PILOT-SCALE VERIFICATION OF A COMPUTER-BASED SIMULATION FOR FRACTIONAL PROTEIN PRECIPITATION

The development and experimental verification at pilot scale of a suit e of models for the batch precipitation by two-cut ammonium sulphate s alting-out of total protein and alcohol dehydrogenase from yeast homog enate is presented. The model consists of two elements: protein and en zyme solubility prediction and precipitate phase particle property pre diction. An isotherm-based approach has been used successfully to desc ribe solubility behaviour for a range of operating conditions typical of those obtained at a process scale. Estimation of the precipitate ph ase particle size distributions has been achieved through a discretize d population balance approach using simplified terms to account for pa rticle breakage and aggregation. The developed model accounts for the effects of average shear rate and residence time in the precipitation vessel across a two orders of magnitude range of scale. The size-densi ty relationship for the precipitate phase has been defined. Results of simulations are compared with pilot scale verification data to confir m the validity of the models developed.