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Use of aqueous two-phase systems for recovery and purification in biotechnology

Aqueous two-phase systems are generated by mixing aqueous solutions of two water-soluble polymers, or a polymer and a salt. These systems offer extremely mild conditions for separation of cells, organelles, proteins and other biomolecules, in biochemical processes. Considerable attention has been directed towards the use of the two-phase systems in several areas of biotechnology. The present paper

Affinity precipitation

Precipitation and recovery of precipitates is one of the unit operations in chemical engineering that can be operated on a large scale. Experiences from the area of biotechnology have clearly shown that there is not enough selectivity in the precipitation methods used to be able to separate, for example, complex mixtures of proteins from cell homogenates. Moreover, methods to precipitate proteins

Affinity ultrafiltration for protein purification

Purification of a biochemical product from fermentation broths or other complex biological mixtures generally involves a combination of techniques which resolve substances according to differences in their physicochemical properties. These techniques have traditionally been optimized individually rather than as a part of the integrated, continuous process. Moreover, a lot of the development and re

Single-step partitioning in aqueous two-phase systems

Partitioning in aqueous two-phase system (ATPS) provides a rapid and gentle means of separation of soluble as well as particulate biomaterials, e.g. proteins, nucleic acids, cells, viruses, organelles, and membranes. Partitioning between the two phases is a complex phenomenon, guided mainly by the interaction of the partitioned substance and the phase components, e.g., through hydrogen bonds, van

Integration of extraction with affinity precipitation

Conventional aqueous two-phase extraction by spontaneous partitioning has often problems with low specificity. The introduction of an affinity ligand into one of the phases has been attempted to enhance the specificity of protein partitioning (1-7; Chapters 29-31). However, this procedure still has some limitations in the effective removal of impurities as well as recovery and reuse of the ligand.

Structure and high photocatalytic activity of (N, Ta)-doped TiO2 nanoparticles

A hydrothermal method was used to prepare three nano-crystalline samples of TiO2 (S1), N-doped TiO2 (S2), and (N, Ta)-codoped TiO2 (S3) with average crystallite sizes (D) of 13-25 nm. X-ray diffraction studies confirmed a single phase of the samples with a tetragonal/anatase structure. A slight increase in the lattice parameters was observed when N and/or Ta dopants were doped into the TiO2 host l