New isolation of Clostridium aceticum (Wieringa).

After many attempts to re-isolate Clostridium aceticum (Wieringa) had been unsuccessful, finally a new strain could be isolated that was morphologically and physiologically identical, as could be demonstrated by comparing this strain with the original one, retrieved recently from an old culture collection. Both strains showed the ability to produce cellular materials and acetate from a CO2-H2 gas mixture, as well as from fructose as the substrate. A detailed description of the enrichment and isolation procedures used, is given.