Marine sponges are rich in microbial biota. In this study, totally four sponges namely Callyspongia diffusa, Hyattella Cribriformis, Sigmadocia carnosa, Spongia officininalis Var ceylonensis were collected and their associated bacteria and fungi were isolated. Among the microbes isolated, Pseudomonas fluorescens and Penicillium citrinum were isolated from C. diffusa which showed broad range of activity against tested pathogens. This study demonstrates that the culturable fraction of bacteria and fungi from the sponges were diverse and appears to possess much potential as a source for the discovery of new medically relevant biological active agents.

Melanin pigments are frequently used in medicine, food and cosmetic preparations. In this study, three strains among 21 Actinomycetes sp isolates produced a diffusible dark pigment on starch casein an agar medium which was water soluble. The pigment production was estimated using L-tyrosine as substrate. Among the strains, 3 (F1, F2, F3) were used for further analysis. Optimized culture condition for melanin production were; 1% of starch-best carbon source, 0.2% of soyabean-best nitrogen source, salinity-15 ppt, temperature-35°C, pH-7.0 and incubation time-168 h. Sugarcane waste was found to be the cheaper and best source for melanin production. Melanin also showed activity against potential pathogens. The maximum antimicrobial activity was observed with Escherichia coli (20 mm) and Lactobacilus vulgaris (20 mm). F1 strain producing melanin was taken for FT-IR analysis. The FT-IR result confirmed that it was melanin pigment. Therefore, this study proved that sugarcane waste can be used for the production of melanin and it (melanin) has potential anti-bacterial activity.

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There is a need for new drugs especially novel antibiotics, anticancer compound, antibiotic against multi drug-resistant bacteria. The discovery and development of new drugs from marine microbes played a significant role over the last few decades. The world oceans comprise a rich diversity of microbial life with current estimates reaching over a million different species. Marine microbes are important from both ecological and biotechnological point of view. Marine microbial bioactive compounds have attracted increasing attention from microbiologists, taxonomists, ecologists, agronomists, chemists and evolutionary biologists.

New applications of nanomaterials are rapidly emerging. The synthesis of nanoparticles is a cornerstone of nanotechnology. Microbial cells are highlyorganized units, regarding morphology and metabolic pathways, capable of synthesizing well size-calibrated and well-structured particles. Furthermore, biogenic nanoparticles often are water-soluble and biocompatible, which is essential for many applications. Molecular identification of a novel strain P. fluorescens BCPBMS-1 from sponge Callysspongia diffusa (Mandapam Coast) through 16s rRNA ribotyping (Gen bank accession number: HQ907732). The silver nanoparticles were analyzed by UV-Visible spectroscopy. Their chemical composition was determined by FT-IR spectroscopy. SEM observationrevealed that silver nano particles are having spherical shape. The antibacterial activities of silver nanoparticles were screened against common human pathogen Escherichia coli, Proteus mirabilis, Salmonella typhi, Salmonella paratyphi, Vibrio cholerae, Klebsiella oxytoca, Klebsiella pneumoniae and Staphylococcus aureus. Among these 5mm antibacterial activity was observed with E. coli, 4mm with P. mirabilis and S. typhi, 3mm activity was observed with S. paratyphi. These results suggest that Ag nanoparticles can be used as effective growth inhibitors in various microorganisms, making them applicable to diverse medical devices and antimicrobial control systems.