SPECTROSCOPIC CHARACTERIZATION OF MINERAL CRYSTALS PRODUCED BY THE BACTERIUM AZOSPIRILLUM-BRASILENSE

The results of spectroscopic structural and trace elemental analyses o f mineral crystals produced by the soil nitrogen-fixing bacterium Azos pirillum brasilense cultivated in a synthetic medium are presented and discussed. The mineral formed is shown to have a structure close to s truvite (MgNH4PO4 x 6H(2)O; ASTM file No. 15-762) with some difference s which may be attributed to the presence of isomorphic admixtures of other cations (struvite is known to have a variety of forms). AAS/AES and ion chromatography analyses for a number of biologically important microelements and their role in the formation of the crystal structur e, as well as some questions related to biomineralization are,also dis cussed.