The Effect of Media on the Prodigiosin Production of Entomopathogenic Bacteria Serratia marcescens Isolated from Brown Planthopper. Ifa Manzila, Tri P. Priyatno, Rahminovita Herlis, Iman Rusmana, I Made Samudra, and Yadi Suryadi. Prodigiosin, the red pigment produced by the bacterium Serratia marcescens, is a secondary metabolite of the family tripyrrole that has been widely used as an antibiotic in the multifunction treatment of antibacterial as well as antifungal. This study was aimed to study the effect of Luria-Bertani (LB) broth and nutrient broth (NB) media suplemented with several concentrations of FeSO 4 and CaCO 3 on the production and characteristic of prodigiosin derived from S. marcescens. The study was arranged in a completely randomized factorial design with four replications. The LB and NB media were supplemented with 0, 2.5, 5, and 10 mM CaCO 3 and 0, 0.25, 0.5, and 1 mM FeSO 4 . Results showed a red pigment produced by S. marcescens when cultured on both LB and NB media. Redlike pigmentation was varied when supplemented with different concentration of Fe 2+ and Ca 2+. The higher the concentration of Fe 2+ , the more intense the red color, conversely, the higher the concentration of Ca 2+ , the lighter the red color. The interaction was found between the media and concentrations of CaCO 3 and FeSO 4 on the production of prodigiosin. The highest prodigiosin production was obtained on NB media supplemented with FeSO 4 . Meanwhile, the addition of CaCO 3 did not affect the prodigiosin production. An addition of 1 mM FeSO4 to LB and NB media produced crude prodigiosin of 486.0 mg/ml and 489.0 mg/ml, respectively. Based on purification by column chromatography using silica gel, the prodigiosin production on LB and NB media was 378 mg/ml and 450 mg/ml, with the purity level of 77.8% and 92%, respectively. Detection of prodigiosin by thin-layer chromatography using silica gel showed the red pigment had Rf value of 0.83 and bioautography assay showed there was an antibacterial activity against Xanthomanas oryzae pv. oryzae. , semakin berkurang kepekatannya. Terlihat interaksi yang nyata antara media dan konsentrasi CaCO 3 dan FeSO 4 terhadap produksi prodigiosin. Konsentrasi prodigiosin yang tinggi diperoleh pada media NB yang ditambah FeSO 4 , sedangkan penambahan CaCO 3 tidak memberikan pengaruh sebaik FeSO 4 . Penambahan FeSO 4 1 mM pada media LB dan NB masing-masing menghasilkan 486,0 mg/ml dan 489,0 mg/ml prodigiosin ekstrak kasar. Berdasarkan hasil pemurnian dengan kromatografi kolom menggunakan gel silika, diperoleh prodigiosin murni pada media LB dan NB masing-masing sebanyak 378 mg/ml dan 450 mg/ml, dengan tingkat kemurnian 77,8% dan 92%. Deteksi prodigiosin dengan kromatografi lapis-tipis menggunakan gel silika menunjukkan pigmen merah mempunyai nilai Rf 0,83 dan hasil uji bioautografi menunjukkan adanya aktivitas antibakteri terhadap Xanthomonas oryzae pv. oryzae. Keywords