Precipitation of porcine insulin with carbon dioxide

• Published in: Biotechnology and bioengineering 2009-08, Vol.103 (5), p.909-919
• Main Authors: Tashima, Alexandre Keiji, Ottens, Marcel, Van der Wielen, Luuk A.M, Cintra, Dennys E, Pauli, José R, Filho, Pedro de Alcântara Pessôa, Miranda, Everson Alves
• Format: Article
• Language: English
• Subjects: Aqueous solutions; Biological and medical sciences; Biotechnology; Carbon dioxide; Carbon Dioxide - metabolism; Carbonates - metabolism; Chemical Fractionation - methods; Chemical Precipitation; downstream; Fundamental and applied biological sciences. Psychology; Insulin; Insulin - isolation & purification; Isoelectric Point; Pharmaceuticals; Precipitation; solubility; Thermodynamics
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.22319

Recent works have pointed to the use of volatile electrolytes such as carbon dioxide (CO₂) dissolved in aqueous solutions as a promising alternative to the precipitating agents conventionally used for protein recovery in the food and pharmaceutical industries. In this work we investigated experimental and theoretical aspects of the precipitation of porcine insulin, a biomolecule of pharmaceutical interest, using CO₂ as an acid-precipitating agent. The solubility of porcine insulin in NaHCO₃ solutions in pressurized CO₂ was determined as a function of temperature and pressure, with a minimum being observed close to the protein isoelectric point. A thermodynamic model was developed and successfully utilized to correlate the experimental data. Insulin was considered a polyelectrolyte in the model and its self-association reactions were also taken into account. The biological activity of insulin was maintained after precipitation with CO₂, although some activity can be lost if foam is formed in the depressurization step. Biotechnol. Bioeng. 2009;103: 909-919.