Microbial-enabled green biosynthesis of nanomaterials: Current status and future prospects

Global challenges require novel solutions. Microbial nanotechnology has the potential to offer an eco-friendly approach for advancing the pharmaceutical, food, environment and agriculture sectors. This review summarizes recent developments in the synthesis and applications of bionanomaterials created by intracellular and/or extracellular biosynthesis processes involving various microorganisms (e.g. bacterium, fungus, yeast, virus and microalga) and/or derived metabolites/secreted substances. Insights into the mechanisms underlying the synthesis of microbial-assisted nanomaterials, and the superiority of these 'green' processes and resulting microbiotic nanomaterials in various applications, are provided. Such knowledge supports the development of microfactories for the biosynthesis of diverse nanomaterials at scale under controlled conditions. This review highlights current hurdles and bottleneck issues, whilst demonstrating the need to manipulate microorganisms at both the genomic and proteomic levels, thereby tailoring the properties of the derived bionanomaterials for target applications. For many envisaged applications, toxicological and ecotoxicological studies on synthesized nanomaterials are needed, along with the establishment of suitable regulatory frameworks.