Biogenic Silver Nanoparticles Synthesis from New Record Aquatic Bacteria of Nile Tilapia and Evaluation of their Biological Activity

The current study investigates the isolation identification of bioactive strain from fish collected from El-Burrllus region in Egypt. The objective of the current study is to identify and assess the biological profile of a new record strain in Egypt Bacillus maritimus. The molecular identification of the selected promising isolate and phylogenetic analysis confirmed the accurate identity of the isolate as Bacillus maritimus. The novelty of the present study was not due to only to the fact that the Bacillus maritimus isolate was the first record from brackish-water Egyptian fish gut, but also due to the fact that there is no previous study on the bioactivity of Bacillus maritimus and their efficiency as biogenic nanoparticles synthesis. The bioactivities for the Bacillus maritimus were investigated through different biochemical assays as antioxidant, anti-inflammatory and antimicrobial activity against six of the tested human pathogens namely; Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 8739, Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 15442, Klebsiella pneumoniae ATCC 13883 and Streptococcus pyogenes ATCC 19615. Bacillus maritimus bacteria were grown in nutrient broth for 24 h at 37°C and the optical density was determined at 600 nm using the UV-visible spectrophotometer. The optical density (OD) of the broth was adjusted to 0.5 with sterile phosphate-buffered saline, pH 7.4 (PBS). the bacterial isolate showed antioxidant, and anti-inflammatory activities. In addition the bacteria showed great reducing agent ability as a biogenic agent for the silver nanoparticles. The phytochemical screening of the Bacillus maritimus isolates have showed varieties of bioactive groups in addition to total phenolic compounds, flavonoids, tannic acid, carbohydrates, sulfated polysaccharides, total proteins and lipids. This study highlighted also that the Bacillus maritimus isolate could also produce novel secondary metabolites. The current study report for the first time the Bacillus maritimus in Egypt. Further studies are needed to isolate and characterize more bioactive strains from Egyptian Fishes that could possibly act as novel bioactive compounds source of medical and agricultures importance.