Isolation And Identification Of Bioactive Secondary Metabolites From The Marine Bacteria Shewanella Algae And Their Biological Activity
Year: 2026
Type: article
Abstract: Background: Marine bacteria are a prolific source of bioactive secondary metabolites with significant pharmaceutical potential, particularly in addressing antibiotic resistance and chronic diseases. Aim: This study aimed to isolate and identify bioactive secondary metabolites from the marine bacterium Shewanella algae, and to evaluate their antioxidant activity. Methodology: Marine sediment samples were collected from the coastal region of Ramanathapuram (latitude: 9.319078°, longitude: 79.330245°). Bacterial isolates were obtained via serial dilution. Pure colonies were isolated using the streak plate method. Phenotypic identification involved Gram staining and a series of biochemical tests, while genotypic identification was performed by 16S rRNA gene sequencing and phylogenetic analysis. Bioactive compounds were extracted from the biomass using ethyl acetate. Purification through medium-pressure liquid chromatography (MPLC) and thin-layer chromatography (TLC). Structural characterization was conducted using FT-IR, NMR, and LC-MS. Antioxidant activity was assessed using the DPPH assay, with results compared to ascorbic acid. Results: Shewanella algae was successfully isolated and identified, exhibiting a distinct metabolic profile (citrate and glucose positive; indole, methyl red, and several sugars negative). The primary purified compound was identified as 9-isopropyl-3,6-dimethoxy-9-methyl-9Hfluorene, with a purity of 90.55% (RT: 1.12 min, LC-MS m/z: 283.4 [M+1]). The ethanolic extract demonstrated notable antioxidant activity with an IC50 of 8.82 μg/mL (R² = 0.8512), compared to ascorbic acid (IC50 = 0.8 μg/mL, R² = 0.8963). Conclusion: Shewanella algae from marine sediments produce a novel fluorene derivative with significant antioxidant activity. These findings highlight the potential of marine bacteria as a source of new bioactive compounds for pharmaceutical development.
Institutions: Annamalai University, Sri Krishnadevaraya University
Language: English
Subfield: Applied Microbiology and Biotechnology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W7154111431