Acoustic field assisted enhanced demixing of aqueous two-phase systems.

Srinivas, N. D. and Barhate, R. S. and Raghavarao, K. S. M. S. and Todd, P. (2001) Acoustic field assisted enhanced demixing of aqueous two-phase systems. Biochimica et Biophysica Acta, 1524 (1). pp. 38-44. ISSN 0006-3002

PDF Biochimica et Biophysica Acta (BBA) - General Subjects, Volume 1524, Issue 1, 15 November 2000, Pages 38-44.pdf - Published Version Restricted to Registered users only Download (225kB)

Abstract

Aqueous two-phase extraction has been recognized as a versatile downstream processing technique for the recovery of biomolecules. A major deterrent to its industrial exploitation is the slow demixing of the two aqueous phases after extraction, due to their similar physical properties. A method to decrease the demixing times of these systems, employing a travelling acoustic wave field, is reported. The effects of phase composition and microbial cells on demixing in a polyethylene glycol/potassium phosphate two-phase system are studied in detail. As phase composition increased, demixing time decreased gradually. Phase volume ratio was found to have a significant effect on demixing time at low phase compositions. However, at intermediate and high phase compositions, only a small effect on demixing time was observed. The effect of phase composition and volume ratio on demixing behavior was explained based on the droplet size of the dispersed phase, which is the resultant effect of the physical properties of the phases. At all the phase compositions studied, the acoustically assisted process decreased the demixing time by 17-60% when compared to demixing under gravity alone. Increasing the cell concentration increased the demixing time markedly in case of yeast cells. However, it remained practically constant in the case of Lactobacillus casei cells. Application of an acoustic field reduced the demixing times up to 60% and 40% in the case of yeast and L. casei cells, respectively. Visual observations indicated that ultrasonication caused mild circulation currents in the phase dispersion enhancing droplet-droplet interaction, which in turn enhanced the rate of coalescence, eventually resulting in an enhanced demixing rate.

Item Type:	Article
Uncontrolled Keywords:	Aqueous two-phase extraction; Coalescence; Demixing time; Microbial cell ; Acoustics
Subjects:	600 Technology > 08 Food technology > 07 Food Engineering
Divisions:	Food Engineering
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	25 May 2012 04:27
Last Modified:	25 May 2012 04:27
URI:	http://ir.cftri.res.in/id/eprint/2144

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