Serratia marcescens C3 produces a natural red-pigment, prodigiosin, which exhibits immunosuppressive
properties, in vitro apoptotic effects, and in vivo anti-tumor activities. This work seeks to improve the
production of prodigiosin by S. marcescens C3 using various strategies. Starch and peptone were identified
as the optimized carbon and nitrogen sources for the production of prodigiosin, yielding a prodigiosin
concentration of 2.3 g/L. This value was significantly increased to 6.7 g/L using a carbon/nitrogen ratio
of 6/4 (starch/peptone = 16 g/L/10.67 g/L). To enhance prodigiosin production even further, a statistical
experimental design methodology was utilized to optimize the composition of the culture medium that is
utilized in the production of prodigiosin. Prodigiosin production of 7.07 g/L was achieved when the concentrations
of two trace compounds, FeSO4·4H2O and MnSO4·4H2O, were optimized using the statistical
experimental design methodology. Their optimal concentrations were 0.56 mM and 3.25 mM, respectively.
Ultimately, the production of prodigiosin was increased from 2.3 g/L to 15.6 g/L, or by a factor of
nearly seven by immobilizing microorganisms in 3% calcium alginate beads.