Dataset Information

Sodium lauryl ether sulfate (SLES) degradation by nitrate-reducing bacteria.

ABSTRACT: The surfactant sodium lauryl ether sulfate (SLES) is widely used in the composition of detergents and frequently ends up in wastewater treatment plants (WWTPs). While aerobic SLES degradation is well studied, little is known about the fate of this compound in anoxic environments, such as denitrification tanks of WWTPs, nor about the bacteria involved in the anoxic biodegradation. Here, we used SLES as sole carbon and energy source, at concentrations ranging from 50 to 1000 mg L-1, to enrich and isolate nitrate-reducing bacteria from activated sludge of a WWTP with the anaerobic-anoxic-oxic (A2/O) concept. In the 50 mg L-1 enrichment, Comamonas (50%), Pseudomonas (24%), and Alicycliphilus (12%) were present at higher relative abundance, while Pseudomonas (53%) became dominant in the 1000 mg L-1 enrichment. Aeromonas hydrophila strain S7, Pseudomonas stutzeri strain S8, and Pseudomonas nitroreducens strain S11 were isolated from the enriched cultures. Under denitrifying conditions, strains S8 and S11 degraded 500 mg L-1 SLES in less than 1 day, while strain S7 required more than 6 days. Strains S8 and S11 also showed a remarkable resistance to SLES, being able to grow and reduce nitrate with SLES concentrations up to 40 g L-1. Strain S11 turned out to be the best anoxic SLES degrader, degrading up to 41% of 500 mg L-1. The comparison between SLES anoxic and oxic degradation by strain S11 revealed differences in SLES cleavage, degradation, and sulfate accumulation; both ester and ether cleavage were probably employed in SLES anoxic degradation by strain S11.

SUBMITTER: Paulo AMS

PROVIDER: S-EPMC5486822 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature

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Sodium lauryl ether sulfate (SLES) degradation by nitrate-reducing bacteria.

Paulo Ana M S AMS Aydin Rozelin R Dimitrov Mauricio R MR Vreeling Harm H Cavaleiro Ana J AJ García-Encina Pedro A PA Stams Alfons J M AJM Plugge Caroline M CM

Applied microbiology and biotechnology 20170315 12

The surfactant sodium lauryl ether sulfate (SLES) is widely used in the composition of detergents and frequently ends up in wastewater treatment plants (WWTPs). While aerobic SLES degradation is well studied, little is known about the fate of this compound in anoxic environments, such as denitrification tanks of WWTPs, nor about the bacteria involved in the anoxic biodegradation. Here, we used SLES as sole carbon and energy source, at concentrations ranging from 50 to 1000 mg L<sup>-1</sup>, to ...[more]

PMID: 28299401

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Project description:BackgroundThe increasing number of patients with ovarian insufficiency due to autoimmune disorders, genetic predisposition, or iatrogenic effects of treatment such as cancer therapies necessitates an urgent measure to find a safe and transplantable alternative ovary. A bioengineered ovary is one of the strategies on which the researchers have recently been working. An engineered ovary should be able to mimic the natural ovary aspects. Recent studies suggest that the decellularized organ-specific extracellular matrix-based scaffolds can serve as a native niche to bioengineering artificial organs. Therefore, we established a human decellularized ovarian scaffold based on a sodium lauryl ester sulfate (SLES)-treated process, as an optimized protocol.MethodsThe human ovary samples were decellularized with 1% SLES for 48 h followed by DNase I in PBS for 24 h, and then thoroughly rinsed in PBS to remove the cell remnants and chemical reagents. Efficient cell removal was confirmed by DNA content analysis, hematoxylin and eosin, and Hoechst staining. Preservation assessment of the extracellular matrix structures was performed by immunohistochemistry, histological staining, and scanning electron microscopy. An MTT test was done to assess the in vitro scaffold's cytocompatibility, and finally in vivo studies were performed to evaluate the biocompatibility, bioactivity, and secretion functions of the ovarian grafts made of primary ovarian cells (POCs) on the decellularized scaffolds.ResultsEvidence provided by SEM, histochemical, and immunohistochemical analyses showed that the ovarian extracellular matrix was preserved after decellularization. Moreover, MTT test indicated the suitable cytocompatibility of the scaffolds. The in vivo assessment showed that the POCs kept their viability and bioactivity, and reconstructed the primordial or primary follicle-like structures within the scaffolds after transplantation. Immunostaining characterized somatic cells that were capable of expressing steroid hormone receptors; also, as a marker of granulosa cell, inhibin-α immunostaining demonstrated these cells within the grafts. Additionally, hormone assessment showed that serum estradiol and progesterone levels were significantly higher in ovariectomized rats with ovarian cells-seeded grafts than those with or without decellularized scaffold grafts.ConclusionsA human ovary-specific scaffold based on a SLES-decellularized protocol as a biomimicry of the natural ovarian niche can be an ideal scaffold used to reconstruct the ovary.

Project description:The occurrence of non-isoprenoid alkyl glycerol ether lipids in Bacteria and natural environments is increasingly being reported and the specificity and diagenetic stability of these lipids make them powerful biomarkers for biogeochemical and environmental studies. Yet the environmental controls on the biosynthesis of these peculiar membrane lipids remain poorly documented. Here, the lipid content of two mesophilic (Desulfatibacillum aliphaticivorans and Desulfatibacillum alkenivorans) and one thermophilic (Thermodesulfobacterium commune) sulfate-reducing bacteria-whose membranes are mostly composed of ether lipids-was investigated as a function of growth temperature (20-40°C and 54-84°C, respectively). For all strains, the cellular lipid content was lower at sub- or supra-optimal growth temperature, but the relative proportions of dialkyl glycerols, monoalkyl glycerols and fatty acids remained remarkably stable whatever the growth temperature. Rather than changing the proportions of the different lipid classes, the three strains responded to temperature changes by modifying the average structural composition of the alkyl and acyl chains constitutive of their membrane lipids. Major adaptive mechanisms concerned modifications of the level of branching and of the proportions of the different methyl branched lipids. Specifically, an increase in temperature induced mesophilic strains to produce less dimethyl branched dialkyl glycerols and 10-methyl branched lipids relative to linear structures, and the thermophilic strain to decrease the proportion of anteiso relative to iso methyl branched compounds. These modifications were in agreement with a regulation of the membrane fluidity. In one mesophilic and the thermophilic strains, a modification of the growth temperature further induced changes in the relative proportions of sn-2 vs sn-1 monoalkyl glycerols, suggesting an unprecedented mechanism of homeoviscous adaptation in Bacteria. Strong linear correlations observed between different ratios of alkyl glycerols and temperature allow to hypothesize the use of these specific lipids as indicators of temperature changes in the environment.

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Sodium lauryl ether sulfate (SLES) degradation by nitrate-reducing bacteria.

Publications

Sodium lauryl ether sulfate (SLES) degradation by nitrate-reducing bacteria.

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