Re-evaluation of the hypothesis that biodegradable surfactants stimulate surface attachment of competent bacteria.
The hypothesis that biodegradable surfactants stimulate the attachment of biodegradation-competent bacteria to surfaces has been re-evaluated using a variant of the surfactant-degrading bacterium Pseudomonas sp. DES1 designated Pseudomonas sp. DES2. This variant was identical to the parental strain in terms of its carbon-utilization patterns and alcohol dehydrogenase and alkylsulfatase complements (enzymes involved in surfactant biodegradation), but differed markedly in its growth characteristics when using sodium dodecyl triethoxysulfate or triethylene glycol dodecyl ether as secondary carbon sources. Pseudomonas sp. DES1 exhibited diauxie in these surfactant-based culture media in contrast to Pseudomonas sp. DES2, which exhibited single-phase growth. Pseudomonas sp. DES2 did not attach to river sediment in a microcosm system when challenged with a dose of either surfactant, although it did biodegrade the substrate. In contrast, Pseudomonas sp. DES1 attached to the river sediment whilst biodegrading the test substrate. It is concluded that the ether-scission system, which is responsible for primary biodegradation of both substrates, is deregulated in Pseudomonas sp. DES2 in contrast to that in Pseudomonas sp. DES1, and that, contrary, to a previous hypothesis, biodegradable surfactants do not necessarily stimulate the attachment of biodegradation-competent bacteria during their biodegradation.
Owen
Sarah A
SA
School of Molecular and Medical Biosciences, Biochemistry Unit, University of Wales Cardiff,PO Box 911, Cardiff CF1 3US,UK.
Russell
Nicholas J
NJ
School of Molecular and Medical Biosciences, Biochemistry Unit, University of Wales Cardiff,PO Box 911, Cardiff CF1 3US,UK.
House
W Alan
WA
Institute of Freshwater Ecology, River Laboratory,East Stoke, Wareham, Dorset BH20 6BB,UK.
White
Graham F
GF
School of Molecular and Medical Biosciences, Biochemistry Unit, University of Wales Cardiff,PO Box 911, Cardiff CF1 3US,UK.
D001422:Bacterial Adhesion / Q000187:drug effects*; D001426:Bacterial Proteins / Q000032:analysis; D001673:Biodegradation, Environmental; D019015:Geologic Sediments; D011092:Polyethylene Glycols / Q000378:metabolism; D011549:Pseudomonas / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D012967:Sodium Dodecyl Sulfate / Q000031:analogs & derivatives* / Q000494:pharmacology; D013429:Sulfatases / Q000378:metabolism; D013501:Surface-Active Agents / Q000494:pharmacology*; D014871:Water Microbiology
D001426:Bacterial Proteins; D013501:Surface-Active Agents; C017948:dodecyltriethoxy sulfate; D012967:Sodium Dodecyl Sulfate; D011092:Polyethylene Glycols; D013429:Sulfatases; C019244:alkylsulfatase