Creating Whole New Product and Reactants - Biosynthetic genes for secondary metabolites can also be transferred and expressed in a heterologous host, enabling it to produce novel products or reactants such as follows:

(i) Recombinant Streptomyces strains could be produced for production of antibiotics like mederrhodins A and B, dihydrogranatirhodin, 2-norerythromycinA, B, C and D and isovaleryl spiramycin,

(ii) New reactants may be produced in the form of new compounds.

These include transfer to E. coli, of naphthalene dioxygenase gene from Pseudomonas putida (for the synthesis of indigo), tyrosinase gene (for synthesis of melanin) from Streptomyces antibiotics and toluene, mono-oxygenase (for degradation of trichloroethylene, a widespread pollutant) from P. mendocina.