Mechanism of anaerobic degradation of triethanolamine by a homoacetogenic bacterium.
Triethanolamine (TEA) is converted into acetate and ammonia by a strictly anaerobic, gram-positive Acetobacterium strain LuTria3. Fermentation experiments with resting cell suspensions and specifically deuterated substrates indicate that in the acetate molecule the carboxylate and the methyl groups correspond to the alcoholic function and to its adjacent methylene group, respectively, of the 2-hydroxyethyl unit of TEA. A 1,2 shift of a hydrogen (deuterium) atom from -CH2-O- to =N-CH2- without exchange with the medium was observed. This fact gives evidence that a radical mechanism occurs involving the enzyme and/or coenzyme molecule as a hydrogen carrier. Such a biodegradation appears analogous to the conversion of 2-phenoxyethanol into acetate mediated by another strain of the anaerobic homoacetogenic bacterium Acetobacterium.
Speranza
Giovanna
G
Dipartimento di Chimica Organica e Industriale, Università degli Studi di Milano, via Venezian 21, I-20133 Milano, Italy. giovanna.speranza@unimi.it
Morelli
Carlo F
CF
Cairoli
Paola
P
Müller
Britta
B
Schink
Bernhard
B
D000079:Acetaldehyde / Q000737:chemistry; D000085:Acetates / Q000737:chemistry; D045855:Acetobacterium / Q000378:metabolism* / Q000502:physiology; D000641:Ammonia / Q000737:chemistry; D001669:Biochemical Phenomena; D001671:Biochemistry; D001673:Biodegradation, Environmental; D003903:Deuterium / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D004983:Ethanolamines / Q000737:chemistry*; D005026:Ethylene Glycols / Q000737:chemistry; D005609:Free Radicals; D006859:Hydrogen / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical
D000085:Acetates; D004983:Ethanolamines; D005026:Ethylene Glycols; D005609:Free Radicals; D000431:Ethanol; D000641:Ammonia; D006859:Hydrogen; C009546:triethanolamine; D003903:Deuterium; D000079:Acetaldehyde; C005398:phenoxyethanol