ANAEROBIC DEGRADATION OF LONG-CHAIN DICARBOXYLIC-ACIDS BY METHANOGENIC ENRICHMENT CULTURES

Methanogenic enrichment cultures fermented the long-chain dicarboxylat es adipate, pimelate, suberate, azelate, and sebacate (C6-C-10) Stoich iometrically to acetate and methane. After several transfers, the cult ures contained cells of only a few morphologically distinguishable typ es. During anaerobic degradation of dicarboxylic acids with even-numbe red carbon atoms, propionate accumulated intermediately, and butyrate was the intermediate product of degradation of those with an odd numbe r of carbon atoms. Degradation of the long-chain dicarboxylates depend ed strictly on the presence of hydrogenotrophic methanogens. The prima ry attack in these processes was beta-oxidation rather than decarboxyl ation. A general scheme of anaerobic degradation of long-chain dicarbo xylic acids has been deduced from these results.