| biomineralization of gold: biofilms on bacterioform gold. | bacterial biofilms are associated with secondary gold grains from two sites in australia. 16s ribosomal dna clones of the genus ralstonia that bear 99% similarity to the bacterium ralstonia metallidurans-shown to precipitate gold from aqueous gold(iii) tetrachloride-were present on all dna-positive gold grains but were not detected in the surrounding soils. these results provide evidence for the bacterial contribution to the authigenic formation of secondary bacterioform gold grains and nuggets. | 2006 | 16840703 |