Biosynthesis of silver nanoparticles from marine diatoms Chaetoceros sp., Skeletonema sp., Thalassiosira sp., and their antibacterial study

[Display omitted] •Marine Diatoms have been envisaged for AgNP synthesis.•The average size of AgNP ranges from 150 to 350 nm.•Diatom based AgNP exhibits excellent biocidal activity.•These AgNP showed inhibition against both Gram-positive and Gram negative bacteria. Diatoms are a reservoir of metabolites with diverse applications and silver nanoparticle (AgNP) from diatoms holds immense therapeutic potentials against pathogenic microbes owing to their silica frustules. In the present study, Chaetoceros sp., Skeletonema sp., and Thalassiosira sp were used for synthesis of AgNP. The average particle size of AgNP synthesized was 149.03 ± 3.0 nm, 186.73 ± 4.9 nm, and 239.46 ± 44.3 nm as reported in DLS whereas 148.3 ± 46.8 nm, 238.0 ± 60.9 nm, and 359.8 ± 92.33 nm in SEM respectively. EDX analysis strongly indicates the confirmation of AgNP displaying a sharp peak of Ag+ ions within the spectra. High negative zeta potential values indicate a substantial degree of stabilization even after three months. The antibacterial efficacy of biosynthesized AgNP tested against Aeromonas sp., Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Streptococcus pneumonia exhibits broad-spectrum antibacterial activity. This study encourages the synthesis of diatom based AgNP for a variety of applications owing least toxicity and biodegradable nature.