Determination of lysozyme solubility by compressed time scale technique

Kitti Cherdrungsi, D. of Industrial Biotech., F. of Agro-Industry, PSU
. White, E. T., D. of Chemical Eng., The U. of Queensland, Australia
Johns, M. R., D. of Chemical Eng., The U. of Queensland, Australia
Corresponding e-mail : chkitti@ratree.psu.ac.th

Grant : Australian Government
Presented : The World Congress on Biotechnology and the 11th International Biotechnology Symposium and Exhibition, 3-8 September 2000, ICC, Berlin, Germany
Key words : lysozyme, solubility, compressed time, scale technique, crystallization

Bulk crystallization is widely used for recovery and purification of many materials both orga-nic and inorganic. Since the rapid advance in biotechnology and the increase in industrial demand, this technology should be considered for the recovery of large amount of high purity protein. Solu-bility data is an important tool for design and control in industrial crystallization. Determination of solubility data is fundamental to the understanding and study of nucleation and growth of crystals.

Solubility data can be determined by various methods, however crystallization and/or dissolution are widely being used. Both methods are time consuming processes especially for determination of protein solubility. Denaturation of protein and microbiological contamination are always of concern with long term study of protein solutions, which could affect the measured values. Solubility data may be estimated by suitable extrapolation plots. A possible approach is to plot lysozyme concentrations versus the log of time or inverse time, so called compressed time scale technique.

Lysozyme was selected as the protein for investigation of solubility by the compressed time scale technique. This paper shows the stages of the approach to equilibrium concentration of lysozyme in the slurry. The estimated values for lysozyme solubility are comparable to the values derived by the experiments in a long period of time.

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