Aqueous Two Phase Systems

A mixture of two polymers, or one polymer and a salt, in an aqueous medium separates into two phases: this phenomenon is useful in biotechn- ogy for product separations. Separation of biological molecules and particles in these aqueous two-phase systems (ATPS) was initiated over 40 years ago by P.-Å. Albertsson, and later proved to be of immense utility in biochemical and cell biological research. A boost in the application of ATPS was seen when problems of separations in biotechnology processes were encountered. Its simplicity, biocompatibility, and amenability to easy scaleup operations make the use of ATPS very attractive for large-scale bioseparations. Despite the advantages ATPS enjoys over other separation techniques, the application of two-phase systems has for a long time been confined to selected labora- ries. Recent years have, however, shown a trend in which increasing numbers of researchers employ two-phase partitioning techniques in both basic and applied research.

This comprehensive and unique text presents a full overview of downstream processing useful for those new to the concept as well as professionals with experience in the area. The history and theoretical principles of Aqueous Two-Phase Systems (ATPS) are covered in depth. Information on ATPS characterization and application is included, and ATPS equilibria and system parameters that have significant effect on partition behavior are studied. Aqueous Two-Phase Systems for Bioprocess Development for the Recovery of Biological Products addresses specific applications of ATPS for the recovery and partial purification of high molecular weight compounds such as proteins, nucleic acids and polysaccharides, particulate bioproducts such as cells and organelles and low molecular weight compounds. Non-conventional strategies involving ATPS such as affinity systems, continuous liquid-liquid fractionation stages and the recovery from plant extracts are presented. Economic analysis of the application of ATPS in comparison to other fractionation techniques, particularly liquid chromatography, is considered, as are opportunity and current trends in the ATPS research area. Each chapter utilizes the contributors' experimental expertise in traditional and non-conventional ATPS strategies, as well as analysis of areas of opportunity and perspectives on the development and future applications of ATPS in both the lab and larger scale operations. The result is a thorough and singular overview of ATPS which has not been matched by any other text on the market.

Partitioning in Aqueous Two-Phase Systems: Theory, Methods, Uses, and Applications to Biotechnology is a collection of papers that discusses the applications of aqueous two-phase systems to problems of separation and extraction of macromolecules, organelles, and cells. Papers focus on the theoretical basis and the practical details of the procedures used. Some of the papers describe in one or a few steps how two components can be separated by the investigator manipulating their partitions so that one component is in one phase and the other component is in the other phase or at the interface. Investigators can also avail of developed batch extractions for plant organelles, cell membranes, nucleic acids, and proteins. The book cites as an example the partitioning of right-side-out and inside-out vesicles (obtained from fragments of thylakoid membranes) to the top and bottom phases, respectively, of a Dx-PEG system. Other papers describe the use of the countercurrent distribution when single extraction steps are not sufficient to produce a separation in materials that do not differ greatly in their partitioning behavior. The collection can prove valuable for bio-chemists, cellular biologists, micro-biologists, and developmental biologists.

Aqueous Two-Phase Systems (ATPS) have been used since their discovery for the isolation of a large number of different biological materials, such as animal and plant cells, microorganisms, viruses, cellular organelles such as chloroplasts, mitochondria, membrane vesicles, and also in the purification of proteins and nucleic acids. In Aqueous Two-Phase Systems: Properties, Functions and Advantages, the authors begin by discussing the benefits of these systems.The following chapter presents the main forms of the purification of lipases from aqueous biphasic systems, addressing and discussing the fundamentals for the formation, use and optimization of these systems applied in the biotechnological context. The authors address the basis of aqueous-biphasic systems, aqueous two-phase systems for enzymatic purification, purification of lipases and combined uses of aqueous two-phase systems.The most important experimental parameters that affect the efficiency of metal ions extraction in aqueous PEG-based two-phase systems are examined to provide a starting point in the design of a suitable system for the extraction of metal ions. Compared to the conventional solvent extraction, which uses toxic, flammable and volatile organic solvents and can be quite expensive, the extraction in aqueous PEG-based two-phase systems is considered a more environmental friendly and economically viable method.Also in this compilation, an overview about application of ATPSs in microstructured devices is provided. Microstructured devices offer potential benefits due to well-defined high specific interfacial areas available for heat and mass transfer. These areas increase transfer rate and enhance yield, selectivity and process control. The application of ATPSs in Micro Total Analysis Systems is described as well.

Rajni Hatti-Kaul and her expert coauthors combine theory, methodology, and applications in a practical collection of easily reproducible protocols for bioseparations in aqueous two-phase systems (ATPS). The protocols range from established methods to cutting-edge techniques with potential biotechnological applications. Among the methods detailed are those for ATPS preparation and characterization, for partitioning applied to soluble molecules and particulates (including whole cells, membranes, and organelles), and for the isolation and purification of proteins - including a glimpse of large-scale handling of two-phase separations. Practical and informative, with its detailed guidelines allowing researchers to adapt specific systems to their own separation needs, Aqueous Two-Phase Systems: Methods and Protocols demonstrates the scope and utility of two-phase aqueous systems in both basic and applied research.

General methodology and apparatus: phase diagrams, preparation and analysis of two-phase systems, partioning and affinity partitioning of macromolecules: Proteins, nucleic acids, studies on protein interactionsmolecular structure, charge, hydrophobicity, and conformational chan ges, partitioning and affinity partitioning of particulates,organellesseparation and subfractionation, menbrane: separation and subfractionation, membrane domain analysis, aqueous phase separation in biologicalsystems, aqueous two-phase systems in large-scale process biotechnolo gy, proteins; downstream processing, design of proteins for enhanced extraction, other applications of aqueous phases in biotechnology. Enzymology.

This book offers comprehensive information on the fundamentals and applications of ionic-liquid-based aqueous biphasic systems, which have predominantly (and successfully) been employed as alternative platforms for the extraction, separation and purification of diverse high-value products. The book consists of an initial introduction providing a brief overview, from fundamentals to applications, followed by nine chapters addressing the respective phase diagrams (interpretation and characterization) and remarkable examples of their applications. It also includes two final chapters focusing on recent developments in the search for more environmentally-benign and biocompatible ionic-liquid-based aqueous biphasic systems, and on the progress made to date concerning the recovery, recycling and reuse of the phase-forming components, the goal being the development of cost-effective and sustainable processes. The book offers an interesting and useful guide for a broad readership in the fields of green chemistry, biotechnology, chemical engineering, and biochemistry, among others. Mara G. Freire is a Coordinator Researcher at CICECO - Aveiro Institute of Materials, Chemistry Department, University of Aveiro, Portugal.

Describes partition techniques for the separation and purification of cells, cell organelles, membrane vesicles, viruses, and biopolymers, such as proteins and nucleic acids. The basic theory of partition is discussed, as are the properties of aqueous, two-phase systems and the general behavior of particles and molecules. Updates include advances and new applications introduced since 1971.