Prospects of Actinomycetes as Bio-factories for Green Synthesis of Metal Nanoparticles: Evaluating Potential and Challenges

Nanotechnology has significantly impacted various sectors, such as medicine, agriculture, and industry, owing to the unique properties of nanoparticles (NPs). NPs are synthesized utilizing chemical, physical, and biological methods. The green synthesis of NPs can be mediated by plants, fungi, bacteria, and viruses. The green synthesis of NPs offers advantages such as environmental sustainability, biocompatibility, and reduced toxicity compared to chemical and physical methods. This review focuses on bacteria-mediated biosynthesis of NPs, particularly actinomycetes- Gram-positive filamentous bacteria known for their role in producing bioactive secondary metabolites, especially antimicrobial compounds. Actinomycetes employ various pathways and biomolecules, including NADH-dependent and non-NADH-dependent enzymes, exopolysaccharides, proteins, oligopeptides, and pigments, to reduce metal ions to NPs in extracellular and cell-dependent situations. We also discuss the potential for large-scale production, the challenges involved, and the prospects of actinomycetes in the biosynthesis of NPs. The diverse applications of metallic NPs in antimicrobial treatments, environmental remediation, and nanomedicine demonstrate the significance of further research in this field. Finally, a review of this article shows that actinomycetes have the potential to participate in the green synthesis of metallic NPs.