Merits of secretion of heterologous proteins from industrial microorganisms.

The heterologous expression of proteins is without doubt one of the most fascinating applications of the recombinant DNA technique. Despite clear successes many attempts to produce a certain protein in a heterologous host cell have met with technical difficulties. Secretion from cells has been used as a solution to overcome the intracellular formation of inactive protein. Microorganisms with a history of use in the fermentation industry exhibit clear advantages over the frequently used Escherichia coli as host cells for secreted products. Interleukin-3, chymosin and phytase are examples of commercial products that are produced efficiently with the aid of industrial microorganisms.