Microbial transformations of inorganic sulphur compounds in soil under conditions of heterocontinuous cultivation.

Development and activity of the association of the sulphur cycle bacteria, represented by Thiobacillus thioparus and Desulfovibrio sp., were followed in chernozem soil continuously supplemented with sodium thiosulphate. The technique of heterocontinuous cultivation made it possible (i) to determine changes in the individual components of microflora involved in successive metabolic steps, their time and space sequence, (ii) to follow changes in the transformations of substrate and formation of metabolic products, and (iii) to reach a steady state in the system. A possible use of this approach for the evaluation of the effect of ecological factors, for modelling microbiological processes of the sulphur cycle, for the investigation of trophic relationships among microorganisms in natural and artificial association and for the evaluation of the geochemical activity of sulphur bacteria is discussed.