摘要:

AbstractAs more and purer complex pharmacological proteins such as factor VIII, erythropoietin, colony stimulating factors, human growth factors, interferons, interleukins, monoclonal antibodies, and plasminogen activators need to be produced, increasing attention will be devoted to their recovery. In this brief review we focus on the molecular properties of proteins that are commonly exploited for their bioseparation. A formalism is then presented illustrating how structure (primary through quartenary) defines the properties of a protein and hence establishes the dominant interactions that determine the most appropriate group of separation processes that need to be considered for the recovery of the desired protein. A detailed example is used to illustrate this for electrostatic interactions during the adsorption of ribonuclease A onto mica. The paper concludes with the assertion that recombinant DNA techniques will play an increasingly important role in protein separations. These methods are already being used to increase the concentration and purity of a desired heterologous protein. Excretion of foreign proteins from the cytoplasmic space of E. coli into the medium is now a reality. Polypeptide marker fusion systems have also been used to facilitate excretion, purification, and identification of a desired protein. Clearly, combining rDNA techniques with biospecific affinity interactions augurs well for the future of efficient and highly selective separation processes.

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930903

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1989

数据来源: WILEY

摘要:

AbstractDownstream processing in biotechnology is best idealized as a four step process: removal of insolubles, isolation, purification, and polishing. The first and last steps are relatively easily achieved; the isolation and purification steps include most of the potential problems. While purification has often been presumed the most difficult, isolation may involve the greatest cost, presumably because it involves getting a small volume of concentrate from a large volume of feed. Both purification and isolation can sometimes use hollow fibers for extraction and chromatography.

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930904

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1989

数据来源: WILEY

摘要:

AbstractWhen confronted with the chromatographic separation of proteins one often has to cope with a large number of parameters which have either been set by the producer or oneself and which in many cases are only poorly understood. Therefore in this paper some of the fundamentals involved in the mechanism of protein adsorption on alkyl‐substituted gel surfaces will be treated. Although a large number of papers have been published on protein adsorption there is no general theory on the adsorption mechanism. The possibility of synthesizing surfaces for adsorption in a controlled way on hydrophilic gels has become feasible after the introduction of affinity chromatography. Since this technique has allowed the elucidation of a number of general mechanistic principles involved in the protein adsorption process and the corresponding sorption kinetics these results will be primarily discussed her

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930905

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1989

数据来源: WILEY

摘要:

AbstractThe paper presents a short review on the application of aqueous two‐phase systems, based on incompatible polymer pairs, for the fractionation of biopolymers by a liquid/liquid partition chromatography technique. In the development of this technique the problem of immobilizing one of the two phases on a support was solved by either using support materials incompatible with one of the two phase‐forming polymers, or by grafting water‐soluble linear polymers with such incompatibility properties on hydrophilic support particles. In both cases, the support particles repel that phase of the phase pair which is rich in the incompatible polymer and are wetted selectively by the second one which consequently forms the stationary phase in the column packing. — Among the aqueous two‐phase polymer system known, the polyethylene glycol (PEG)/dextran (Dx) system is the most common one. Since PEG is incompatible with cellulose and polyacrylamide, the Dx‐rich phase forms the stationary phase in columns prepared from these materials. The same holds for support particles on which linear polyacrylamide chains are fixed by a graft polymerisation. The capabilities of such columns for separating proteins and nucleic acids is documented by so

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930906

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1989

数据来源: WILEY

摘要:

AbstractAn overview of the three major operational modes of chromatography — frontal, elution and displacement — is presented with emphasis on their application to the preparative purification of biopolymers. The theoretical basis of the techniques is discussed and some of their features are illustrated with the help of computer simulated chromatogr

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930907

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1989

数据来源: WILEY

摘要:

AbstractIn affinity partitioning the effectivity of purification is a function of the number of binding sites of the protein and the dissociation constant of the ligand/protein complex. To design an optimal purification process a mathematical model has been developed. Taking formate dehydrogenase from Candida boidinii as an example these data were evaluated in single stage experiments and could be confirmed by affinity partition chromatography.

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930908

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1989

数据来源: WILEY

摘要:

AbstractThe separation of intracellular enzymes from disintegrated microbial cells is one of the most crucial steps in enzyme production. One way to overcome this problem is the application of physical extraction in polymer/salt based aqueous phase systems. An alternative, more recent approach being still under investigation is reactive extraction — called affinity partitioning/extraction in biotechnology — carried out in aqueous two‐polymer phase systems.In the intended contribution affinity extraction will be discussed with regard to the— physico‐chemical basis and general potential• parameters influencing affinity partitioning• modeling• selectivity• product yield• ways to improve performances• “product elution”/product separation from the ligand• limitations• comparison with physical extraction and— technical aspects• scale‐up• ligand recycling• continuous processing• economicsThe presentation will be based on recent literature data and several process examples being prese

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930909

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1989

数据来源: WILEY

摘要:

AbstractReactive extraction of special metabolites is of interest, since the technique can provide higher distribution coefficients than pure physical extraction. In addition, very polar carboxylic acids can only be extracted by using extractants such as organophosphorus compounds or high molecular weigth amines. In this paper, the extraction of typical metabolites such as penicillin G and α amino acids is discussed in regard to the nature of the extractant and modifier used

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930910

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1989

数据来源: WILEY

摘要:

AbstractThe common precipitation process for the isolation of citric acid produces 2,5 tons of waste per ton citric acid. This paper presents a way to separate citric acid from a fermentation broth by avoiding the waste production of CaSO4. A combination of an extraction/reextraction process using a tertiary‐amine‐containing solvent was develo

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930911

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1989

数据来源: WILEY

摘要:

AbstractUnit operations with intrinsic chemical reactions, like solvent extraction (SX) and liquid membrane permeation (LMP), offer the possibility to design selective separation processes. Ion exchanger types used for downstream processing are discussed. The influence of chemical parameters on the separation of an amino acid (1‐phenylanaline) is shown as an example. A comparison of LMP and SX technique is given with emphasis on the difference of mass transfer mechanism and devices neede

ISSN:0005-9021    

DOI:10.1002/bbpc.19890930912

出版商:Wiley‐VCH Verlag GmbH&Co. KGaA    

年代:1989

数据来源: WILEY