摘要：

Two sulfate reducing bacteria (Madison and Marburg strains) that grew on H 2 plus sulfate in a mineral salts medium that contained acetate and CO 2 as sole carbon source were isolated from diverse environments. During growth in this medium 4.2 mol of H 2 were consumed per mol of sulfate reduced to sulfide. Acetate was required for biosynthetic purposes only. Approximately 70% of the cell carbon synthesized was derived from acetate and 30% from CO 2 . Acetate was not involved in dissimilatory sulfate reduction.Growth of the bacteria on H 2 plus sulfate was linear rather than exponential, and a doubling time at the beginning of linear growth of approximately 3 h was observed. The optimal growth temperature was found to be near 35° C. Cultures could be grown up to a density of 500 mg cells (dry weight) per liter. Growth yield studies demonstrated that between 4 and 5 g of cells (dry weight) were formed per mol of sulfate reduced to sulfide.The chemolithotrophically growing sulfate reducing isolates were identified as Desulfovibrio species by being obligately anaerobic, gram negative, non spore forming vibrios that contained desulfoviridin and cytochrome c 3 (350–450 nmol/g protein). The organisms were found to be monopolarly and monotrichously flagellated. The abilities of the two strains to grow on electron donors other than H 2 and to use electron acceptors other than sulfate differed considerably. The DNA base composition of the Madison and Marburg strains were 60 and 63.5 mol % GC, respectively. The taxonomic status of the strains was discussed.

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