Thermodynamic Modeling for Protein Extraction in Water - PEG 8000 - Dextran 75 System using MATLAB

This report basically discusses the research done and basic understanding of the
chosen topic, which is Thermodynamic Modeling for Protein Extraction inAqueous
Polymer System. The objective ofthe project is to study on extending the application
of polymer thermodynamic model, namely Flory-Huggins Theory [1,2], to capture
and predict the partitioning behaviour of a sample of different types of proteins in an
Aqueous Two-Phase Extraction System (ATPES). ATPES is a liquid-liquid extraction
technique that can be applied as a protein separation method. At equilibrium, these
systems form water-rich two liquid phases which a target protein selectively partitions
into one of the phases according to its ATPES' characteristics. The protein
partitioning behavior can be captured using the above mentioned thermodynamic
model. Examples oftwo-phase systems are either two polymers (e.g., PEG/dextran)
or one polymer in high-salt concentration (e.g., PEG/salt). The scope for this project
will be the protein extraction in aqueous polymer system. To observe the efficiency of
ATPES to extract certain types ofproteins, a modeling approach by Ahmad [3] based
on MATLAB will be used. Using MATLAB software as a helping hand, equilibrium
compositions and the partition coefficient of a target protein in the system can be
computed. The model will be used to analyze the variations in the partitioning trends
and patterns for different types ofproteins. The results will be the partitioning ofthe
respective target proteins, either to the top or to the bottom phase in the ATPES,
producing partitioning coefficient ofgreater or less than the value of1respectively. In
this report, the equilibrium compositions and the partition coefficient of human
hemoglobin and lysozyme from chicken egg white in water - PEG 8000 - Dextran 75
system are calculated using the modeling approach by Ahmad [3]. The result obtained is
then compared to empirical data [30].