The following conclusions can be drawn based on the work carried out to date.
The multistage electrophoretic extraction concept was shown to be capable of
electrokinetic transport of cells and particles.Although the depth of the chambers
hampers the resolution of cell extraction, studies to date have paved way for new
generation equipment. Resolution can be increased by decreasing the depth of the
chamber and increasing the diameter or cross sectional area of the chambers.
The heat transfer analysis presented here has led to the design of the next
generation of multistage electrophoretic separators. Two types of ADSEP could
be designed for the market:
1. An inexpensive version without temperature control, to be used with low
conductivity buffers.
2. A more expensive, thermostated instrument that can be used with high conductivity buffers.
3
Extraction of Macromolecules
The world market for industrial enzymes has been estimated at $1.2 billion in
1995 [76]. Production methods, such as fermentation of genetically engineered
microorganisms, have advanced tremendously in recent years. This has
promoted work on the development of macromolecule products such as
recombinant blood proteins, which require production on the multi-ton scale at
low cost (only a few dollars per gram) [77].
Generally many unit operations are used in combination, such as filtration
(normal or membrane), centrifugation, precipitation, crystallization, etc. for the
separation and purification of macromolecules. Chromatography in its various
forms (ion exchange, reversed-phase, hydrophobic interaction, affinity, and gel
filtration) has proved to be a general purification technique that can achieve the
desired product purity. Although individual unit operations for large-scale
purification of macromolecules are generally considered to be well developed
and satisfactory, the high degree of complexity (and large number) of steps
involved in a complete process are often a source of excessive cost and other
problems. Because of this, many of the recent developments in this field have
been directed at combining and eliminating different process steps [77].
In conventional methods like centrifugation, and even modern methods like
electrophoresis and column chromatography, scale-up problems are enormous,
making them uneconomical or prohibitively expensive unless the product is of
high value. Therefore there has been a need for alternative approaches to bioseparation problems.
Liquid-liquid extraction is one such method. This technology has been successfully used in separation of compounds in chemical and related industries for
many years. However, it is only recently that liquid-liquid extraction technology
has been recognized as potentially useful in biotechnology [78, 79]. Two classes
of two-phase extraction system are suitable for biomolecule recovery:
1. Aqueous two-phase systems (polymer-polymer type and polymer-salt
type).
170
K.S.M.S. Raghavarao et al.
The multistage electrophoretic extraction concept was shown to be capable of
electrokinetic transport of cells and particles.Although the depth of the chambers
hampers the resolution of cell extraction, studies to date have paved way for new
generation equipment. Resolution can be increased by decreasing the depth of the
chamber and increasing the diameter or cross sectional area of the chambers.
The heat transfer analysis presented here has led to the design of the next
generation of multistage electrophoretic separators. Two types of ADSEP could
be designed for the market:
1. An inexpensive version without temperature control, to be used with low
conductivity buffers.
2. A more expensive, thermostated instrument that can be used with high conductivity buffers.
3
Extraction of Macromolecules
The world market for industrial enzymes has been estimated at $1.2 billion in
1995 [76]. Production methods, such as fermentation of genetically engineered
microorganisms, have advanced tremendously in recent years. This has
promoted work on the development of macromolecule products such as
recombinant blood proteins, which require production on the multi-ton scale at
low cost (only a few dollars per gram) [77].
Generally many unit operations are used in combination, such as filtration
(normal or membrane), centrifugation, precipitation, crystallization, etc. for the
separation and purification of macromolecules. Chromatography in its various
forms (ion exchange, reversed-phase, hydrophobic interaction, affinity, and gel
filtration) has proved to be a general purification technique that can achieve the
desired product purity. Although individual unit operations for large-scale
purification of macromolecules are generally considered to be well developed
and satisfactory, the high degree of complexity (and large number) of steps
involved in a complete process are often a source of excessive cost and other
problems. Because of this, many of the recent developments in this field have
been directed at combining and eliminating different process steps [77].
In conventional methods like centrifugation, and even modern methods like
electrophoresis and column chromatography, scale-up problems are enormous,
making them uneconomical or prohibitively expensive unless the product is of
high value. Therefore there has been a need for alternative approaches to bioseparation problems.
Liquid-liquid extraction is one such method. This technology has been successfully used in separation of compounds in chemical and related industries for
many years. However, it is only recently that liquid-liquid extraction technology
has been recognized as potentially useful in biotechnology [78, 79]. Two classes
of two-phase extraction system are suitable for biomolecule recovery:
1. Aqueous two-phase systems (polymer-polymer type and polymer-salt
type).
170
K.S.M.S. Raghavarao et al.