Clostridium aceticum (Wieringa), a microorganism producing acetic acid from molecular hydrogen and carbon dioxide

Spores of Clostridium aceticum (Wieringa) from 1947 have been revived, and a study for a redescription of this microorganism has been carried out. C. aceticum was Gram negative. The cells were rodshaped and peritrichously flagellated. Round spores were formed in terminal position. The DNA contained 33 mol % guanine plus cytosine. The organism was obligately anaerobic and grew either chemolithotrophically with H2 + CO2 or chemoorganotrophically with compounds such as fructose, L-glutamate, L-malate or pyruvate. H2 and CO2 were converted to acetic acid according to the following equation: 2CO2 + 4H2 leads to CH3COOH + 2H2O The optimal temperature for growth was 30 degrees C. The optimal pH for chemolithotrophic growth was 8.3. The doubling times for chemolithotrophic and chemoorganotrophic growth were 25 and 8 h, respectively.