Improved bioseparation techniques are increasingly important for biotechnology because
downstream processing accounts for a major share of the production cost. Several processes do not become
commercially feasible for this reason involved in the purification protocols (50-90% of the final
product cost). Downstream processing poses several problems mainly because of two reasons (1). Target
biomolecule or compound is generally present in dilute form and (2). It is present along with several
other undesired compounds, needing a chain of purification steps to obtain the desired product in
the required purity as well as concentration. Hence there is a need for efficient and economically feasible
downstream processing methods. Aqueous Two Phase Extraction is one such method which offers several advantages
such as biocompatibility (due to presence of high water content), ease of scale-up and scope for continuous operation. In
ATPE, equipment used in the conventional organic extraction in the chemical industry (e.g., spray, packed column, etc.)
can be adapted easily when multistage procedure is needed and the phase separation is achieved in these contactors by
gravity separation, thereby eliminating the need of expensive equipments. In spite of having so many advantages, ATPE
method did not realize the wide commercial adoption that it richly deserves, due to several factors. In the present review,
special emphasis is given to different equipments employed for ATPE both at large and lab scales, besides attempting
analysis of equipment design parameters of these equipments along with operational conditions that affect their performance.
This review also attempts to present major advantages and challenges faced for the industrial adoption of the technique.