Identification, Phylogenetic Characterization and Preliminary Screening of Primary and Secondary Metabolites Producing Bacteria Associated with Marine Sponge Axinella donani

Sponges have pharmaceutical and medical relevance being known as a source of bioactive secondary products influencing antimicrobial, antiviral and cytotoxic activities. Study was undertaken on Axenella donani available of the coast of Kanyakumari. At Keelamanakudi village, adopting lobster catching technique fisherman netted these sponges yielding nearly 57 morphologically different bacteria. All the 57 isolates when screened showed proteolytic activity (7%), starch hydrolytic activity (12.2%), cellulolytic activity (3.5%). Broad spectrum antimicrobial activity was identified by using 16S rRNA sequencing. SEM examination helped to identify the sponges based on the diameter of the spicules (50 μm), exhibiting a tapered end present in them. Among the 57 isolates studied, two strains identified by 16S rRNA sequencing as Rhodobacter sphaeroides MSB 57 and Rhodopseudomonas palustris MSB 55 showed all the three bacteriolytic activities.