Photocollection

Production of recombinant proteins in Staphylococcus carnosus

Secretion to the culture medium or immobilization on the cell surface

Novel protein therapeutics such as growth factors, protein hormones and enzymes are at present almost exclusively produced in the well characterized coli bacteria. At the Institute for Microbial Genetics an alternative system based on the non pathogenic food-grade bacterium Staphylococcus carnosus is developed. In contrast to Coli-bacteria, S. carnosus is able to secrete large amounts of proteins to the culture supernatant. The proteins can thus be isolated in soluble and relatively pure state. Laborious solubilization, renaturation and purification procedures, which often strongly reduce the product recovery in E. coli are dispensable in S. carnosus . The almost complete absence of proteolytical activities and the high genetic stability are further advantages of the S. carnosus system.

In previous studies the ability of S. carnosus to produce and secrete proteins was analyzed and optimized. Besides several hydrolytic enzymes human and mammalian growth factors have been produced.

Proteins can be covalently anchored to the staphylococcal cell wall by means of a C-terminal recognition sequence. Various enzymes could thus be immobilized on the surface of S. carnosus in an active conformation. Furthermore, by anchoring protein domains of pathogenic microorganisms a great variety of antigens can be presented on the bacterial cells. Based on the nonpathogenic S. carnosus, oral applicable live vaccines, directed for example against hepatitis viruses shall be developed by this method.