Fermentative degradation of triethanolamine by a homoacetogenic bacterium.
With triethanolamine as sole source of energy and organic carbon, a strictly anaerobic, gram-positive, rod-shaped bacterium, strain LuTria 3, was isolated from sewage sludge and was assigned to the genus Acetobacterium on the basis of morphological and physiological properties. The G+C content of the DNA was 34.9 +/- 1.0 mol %. The new isolate fermented triethanolamine to acetate and ammonia. In cell-free extracts, a triethanolamine-degrading enzyme activity was detected that formed acetaldehyde as reaction product. Triethanolamine cleavage was stimulated 30-fold by added adenosylcobalamin (co-enzyme B12) and inhibited by cyanocobalamin or hydroxocobalamin. Ethanolamine ammonia lyase, acetaldehyde:acceptor oxidoreductase, phosphate acetyltransferase, acetate kinase, and carbon monoxide dehydrogenase were measured in cell-free extracts of this strain. Our results establish that triethanolamine is degraded by a corrinoid-dependent shifting of the terminal hydroxyl group to the subterminal carbon atom, analogous to a diol dehydratase reaction, to form an unstable intermediate that releases acetaldehyde. No anaerobic degradation of triethylamine was observed in similar enrichment assays.
Frings
J
J
Fakultät für Biologie, Universität Konstanz, Germany.
Wondrak
C
C
Schink
B
B
D001673:Biodegradation, Environmental; D004983:Ethanolamines / Q000378:metabolism*; D005285:Fermentation; D016987:Gram-Positive Rods / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*
D004983:Ethanolamines; C009546:triethanolamine