3. Improvement through strain modification

Improvement strategies aim to increase final product concentration and reduce the production of undesirable cometabolites. Considerations such as how the producing strains are used are also taken into account. Two broad categories of approaches are used for breeding: random mutagenesis and metabolic engineering (figure 4 ).

Random mutagenesis requires no prior knowledge of either the genome or the physiology of the treated strains. Mutagenesis induces genetic changes within the genome, without any a priori knowledge of their location.

Metabolic engineering can be defined as the improvement of a cell's...