Biofilm disruption activity of silver nanoparticles synthesized by Acinetobacter calcoaceticus PUCM 1005

• First report on protein mediated AgNP synthesis employing Acinetobacter calcoaceticus.
• Only 48 h old culture produced extracellular AgNP.
• Optimization of physiological parameters increased AgNP synthesis.
• AgNPs inhibited Gram negative bacteria more efficiently than Gram positive.
• AgNPs could disrupt 24 h biofilm of Gram negative and Gram positive bacteria.

Biosynthesis of silver nanoparticles (AgNPs) using Acinetobacter calcoaceticus PUCM 1005 and their application in biofilm disruption is described. Extracellular AgNPs were produced by 48 h grown culture when challenged with silver nitrate. AgNPs synthesis was found to be optimum at 40 mM AgNO3, 40 °C temperature and pH 5. UV–vis spectroscopy, energy dispersive spectra and X-ray diffraction analysis confirmed presence of AgNPs. Electron microscopy revealed the size range to be 4–40 nm. These AgNPs exhibited higher activity against planktonic Gram negative pathogens. However, they could disrupt biofilm formed by Gram negative and Gram positive pathogenic microorganisms. AgNP synthesis was protein mediated.