Partial characterisation of a colored organic metabolite isolated from cultures of Acidithiobacillus ferrooxidans grown on elemental sulfur

摘要

The aim of the study was the physico-chemical characterisation of a violet-colored metabolite isolated from a culture ofAcidithiobacillus ferrooxidans grown on elemental sulfur. The metabolite, which was bound to the surface of the bacterial cells, was detectable visually after prolonged culture incubation, corresponding to a pH change from about pH 4 to about pH 0.5. When extracted from the bacteria, the metabolite was found to be hydrophobic and insoluble in water. X-ray structure analysis, mass spectroscopy, and NMR were used to elucidate the chemical structure of this metabolite. The results of all these methods were consistent, and confirmed the existence of aromatic pyrene rings which were connected, probably via aliphatic chains, to cell exopolymers. The amount of the metabolite produced varied from culture to culture, though the conditions which promote its production are currently unknown. The proposed chemical structure of the colored metabolite indicated a possible role in the adsorption of At. ferrooxidans cells onto particulate elemental sulfur.