Green Synthesis of Metal nanoparticles by microorganisms; a current prospective

Synthesis and applications of nanomaterials has been an interesting area of nanotechnology since last decade. Several physico-chemical methods have been used to synthesize the nanoparticles of noble metals. Numerous other methodologies are also in practice including the laser ablation, aerosol technologies, lithography, and ultraviolet irradiation.  However, traditional methods are less preferred because they remain costly and involve the use of hazardous chemicals.  Biological routes of synthesizing metal nanoparticles via microbes is gaining much attention due to their low toxicity, biocompatibility and eco-friendly nature.  The development of reliable, eco-friendly, sustainable processes for the synthesis of nanoparticles with precise shapes, sizes and dispersity is a progressive area of nano-biotechnology. Despite the higher stability of biogenic nanoparticles there is still need to optimize the synthesis rate and other factors affecting the synthesis process. Microbial synthesis of silver, gold, platinum, titania, zirconia, magnetite nanoparticles and quantum dots has been described successfully. However molecular mechanisms that mediates the synthesis of nanoparticles should be elucidated further to improve the properties of nanoscale materials and production rate. Due to the rich biodiversity of microbes, their potential as a useful source for the production of nanoparticle is yet to be fully explored. The present review emphases the current status of potential microbial sources for the synthesis of metal nanoparticles.