RESUMEN
The objectives of present study are to extract the antibiotic compound from marine isolate and to determine its in vitro antimicrobial activity against bacteria. A marine bacterial isolate Serratia marcescens IBRL USM 84 was isolated from the surface of a marine sponge Xestospongia testudinaria. This species of bacteria produced red pigment with antibacterial activity. The red antibacterial pigment was produced intracellularly and inhibited 13 out of 18 tested bacteria, with Gram positive was more susceptible than the Gram negative bacteria. The growth and antibacterial red pigment production profiles demonstrated the highest antibacterial red pigment production was achieved at the 48 hours of cultivation (14.08 U/ml) time in marine broth when incubated at 25 °C with 150 rpm agitation. The antibacterial red pigment was extracted, purified and confirmed as prodigiosin.