Initial Stages in the Biodegradation of the Surfactant Sodium Dodecyltriethoxy Sulfate by Pseudomonas sp. Strain DES1

Abstract

The biodegradation of the surfactant sodium dodecyltriethoxy sulfate by Pseudomonas sp., strain DES1 (isolated from activated sludge plant effluent) has been studied. Growth of the organism when the 35S-labeled surfactant was present as the sole source of carbon and energy led to the appearance in the culture fluid of five 35S-labeled organic metabolites. These have been identified as mono-, di-, and triethylene glycol monosulfates (major metabolites) and acetic acid 2-(ethoxy sulfate) and acetic acid 2-(diethoxy sulfate), authentic samples of which have been prepared and characterized. Evidence is presented that the major metabolites were produced by rupture of one or another of the three ether linkages present in the surfactant molecule, probably via the agency of a single etherase enzyme. Acetic acid 2-(ethoxy sulfate) and acetic acid 2-(diethoxy sulfate) were formed by the oxidation of the free alcohol groups of di-and triethylene glycol monosulfates, respectively, and increased in amount during the stationary phase of growth. Inorganic "S-sulfate also appeared in significant quantities in culture fluids and arose from the parent surfactant (presumably via the action of an alkylsulfatase) and not from any of the five metabolites. The appearance of sulfated organic metabolites during the exponential phase of growth and their quantitative relationship remained remarkably constant, even when additional carbon and energy sources (succinate or yeast extract) were also present in the growth media.

Surfactants and the environment

“…not involve hydrolytic cleavage of the sulphate group but rather cleavage of the ether linkage to provide a long-chain alcohol (subsequently biodegraded by mechanisms analogous to the PAS case) and a series of ethylene glycol sulphates which are in turn further metabolised (12). There is at present no evidence for the mechanism by which biodegradation of SAS occurs though, by analogy with other surfactants, initial w-oxidation followed by P-oxidation of the alkyl chain might be expected to occur.…”

Sulfate Ester Detergent Degradation inPseudomonas aeruginosaIs Subject to both Positive and Negative Regulation

“…Metabolite analysis in Pseudomonas sp. strain Des1 (38,39), Pseudomonas sp. strain SC25A (40), and P. nitroreducens (41) revealed that degradation starts with cleavage of the ether bonds, but cleavage of the sulfate ester bond has also been shown to occur concomitantly to ether cleavage in some of these strains (41,42).…”

Bioconversion of sodium dodecyl sulphate to rhamnolipids by transformedEscherichia coliDH5αcells-a novel strategy for rhamnolipid synthesis

“…A zymogram analysis of alkylsulfatase was also conducted using the whole protein content of S15. Fresh protein aliquots were used for native Polyacrylamide gel Analysis, followed by incubation of gel at 30°C in a solution containing 10 mmol l À1 SDS and 20 mmol l À1 BaCl 2 in 20 mmol l À1 Tris-HCl, pH 7Á8 (Hales et al 1982).…”

“…The plasmid DNA profiles of parent microbe and transformants were analyzed by agarose gel electrophoresis. The SDS degradation ability of S15 and transformant at protein level was finally confirmed by alkylsulfatase assay (Ellis et al 2002) and zymogram analysis (Hales et al 1982). Biosurfactant production ability of transformant was further analyzed by inoculating them on SCM plates and incubating at 30°C for 2-3 days.…”