With the introduction of genetic engineering of Escherichia coli by Cohen, Boyer and co-workers in 1973, the way was paved for a completely new approach to optimisation of existing biotech processes and development of completely new ones. This lead to new biotech processes for the production of recombinant proteins, . the production of human insulin by a recombinant E. coli. With the further development in genetic engineering techniques the possibility ofto applying this for optimisation of classical fermentation processes soon became obvious, and advancements in genetic engineering allowed a far more rational approach to strain improvement than the classical approach of mutagenesis and screening,namely introduction of directed genetic changes.
