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The present study explores the antifouling potentials of ethanol extract of mangrove Avicennia officinalis. Results of antibacterial activity inferred that extract had strongly inhibited the growth of fouling bacterial strains with significant differences in halos (9-16 mm) and showed minimal bacteriostatic (12.5–100 µg ml−1) and bactericidal (25-200µg ml−1) values. It had also strenuously suppressed fouling microalgae with appreciable MIC (12.5 and 50 µg ml−1). The extract had also effectively deterred settlement of larvae of Balanus amphitrite and byssal thread of mussel Perna indica with lower EC50 (11.67 and 37.43 µg ml−1) and higher LC50 (257.33 and 817 µg ml−1) values. Further 100% recuperation of mussels from toxicity assay and therapeutic ratio of >20 substantiated its non-toxicity. GC-MS profile of bioassay guided fraction showed four (M1-M4) major bioactive metabolites. In silico biodegradability study revealed that metabolites M1 (Pentanoic acid, 5-methoxy-, phenyl ester) and M3 (Benzaldehyde, methyl-) have rapid biodegradation rates and eco-friendly in nature.

Marine bionanotechnology is one of the most promising areas of research in modern science and technology. Although there are multitude methods for the synthesis of nanoparticles (NPs), there is an increasing attention in developing high-yield, low-cost, non-toxic and eco-friendly procedures. The vital advantages of greener synthesis are cost-effective, reduced usage of toxic chemicals and abundant availability of resources. During the last ten years, there have been many biological entities used to elevate novel, greener and affordable methods for the metal NPs synthesis. Rate of synthesis and stability are higher for plant material mediated NPs. However, in comparison with terrestrial resources, marine resources have not been fully explored for synthesis of noble metal NPs. Our present review is designed to speculate the importance of usage of vast marine resources and its mediated NPs synthesis, in particular seaweed-mediated NPs synthesis to overcome the limitations involved in physical and chemical methods. Finally, recent advancements in greener synthesis of metal NPs, their size, distribution, morphology and applications such as antimicrobial, antifouling and anticancer potentials are briefly described along with portraying the prospective scope of research in this field without any negative impact on the environment.

A novel actinobacterium, Streptomyces rochei (MSA-14) was isolated from the mining sediments of Indian Rare Earth (IRE) Ltd. southwest coast of India. Secondary metabolites were extracted from S. rochei using ethyl acetate. The crude ethyl acetate extract exhibited prominent antibacterial property with wide spectral inhibitory zones (3–15 mm) having least Minimum Inhibitory Concentration (1–50 μg/ml) and Minimum Bactericidal Concentration (10–100 μg/ml) against the tested bacterial pathogens. The extract evidenced remarkable antioxidant (91%) and hemolytic (45.52%) properties at 800 μg/ml. In addition, the extract recorded good cytotoxic effect against Artemia salina nauplii with the LC50 value of 106.75 μg/ml. Further, the extract was purified by normal phase silica column chromatography using step gradient solvent method. Among the column fractions, 14th fraction rendered good biomedicinal properties. The bioassay guided 14th fraction was further purified by preparative TLC. The lead compound was analysed using FT-IR and GC-MS analysis, which ascribed a prominent bioactive compound Pyrrolidine-2,4-Dione. In silico analysis on the biodegradability of Pyrrolidine-2,4-Dione using BIOWIN and ECOSAR signified that the identified bioactive compound is more plausible for the environment, eco-friendly, easily degradable within days to week under aerobic and anaerobic conditions. Also, it is non-toxic against chosen bacterial pathogens when compared with the standard antibiotic Streptomycin.

The present study was undertaken to bring out a cost effective feed from fish silage for promoting growth in common carp, Cyprinus carpio. For this, acid silages were prepared using fishery wastes supplemented with three different concentrations (2, 2.5 and 3%) of formic acid and fermented for 30 days. During fermentation, the physicochemical parameters and aerobic plate count of silage products were estimated for 30 days at an interval of 10 days. Results indicated that pH, dry matter, ash, protein contents and aerobic plate count showed a declining trend during ensilaging day's interval. However, lipid and mineral contents were gradually increased up to 30th day. After 30 days of fermentation, the amino acids and vitamins were quantitatively as well as qualitatively ascertained in all silages. Further, the individual silage products were used as one of the major ingredients to prepare formulated diets (E1: 2%; E2: 2.5% and E3: 3%). The prepared diets were fed to C. carpio fingerlings for 45 days and the growth promoting efficacy of the diets was tested. From the results it was understood that, 2% acid silage diet had higher weight gain (2.38g), SGR (1.49%) and significant increase in biochemical constituents than other diets fed fish