Abstract
Acetobacterium woodii, Acetohalobium arabaticum, Clostridium formicoaceticum, and Sporomusa silvacetica were found to contain carbonic anhydrase (CA). Minimal to no CA activity was detected in Moorella thermoautotrophica, Moorella thermoacetica subsp. "pratumsolum," Sporomusa termitida, and Thermoanaerobacter kivui. Of the acetogens tested, A. woodii had the highest CA specific activity, approximately 14 U mg of protein(-1), in extracts of either glucose- or H2-CO2-cultivated cells. CA of A. woodii was cytoplasmic and was purified approximately 300-fold to a specific activity of 5,236 U mg of protein(-1). Intracellular acetate concentrations inhibited CA activity of A. woodii by 50 to 85%, indicating that intracellular acetate may affect in situ CA activity.