant components, it was possible to observe that most of the cells supernatant contaminants can be removed during this extraction step leading to a final total purity of about 85%.


Separation Science and Technology | 2008

Process Design Method for Manufacturing of Natural Compounds and Related Molecules

Eugene Ndocko Ndocko; Werner Bäcker; Jochen Strube

Abstract Natural active compounds from plants have an increasing economic meaning in all areas of life sciences like e.g., food additives, cosmetics, pharmaceuticals and crop protection. The main task in manufacturing larger amounts of these plant based products besides raw material supply, product stabilization, and quality assurance, is an efficient process development method and economic production technology. State of the art approach is used in standard extraction methods. Initially their quantities are determined in isolation of laboratory scale testing and then transferred into large‐scale production by keeping all operation parameters constant in order to keep product quality constant. Nowadays the problem is that in most cases besides any missing process optimization with regard to necessary economical objectives, equipment is used with no modern process control, automation or process integration design applied. This study is a first proposal for a systematical process development and design methodology. It should address the need for efficient process evaluation of many compounds at an early stage and process optimization for manufacturing. Due to sustainability and economy the maximal yield contained of any target compounds in plants should be extracted, but this increases as well the side component amount and type extracted and thereby decreases product purity. Therefore, any approach to optimization, should be integrated with a process development and evaluation of additional purification steps. This article describes the experimental setup as well as modeling approaches, combined with experimental model parameter determination, to generate the basis for any total process optimization by simulation. As an example the extraction of target compounds from wood is chosen.


Computer-aided chemical engineering | 2007

Modeling of counter current monoclonal antibody extraction using aqueous two-phase systems

Joachim Ahmed Samatou; Annebart Engbert Wentink; P.A.J. Rosa; Ana M. Azevedo; M.R. Aires-Barros; Werner Bäcker; Andrzej Górak

Abstract Design of chemical processes is usually based on rigorous modeling of unit operations. Unfortunately, the use of physically grounded models in biotechnological applications is rare since their design is mainly based on heuristics and experiments. In this work a computer aided design method is presented for modeling of aqueous two-phase extraction of monoclonal antibodies (MAbs). A conventional counter current extractor is compared with a fractional extractor in terms of purity and concentration of MAbs in the extract. The purity of MAbs increased from 85% in the conventional to almost 100% in the fractional extractor.


Chemical Papers | 2008

Computer-aided process design of affinity membrane adsorbers: a case study on antibodies capturing

Peter van Beijeren; Peter Kreis; Achim Hoffmann; Martina Mutter; Sven Sommerfeld; Werner Bäcker; Andrzej Górak

Design of affinity membrane adsorbers for the purification of biomolecules requires a consideration of loading, washing, and elution. Modelling and simulation of membrane adsorbers in literature is, however, strongly focused on the loading step. Therefore, in this work, a complete process model which takes all the different steps into account was developed. Breakthrough experiments in which human IgG was captured onto and eluted from Sartobind Protein A downscale modules were used for model validation and for estimation of the required model parameters. The experimentally observed breakthrough curves were independent of the applied flow rate and from these results linear correlations between lumped kinetic parameters and linear velocity were determined. During elution, desorption was best described by an irreversible reaction of first order in H+ concentration. Applicability of the developed model to computer-aided design was illustrated through a process analysis study in which the influence of the amount of loaded protein per cycle on the process yield and productivity was investigated.


Biotechnology Advances | 2011

Aqueous two-phase extraction as a platform in the biomanufacturing industry: Economical and environmental sustainability

P.A.J. Rosa; Ana M. Azevedo; Sven Sommerfeld; Werner Bäcker; M.R. Aires-Barros


Journal of Biotechnology | 2009

Application of aqueous two-phase systems to antibody purification: a multi-stage approach.

P.A.J. Rosa; Ana M. Azevedo; Sven Sommerfeld; Martina Mutter; M.R. Aires-Barros; Werner Bäcker


Chemie Ingenieur Technik | 1998

Stoffaustausch-Messungen an Einzeltropfen und an Tropfenschwärmen in einer Gegenstrom-Meßzelle

Jürgen Schröter; Werner Bäcker; Manfred J. Hampe


Archive | 2007

Method for manufacturing aniline

Markus Dugal; Franz-Ulrich Gehlen; Stefan Wershofen; Andre Lago; Peter Lehner; Werner Bäcker; Benie Marotz; Horst Brinkschulte

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Ana M. Azevedo

Instituto Superior Técnico

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P.A.J. Rosa

Instituto Superior Técnico

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Andrzej Górak

Technical University of Dortmund

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Jochen Strube

Clausthal University of Technology

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M.R. Aires-Barros

Instituto Superior Técnico

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