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Desulfuromonas acetoxidans, which is regarded to the oldest microorganisms that exist in the Earth, are uncoloured
gram-negative obligatory anaerobic bacteria that have an ability to reduce S0 to H2S. This process supports bacteria with
sufficient amount of energy which they need for growth. At the same time high concentrations of hydrogen sulfide are
very toxic towards all living organisms. Different metal ions that exist in surrounding environment in small
concentrations are essential for microorganisms because they support normal functionality of them. But in high
concentrations they have a detrimental influence on cell structure and it functions. Srains of D. acetoxidans bacteria that
have high toxic metals resistance can neutralize the toxicity of hydrogen sulfide, which is the final product of
dissimilative sulfurreduction, and these metals as the result of their particular binding and forming the insoluble
precipitations. Light scattering changes and metals accumulation ability of D. acetoxidans bacterial cells under the
influence of CuSO4, PbNO3, ZnSO4 and CdSO4 have been investigated. The changes of light scattering characteristics of
bacterial D. acetoxidans cells on the base of their size distribution and relative content under the influence of
investigated metal salts have been observed by the new method of measurement.
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