Study of Human Insulin Synthesis and Purification Methods

Human insulin was the first mammalian protein produced in bacteria using recombinant DNA technology.Two technologies were developed: the first based on the separate expression of precursors of chain A and B of insulin, and the second based on the expression of a precursor of proinsulin as a Trp-E fusion protein. Both technologies utilized Escherichia coli as an expression system. Later, a third technology was developed based on a strain of yeast that can secrete a precursor of insulin. The second E.coli process, a variation of which has been commercialized by Eli Lilly and Co., is analyzed in this article from a process design evaluation viewpoint. The plant analyzed in this article has a capacity of around 1,800 kg or purified BHI per year. This represents a relatively large plant for producing polypeptide-based biopharmaceuticals. A purification process based on multimodal chromatography, which exploits differences in molecular charge, size, and hydrophobicity, is typically used to isolate the human insulin. A detail description of all the purification steps follows. The purification of the insulin solution proceeds with a reverse phase high-pressure-liquid-chromatography (RP-HPLC) step. Detailed information on the use of RP-HPLC for insulin purification is available in the literature. Analytical studies with a variety of reversed-phase systems, have shown that an acidic mobile phase can provide excellent resolution of insulin from structurally similar insulin-like components.