1520-6033/asset/BTPR_left.gif?v=1&s=a5be2ff5a0fe6ccdaad74a6d128c142e5f71a8da)
1520-6033/asset/BTPR_right.gif?v=1&s=992d113a3e61fc9d3571812359165df86cf830e4)
Bioseparations and Downstream Processing
Correlation of second virial coefficient with solubility for proteins in salt solutions
Article first published online: 14 OCT 2011
DOI: 10.1002/btpr.724
Copyright © 2011 American Institute of Chemical Engineers (AIChE)
Additional Information
How to Cite
Mehta, C. M., White, E. T. and Litster, J. D. (2012), Correlation of second virial coefficient with solubility for proteins in salt solutions. Biotechnol Progress, 28: 163–170. doi: 10.1002/btpr.724
Publication History
- Issue published online: 2 FEB 2012
- Article first published online: 14 OCT 2011
- Accepted manuscript online: 9 SEP 2011 07:59AM EST
- Manuscript Revised: 30 AUG 2011
- Manuscript Received: 23 MAY 2011
Funded by
- ARC and a scholarship from the School of Engineering, The University of Queensland
- Abstract
- Article
- References
- Cited By
Keywords:
- solubility;
- osmotic second virial coefficient;
- ovalbumin;
- lysozyme;
- α-amylase
Abstract
In this work, osmotic second virial coefficients (B22) were determined and correlated with the measured solubilities for the proteins, α-amylase, ovalbumin, and lysozyme. The B22 values and solubilities were determined in similar solution conditions using two salts, sodium chloride and ammonium sulfate in an acidic pH range. An overall decrease in the solubility of the proteins (salting out) was observed at high concentrations of ammonium sulfate and sodium chloride solutions. However, for α-amylase, salting-in behavior was also observed in low concentration sodium chloride solutions. In ammonium sulfate solutions, the B22 are small and close to zero below 2.4 M. As the ammonium sulfate concentrations were further increased, B22 values decreased for all systems studied. The effect of sodium chloride on B22 varies with concentration, solution pH, and the type of protein studied. Theoretical models show a reasonable fit to the experimental derived data of B22 and solubility. B22 is also directly proportional to the logarithm of the solubility values for individual proteins in salt solutions, so the log-linear empirical models developed in this work can also be used to rapidly predict solubility and B22 values for given protein–salt systems. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2012