Figure 2.

Mechanistic representation of the synthesis of nanoparticle by microbes. Formation of nanoparticles by microbes involves metal capture, enzymatic reduction, and capping. Metal ions are first trapped on the surface or inside of the microbial cells and then reduced to nanoparticles in the presence of enzymes. The enzyme serves as the nucleation site, providing electrons to the metal for its reduction. Microorganisms can impact mineral formation through the production of organic polymers, which can impact nucleation by favoring (or inhibiting) the stabilization of the very first mineral seeds.