Coalescence of Nanoclusters and Formation of Submicron Crystallites Assisted by<i>Lactobacillus</i>Strains

TLDR

Lactobacillus strains, common in buttermilk, facilitate the growth of submicron gold, silver, and gold‑silver alloy crystals when exposed to precursor ions. Crystal growth occurs by coalescence of nanoclusters within and around the bacteria, producing well‑defined submicron morphologies that do not affect bacterial viability, can be harvested intact, and point to applications in analytical chemistry, nanotechnology, medicine, and metal‑ion recovery.

Abstract

Lactobacillus strains, common in buttermilk, assist the growth of gold, silver, and gold−silver alloy crystals of submicron dimensions upon exposure to the precursor ions. Several well-defined crystal morphologies are observed. Crystal growth occurs by the coalescence of clusters, and tens of crystals are found within the bacterial contour. Crystal growth does not affect the viability of the bacteria. Crystals are presumably nucleated through nanoclusters, which are formed within as well as transported into the bacteria. Biomass with the crystals can be harvested completely. Results point to potential applications in analytical chemistry, nanotechnology, medicine, and metal ion recovery. Coalescence appears to be a route by which surface area of the crystal is reduced so that it can be effectively protected to avoid biological damage.