Sustainable and Ecofriendly Nanoparticle Synthesis Using Microbial Strains Isolated From Heavy Metal Rich Industrial Effluent

ABSTRACT Given the enormous potential of metal nanomaterials, their sustainable production is of paramount importance and is a key area of focus worldwide. In this regard, bacteria are highly valued because of their potential for rapid, cost-effective and eco-friendly metal nanomaterial synthesis. In this study, culture supernatants of Bacillus cereus and Curvularia sp isolated from heavy metal rich Titanium industry effluent effectively synthesised cobalt and copper nanoparticles of narrow size range at room temperature, neutral pH and static conditions within 2-7 days. This was verified by visible colour changes, UV-Vis spectroscopy and FT-IR. The UV-Visible spectra of the biosynthesized cobalt and copper nanoparticles exhibited sharp narrow peaks at 341 and 342 nm. This suggested that the cobalt and copper nanoparticles were not only small but also had a narrow size distribution, a feature rarely reported in biosynthesis studies. Furthermore, our approach was conducted at room temperature using cell-free supernatant, eliminating the need for additional heating or cooling, and minimising processing thus making the process energy-efficient, cost effective and sustainable. This is a first report on the production of monodisperse cobalt and copper nanoparticles by microbes isolated from this novel extreme environment. Graphical abstract