Anaerobic degradation of betaine by marineDesulfobacteriumstrains

✍ Scribed by J. H. F. G. Heijthuijsen; T. A. Hansen

• Publisher: Springer
• Year: 1989
• Tongue: English
• Weight: 587 KB
• Volume: 152
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00425179

✦ Synopsis

From enrichment cultures with betaine (20 mM) and sulfate (20 raM) as the substrates and intertidal mud as an inoculum, a betaine-oxidizing, sulfate-reducing bacterium (strain PM4) was isolated. Strain PM4 was an oval to rod-shaped, Gram-negative, motile bacterium, which was able to oxidize lactate completely to CO2 and contained, during growth on betaine and sulfate, high activities of key enzymes of the acetyl CoA/CO dehydrogenase pathway (carbon monoxide dehydrogenase and formate dehydrogenase), but not of 2-oxo-glutarate dehydrogenase, a key enzyme of the citric acid cycle. On the basis of its morphological and physiological characteristics, strain PM4 was identified as a Desulfobacterium strain. Desulfobacterium PM4 grew on betaine with a doubling time of approximately 20 h at 30 ~ C and produced N, N-dimethylglycine (in a 1 : 1 ratio) and sulfide as products. In this type of betaine metabolism one of the methyl groups of betaine is oxidized to COz and the reducing equivalents generated are used for the reduction of sulfate. Desulfobacterium autotrophicum (DSM 3382) grew also on betaine and sulfate with the formation of N,Ndimethylglycine, sulfide and CO2.