THE REGULARITIES OF IRON COMPOUNDS TRANSFORMATION BY CITROBACTER FREUNDII MI-31.1/1

The purpose ofthe work was to study the regularities ofFe(III) compounds reduction under the conditions of limited aeration by the strain Citrobacterfreundii Ml-31.1/1, and to assess the role ofFe(II)-reducing bacteria (FRB) in iron compounds transformation in ecosystems. The following methods were used: cultivation of microorganisms under the conditions of limited aeration, colorimetric determination ofbiomass and Fe(III) and Fe(I) compounds concentra- tion, the potentiometric measuring ofpH and Eh, gas chromatography. Results: Thermody- namic calculations of microbial interaction with iron compounds were experimentally verified The regularities of Fe(III) and Fe(I) compounds transformation by the model strain Citro- bacterfreundii Ml-31.1/1, isolatedfrom the typical mid-latitude ecosystem -river sludge were obtained. The balance ofiron compounds redistribution in cells and in the extracellularfraction was established Conclusions: The results obtained are the basis to assume that non-specific interaction of microorganisms with iron may significantly influence transformation of iron. Thermodynamic prognosis allows to carry out targeted regulation of microbial metabolism.