A bioprocess was developed for the production of l-leucine aminopeptidase under solid-state fermentation (SSF) by cultivating Streptomyces gedanensis in an inert support impregnated with a minimal medium. Response surface methodology of Box Behnken design was used to derive the optimum level of significant factors (3 ml inoculum (1.2 x 10(9) CFU/ml); 0.275% w/v (NH4)(2)SO4; 0.275% w/v MgSO4 center dot 7H(2)O and 0.55% w/v Tryptone) for maximum LAP production (489 IU/g PUF) as compared to the initial level of 176.3 +/- A 0.02 IU/g PUF. The high level of extracellular aminopeptidase yield achieved in this work showed the technical feasibility of LAP production under SSF using inert support and is the first report of this kind. The ability of Streptomyces amino peptidase to release particular N-terminal amino acids made them interesting for controlling the degree of hydrolysis and flavor development for a wide range of substrates in food like industries.