Inhibitory Activities of Surface Associated Bacteria Isolated from the Marine Sponge Pseudoceratina purpurea

Abstract

The effects of four strains of Gram positive bacteria (PS2, PS9, PS11, and PS79) isolated from the sponge Pseudoceratina pupurea on the growth of a set of fouling bacteria and standard strains of genera Vibrio-Photobacterium were examined. Using a paper disc diffusion method, 4 sponge isolates were found to have inhibitory activity against 4 of 12 isolates of the fouling bacteria. All of the four bacterial supernatants also showed inhibitory activity against Vibrio alginolyticus and V. fischeri, while sponge extracts inhibited every strain tested. Phylogenetic analysis using 16S rRNA gene sequences revealed that three of the sponge isolates (PS2, PS9 and PS79) belonged to the genus Bacillus and one (PS11) belonged to the genus Virgibacillus. The isolation of strains possessing inhibitory activity against fouling bacteria suggests that sponge-associated bacteria could be potential sources of novel natural products.