Identification of Metabolites - The initial screening is ordinarily done in plates using agar media. Subsequently, desirable isolates are screened in liquid cultures using shaker vessels. Shake cultures also allow the evaluation of different fermentation conditions, and are amenable to automated detection systems.

This step allows the identification of desirable isolates and the suitable culture conditions for them. In the next step, the cultures are scaled up to 10-70 litres; these cultures provide the material necessary for developing a suitable procedure for isolation of the active principle or compound of interest by trying out various solvents extraction procedures over a wide range of pH.