Biogenic formation of photoactive arsenic-sulfide nanotubes by Shewanella sp strain HN-41

Abstract

Microorganisms facilitate the formation of a wide range of minerals that have unique physical and chemical properties as well as morphologies that are not produced by abiotic processes. Here, we report the production of an extensive extracellular network of filamentous, arsenic-sulfide (As-S) nanotubes (20-100 nm in diameter by approximate to 30 mu m in length) by the dissimilatory metal-reducing bacterium Shewanella sp. HN-41. The As-S nanotubes, formed via the reduction of As(V) and S2O32-, were initially amorphous As2S3 but evolved with increasing incubation time toward polycrystalline phases of the chalcogenide minerals realgar (ASS) and duranusite (As4S). Upon maturation, the As-S nanotubes behaved as metals and semiconductors in terms of their electrical and photoconductive proper-ties, respectively. The As-S nanotubes produced by Shewanella may provide useful materials for novel nano- and opto-electronic devices.