Microbial synthesis of CuNPs using Brevundimonas diminuta strain and its antibacterial activity

Mahesh H Joshi, Ashwini A Patil, Smita Chaudhary and Ravindra D Kale

Abstract

Green synthesis of nanoparticles is an emerging nanoparticle synthesis method due to its simplicity and non-toxicity. In the present study, we report the ability of Brevundimonas diminuta strains obtained from mining soil to synthesize copper nanoparticles (CuNPs). These strains were isolated from mining soil, identified and characterised. A bacterial enzyme, which is a characteristic for this species, was isolated, centrifuged and the resultant supernatant solution was used for nanoparticle synthesis from CuCl₂. UV-visible spectrophotometer was used to assess the formation of nanoparticles. The size of the nanoparticles was verified using X-ray powder diffraction (XRD) and nanoparticle size analyser. Fourier-transform infrared spectroscopy (FTIR) was used to characterise the chemical nature of the reducing and capping agents present on the nanoparticles. Additionally, the effect of pH, time and concentration of CuCl₂ on the CuNPs formation was also investigated. The synthesised nanoparticles showed anti-bacterial activity. The favourable synthesis of stabilised CuNPs demonstrates the relevancy of the isolated Brevundimonas diminuta strain for its bulk synthesis.