Energy conservation in fermentative glutarate degradation by the bacterial strain WoG13

Abstract

Dicarboxylic acids with 2-5 carbon atoms can be degraded fermentatively by pure cultures of various strictly anaerobic bacteria. The small amount of free energy released in these decarboxylations (about 20-25 kJ mol-1) is conserved as sole source of growth energy either through sodium-pumping decarboxylases or through electrogenic substrate/product transport devices. In the glutarate-fermenting bacterial strain WoG13 a glutaconyl-CoA-decarboxylating enzyme activity was detected. This enzyme was inhibited by avidin and was stimulated by sodium ions. The enzyme activity was partially associated with the cytoplasmic membrane, indicating that energy conservation is accomplished through a sodium-ion-pumping glutaconyl-CoA decarboxylase enzyme.