Rapid Biosynthesis of gold nanoparticles by the extracellular secretion of bacillus niabensis 45: Characterization and antibiofilm activity

Abstract

The present study demonstrated that the extracellular biosynthesis of gold nanoparticles (GNPs) using B. niabensis 45 may be mediated by a cyclic peptide (P2). The molecular weight of P2 was determined to be about 1122 Da by MALDI-TOF-MS and ESI-MS. A novel protocol for rapid biosynthesis of GNPs using P2 was developed. The results showed that GNP synthesis could be completed in a wide range of temperatures (40-100°C) and pH (6.0-10.0) within few minutes when 9 mL of P2 (2 mg/mL) and 1 mL of HAuCl4 solution (2 mM) were mixed together. The synthesized GNPs were further characterized. Energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analysis confirmed the presence of elemental gold and crystalline structure of the GNPs, respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed the formation of spherical metallic GNPs. The size distribution of GNPs calculated using ImageJ software was found to be 10-20 nm. And these GNPs showed excellent antibiofilm activity against Pseudomonas aeruginosa PAO1 and Staphylococcus aureus ATCC25923. The results revealed microbial cyclic peptides could be used as synthesis of GNPs which had potent antibiofilm potential.