Microbial cell factories a new dimension in bio-nanotechnology: exploring the robustness of nature

Bio-based nanotechnology has its existence in biological dimensions e.g. microbial cell factories (bacteria, fungi. algae, yeast, cyanobacteria) plants, and biopolymers. They provide multipurpose biological platforms to supply well-designed materials for diverse nano-biotechnological applications. The "green or bio-based synthesis of nanoparticles (NPs)" has witnessed a research outburst in the past decade. The bio-based synthesis of NPs using microbial cell factories is a benign process and requires mild conditions for the synthesis with end products being less/non-toxic. As a result, its application has extended in multitudinous industries including environment, cosmetics, and pharmaceutical. Thus, the present review summarizes all the significant aspects of nanotechnology and the reason to switch towards the bio-based synthesis of NPs using microbial cell factories. It consists of a detailed description of the bio-based methods employed for the synthesis and classification of NPs. Also, a comprehensive study on the application of bio-based NPs in the various industrial and biotechnological domains has been discussed. The limitation and its solution would help identify the applicability of NPs to "identified and unidentified" sectors.