Pigmented Pseudoalteromonas Sp. Isolated from Marine Sponge with Anti-Microbial Activities against Selected Human Pathogens

Marine sponges have been the potential source of bioactive compounds with potent antimicrobial properties. Sponge associated microbes significantly provide the route of biosynthesis of some of these compounds. In this work, a total of 100 bacterial colonies were screened from a marine sponge from Class Demospongiae, which has been collected from Merambong Island, the state of Johor, Malaysia. In disk diffusion assay, only 2 out of 100 isolates; namely C40 and C52, were able to demonstrate active inhibitions against selected human pathogens (Pseudomonas aeruginosa, Escherichia coli, Bacillus subtilis, except for Staphylococcus aureus). Isolates C40 and C52 were characterized to be Gram negative short rods, non-spore formers and catalase positive. Unlike the majority of other isolates from sponge which were Gram positive rods, Isolate C40 and C52 are Gram negative rods which grew in yellow pigmented colonies. Genotypic characterization using 16S ribosomal RNA sequencing were carried out on each isolate (accession number for C40 and C52 is MT645493 and MT645494, respectively). The 16S ribosomal RNA sequences revealed that these strains belonged to genus Pseudoalteromonas sp. with 97-98% similarities. Inhibitions studies showed that this sponge associated microorganisms potentially produce anti-microbial compounds useful for biotechnologies.