Researchers from the Helmholtz-Centre for Infection Research (HZI) in Braunschweig, Germany have developed a new method to cheaply produce insulin for the treatment of diabetes. The researchers wanted to develop a new procedure to increase the yield of an insulin precursor from which the actual insulin can be obtained, and in this way reduce costs. They found the yeast Pichia pastoris and modified the cells so that they produce the building block for insulin while growing on a special medium. The results were highly gratifying: “With our procedure, Pichia pastoris delivers high yields - twice as much as known before. Already with few cells it is possible to produce a lot of the insulin precursor,” says Ursula Rinas, from the HZI.
In the early 1980s, insulin was the first recombinant product approved by the FDA for human application. Today, human insulin is produced as recombinant protein, using two major routes. One route involves the production of the insulin precursor using the bacterium Escherichia coli as expression host with complex subsequent isolation, solubilisation and refolding procedures. The other route involves the well-known baker’s yeast Saccharomyces cerevisiae. The advantage of the latter route lies in the secretion of a soluble insulin precursor into the culture supernatant, making it easier for isolation and chemical modification. The newly described method from Ursula Rinas and her group also uses this route. The isolation of the precursor from the culture supernatant is only followed by enzymatic finishing. Insulin produced with this new method can be used normally and is identical to human insulin. The results have been published in the open access online research magazine Microbial Cell Factories.