Fig. 3

Diagram illustrating the processes involved in the extracellular and intracellular production of metal NPs. metal NPs are produced extracellularly by ensnaring metal ions on the cell wall and reducing them in the presence of metabolites or released enzymes. Following the passage of metal ions into the cytoplasm of the cell, the metal ions are reduced during the intracellular production of metal NPs due to metabolic interactions with enzymes such as nitrate reductase [65]