title: Less is more, greener microbial synthesis of silver nanoparticles.
abstract: Microbial nano-synthesis has been well established as a green method for the sustainable development of nanotechnology. However, the mechanism of this biotechnology has to be reconsidered with the increasing realization that microorganism culture broth plays a vital role during the synthesis, which may obviate the dependence on microbes. Here, we demonstrate that silver nanoparticles (AgNPs) could be synthesized in several types of microorganism culture broth (an aqueous solution abundant in peptone, yeast extract from Saccharomyces cerevisiae, dextrose and other reducing and stabilizing agents) without any specific living microbe involvement. Light and high pH values of broth were identified as two critical factors in ensuring pure AgNPs formation. In broths containing NaCl at high concentration (0.5wt%), silver chloride was identified as the major intermediate and could be converted to AgNPs via one-pot photoreduction. Our broth alone strategy dramatically simplifies the conventional microbial nano-synthesis process by cutting the use of microorganisms and thus provides a more eco-friendly way for nano-Ag preparation. The fundamental understanding of the microbial synthesis mechanisms and implementing of complete green methods to fabricate technologically important nanomaterials will be further promoted by this study.
authors.affiliation: Department of Chemical Engineering, Curtin University, Bentley 6845, Western Australia, Australia.
authors.forename: Lihong
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Chemical Engineering, Curtin University, Bentley 6845, Western Australia, Australia.
authors.forename: Tingting
authors.initials: T
authors.lastname: Liu
authors.affiliation: Department of Chemical Engineering, Curtin University, Bentley 6845, Western Australia, Australia.
authors.forename: Moses
authors.initials: M
authors.lastname: Tade
authors.affiliation: Department of Chemical Engineering, Curtin University, Bentley 6845, Western Australia, Australia.
authors.forename: Shaobin
authors.initials: S
authors.lastname: Wang
authors.affiliation: School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
authors.forename: Xinyong
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Chemical Engineering, Curtin University, Bentley 6845, Western Australia, Australia. Electronic address: Shaomin.Liu@curtin.edu.au.
authors.forename: Shaomin
authors.initials: S
authors.lastname: Liu
mesh_terms: D001412:Bacillus subtilis / Q000378:metabolism; D003470:Culture Media / Q000737:chemistry; D004926:Escherichia coli / Q000378:metabolism / Q000648:ultrastructure; D055772:Green Chemistry Technology; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology; D055668:Photochemical Processes; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D012834:Silver / Q000378:metabolism*
chemical_list: D003470:Culture Media; D012834:Silver
keywords: Ag nanoparticles; Microbial culture broth; Microbial green synthesis; Yeast extract