ROLE OF MICROORGANISMS IN VANADIUM CONCENTRATION AND DISPERSION

Qualitative and quantitative aspects of the reduction of pentavalent vanadium to lower oxidation states under anaerobic conditions by two newly isolated strains of Pseudomonas were studied. Vanadate was reduced to tetra- and trivalent states by growing cultures with organic electron donors as well as with molecular hydrogen and carbon monoxide. The temperature optimum for anaerobic growth and vanadate reduction was between 28 and 30-degrees-C and the pH optimum was between 7 and 8. The findings confirm that both microorganisms are facultatively anaerobic and facultatively chemolithotrophic. A mineral similar to sherwoodite was detected in cultures of the vanadate-reducing bacteria. This suggests that microorganisms may be involved in epigenetic vanadium mineral formation. Microorganisms belonging to various taxons including Pseudomonas were found to be highly resistant to vanadium. Various microorganisms were also found to accumulate vanadium.