Stable isotope probing as an effective tool for direct identification of active microorganisms in biofilters

• Autores: André Lipski, Julia Piehl, Michèle Friedrich
• Localización: Biotechniques for air pollution control: proceedings of the international congress Biotechniques for Air Pollution Control : A Coruña, Spain, October 5-7, 2005 / Christian Kennes (dir. congr.), María C. Veiga (dir. congr.), 2005, ISBN 84-9749-163-7, págs. 31-37
• Idioma: inglés
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  • Active styrene and hexane-degrading microorganisms in biofilters were directly characterized without cultivation. For direct probing biofilter material samples were incubated with deuterated substrates. These substrates were rapidly assimilated by the degrading microbial populations and incorporated in chemotaxonomically relevant cell lipids. Phospholipid fatty acids were extracted from the filter material and labeled fatty acids were recognized by gas chromatography-mass spectrometry. The spectrum of labeled fatty acids was compared with the fatty acid profiles of cultivated isolates to assess the relevance of the isolated microorganisms for the degradation process. From styrene treated biofilters we could isolate several styrene degrading strains from various taxonomic groups. However, none of the isolates showed a fatty acid pattern similar to the set of labeled lipids from the filter material. Fatty acid analyses of the enrichment cultures revealed that labeled lipids were rapidly lost during the enrichment procedure. In contrast, for a hexane-degrading biofilter the direct probing approach identified a defined group of isolates as apparent hexane degraders of the full scale bio-filtration process. Isolates with matching fatty acid profiles were identified as members of the genus Gordonia.Other isolates with high hexane degrading activities in artificial media were predominantly assigned to the Proteobacteria. According to their deviating fatty acid profiles most of these strains could be excluded from the group of important biocatalysts in the filtration process.