Melting Properties of Amino Acids as an Access to the Solubility Modeling

Knowledge about the melting properties of biomolecules is extremely important for process design, as such data influence
the solubility behavior in solvents, and such data are required for solubility modeling. However, melting properties for amino
acids were not accessible before this work because the amino acids decompose upon slow heating. By means of ’fast
scanning calorimetry’, a method that applies very high heating rates, the melting properties of 20 proteinogenic amino acids
were measured in this work. The new data were further used as an input data for thermodynamic modeling, which is used
to predict amino-acid solubilities in water. This is the maximum equilibrium amount of amino acid in the liquid phase at
defined temperature and pressure. The model prediction results were in very good agreement to the experimental solubility
data. The successful modeling results were accompanied by new experimental solubility data, pH measurements of the
liquid phase, and X-ray diffraction of the solid phase, which are important data to validate the model predictions.

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