Titre du document / Document title
Metabolic characteristics of an aerobe isolated from a methylotrophic methanogenic enrichment culture
Auteur(s) / Author(s)RAPHEAL Stephen V.
SWAMINATHAN K. R.
Résumé / Abstract
An anaerobic methylotrophic methanogenic enrichment culture, with sustained metabolic characteristics, including that of methanation for over a decade, was the choice of the present study on interspecies interactions. Growth and methanation by the enrichment were suppressed in the presence of antibiotics, and no methanogen grown on methanol could be isolated using stringent techniques. The present study confirmed syntrophic metabolic interactions in this enrichment with the isolation of a strain of Pseudomonas sp. The organism had characteristic metabolic versatility in metabolizing a variety of substrates including alcohols, aliphatic acids, amino acids, and sugars. Anaerobic growth was favoured with nitrate in the growth medium. Cells grown anaerobically with methanol, revealed maximal nitrate reductase activity. Constitutive oxidative activity of the membrane system emerged from the high-specific oxygen uptake and nitrate reductase activities of the aerobically and anerobically grown cells respectively. Cells grown anaerobically on various alcohols effectively oxidized methanol in the presence of flavins, cofactor FAD and the methanogenic cofactor F420
, suggesting a constitutive alcohol oxidizing capacity. In cells grown anaerobically on methanol, the rate of methanol oxidation with F420
was three times that of FAD. Efficient utilization of alcohols in the presence of F420
is a novel feature of the present study. The results suggest that utilization of methanol by the mixed culture would involve metabolic interactions between the Pseudomonas sp. and the methanogen(s). Methylotrophic, methanogenic partnership involving an aerobe is a novel feature hitherto unreported among anaerobic syntrophic associations and is of ecological significance.
Revue / Journal TitleJournal of biosciences
Source / Source
2003, vol. 28, no
2, pp. 235-242 [8 page(s) (article)]
Langue / Language
Editeur / Publisher
Indian Academy of Sciences, Bangalore, INDE
Localisation / Location
INIST-CNRS, Cote INIST : 573 C, 35400011843845.0110
Nº notice refdoc (ud4) : 14880686