Sulphur isotope fractionation by Desulfovibrio and Desulfotomaculum species

Isotopic analysis of H₂S evolved during the growth of Desulfovibrio species and Desulfotomaculum species on a defined sulphate medium at their specific optimal growth temperature indicate no noticeable intrageneric or intergeneric differences in regard to isotopic fractionation. Changes in the composition of the growth medium were reflected in minor changes in the isotopic composition of the H₂S evolved and in the rate of sulphate reduction. Intergeneric differences were noted in resting cell experiments and in the organisms' ability to reduce sulphite.