Green synthesis, characterization and applications of iron and zinc nanoparticles by probiotics.

The synthesis of nanoparticles (NPs) by microorganisms is one of the most promising areas of research in modern nanotechnology since microorganisms can easily act as real nanofactories of industrially relevant compounds. Recent studies suggest that probiotic bacteria have an intrinsic potential to synthesize metal NPs when grown in the presence of metal ions. In such conditions, they can reduce metal ions through different biochemical mechanisms occurring both intra and extracellularly, and leading to the production of NPs. Different approaches have proposed the synthesis of silver, gold, titanium or selenium NPs from probiotics, with promising health related effects. However, their use for the production of iron and zinc NPs has been scarcely reported. Considering the nutritional relevance of iron and zinc, a thorough approach about the synthesis of iron and zinc NPs by probiotics was addressed, including the factors affecting the synthesis processes, the mechanisms of synthesis, and the physical and chemical characterization of NPs. The impact of products containing probiotics and minerals has applications in many different fields going beyond the food industry and representing a powerful strategy as economic engine for very diverse industries and countries.