Desulfonation and degradation of the disulfodiphenylethercarboxylates from linear alkyldiphenyletherdisulfonate surfactants

Detections of alkyl-phenoxy-benzenesulfonates in municipal wastewater

This study presents the first reported detections and concentrations of alkyl phenoxy-benzenesulfonate surfactants (APBS) in municipal wastewater. A semi quantitative direct injection LC/MS/MS method was developed. Samples of raw influent and final effluent were obtained from fourteen municipal wastewater treatment plants (WWTPs) at various locations in Canada and were analyzed for APBS, including five homologues of monoalkyldiphenylether disulfonates (MADS) and one monoalkyldiphenylether sulfonate (MAMS) homologue. APBS were detected in all 42 of the wastewater raw influent samples and in 37 of the 42 wastewater final effluent samples; the other 5 final effluent samples had trace levels below the minimum detection limit. In the samples of raw influent from the fourteen municipal treatment plants, the dissolved concentrations of APBS (total) ranged from 0.9 to 13.6 μg/L. In samples of final effluent from the same plants the total APBS ranged from below detection to 4 μg/L. The APBS were more resistant to loss during wastewater treatment compared to previous studies of linear alkylbenzene sulfonates in wastewaters. The most effective wastewater treatments for removal of APBS were those that involved either secondary treatment with aeration or advanced treatment including biological nutrient removal. Available information on ecotoxicity is lacking for evaluating the impacts of APBS surfactants when released to the environment.

Detergent-like stressor and nutrient in metabolism of Penicillium chrysogenum

The influence of detergents on the metabolism of Penicillium chrysogenum from two aspects, as a stress factor and potential nutrient, was studied. The fungus was isolated from the river bed Lepenica, Kragujevac, at a place where sewage domestic wastewater discharged into the river. The fungus was grown in a liquid nutrient medium according to Czapek with and without addition of commercial detergent (MERIX, Henkel, Serbia) at a concentration of 0.3% and 0.5%. The biochemical changes of pH, redox potential, free and total organic acids, total dry weight biomass, activity of alkaline and acid invertase and alkaline phosphatase were evaluated from day 3 to day 16 of the fungus growth. At the same time, detergent disappearance in terms of methylene blue active substances in the medium was measured. The detergent at a concentration of 0.5% showed a fungicide effect. In the medium with 0.3% of detergent, there was increased pH and concentration of organic acids, but decreased redox potential and total dry weight biomass. The detergent also showed an inhibitory effect on invertase and phosphatase activity. P. chrysogenum decomposed 50.2% of the total detergent concentration for an experimental period of 16 days.

Screening of SDS-degrading bacteria from car wash wastewater and study of the alkylsulfatase enzyme activity

BACKGROUND AND OBJECTIVES

Sodium dodecyl sulfate (SDS) is one of the main surfactant components in detergents and cosmetics, used in high amounts as a detergent in products such as shampoos, car wash soap and toothpaste. Therefore, its bioremediation by suitable microorganisms is important. Alkylsulfatase is an enzyme that hydrolyses sulfate -ester bonds to give inorganic sulfate and alcohol. The purpose of this study was to isolate SDS-degrading bacteria from Tehran city car wash wastewater, study bacterial alkylsulfatase enzyme activity and identify the alkylsulfatase enzyme coding gene.

MATERIALS AND METHODS

Screening of SDS-degrading bacteria was carried out on basal salt medium containing SDS as the sole source of carbon. Amount of SDS degraded was assayed by methylene blue active substance (MBAS).

RESULTS AND CONCLUSION

Identification of the sdsA gene was carried by PCR and subsequent sequencing of the 16S rDNA gene and biochemical tests identified Pseudomonas aeruginosa. This bacterium is able to degrade 84% of SDS after four days incubation. Bacteria isolated from car wash wastewater were shown to carry the sdsA gene (670bp) and the alkylsulfatase enzyme specific activity expressed from this gene was determined to be 24.3 unit/mg. The results presented in this research indicate that Pseudomonas aeruginosa is a suitable candidate for SDS biodegradation.

Complete genome sequence of Parvibaculum lavamentivorans type strain (DS-1(T))

Parvibaculum lavamentivorans DS-1(T) is the type species of the novel genus Parvibaculum in the novel family Rhodobiaceae (formerly Phyllobacteriaceae) of the order Rhizobiales of Alphaproteobacteria. Strain DS-1(T) is a non-pigmented, aerobic, heterotrophic bacterium and represents the first tier member of environmentally important bacterial communities that catalyze the complete degradation of synthetic laundry surfactants. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 3,914,745 bp long genome with its predicted 3,654 protein coding genes is the first completed genome sequence of the genus Parvibaculum, and the first genome sequence of a representative of the family Rhodobiaceae.

Microbial conversion of 5-sulfoisophthalic acid into 5-hydroxyisophthalic acid by Ochrobactrum anthropi S9

5-Hydroxyisophthalic acid-producing microorganisms were isolated from enrichment cultures using 5-sulfoisophthalic acid as a sulfur source. One bacterium, Ochrobactrum anthropi S9, had the highest 5-sulfoisophthalic acid-degrading activity, and stoichiometrically formed 5-hydroxyisophthalic acid, a raw material for polymer synthesis. Under optimum culture conditions, 1.3 mM 5-hydroxyisophthalic acid accumulated in the medium by 60 h. The addition of Na(2)SO(4), L: -methionine or L: -cysteine at 2 mM inhibited the conversion of 5-sulfoisophthalic acid. O. anthropi S9 cells converted 5-sulfoisophthalic acid, benzenesulfonic acid, 3-sulfobenzoic acid, 4-aminobenzenesulfonic acid, naphthalene-1-sulfonic acid and naphthalene-2-sulfonic acid into the corresponding hydroxylated compounds.

Sulfonate desulfurization in Rhodococcus from wheat rhizosphere communities

Organically bound sulfur makes up about 90% of the total sulfur in soils, with sulfonates often the dominant fraction. Actinobacteria affiliated to the genus Rhodococcus were able to desulfonate arylsulfonates in wheat rhizospheres from the Broadbalk long-term field wheat experiment, which includes plots treated with inorganic fertilizer with and without sulfate, with farmyard manure, and unfertilized plots. Direct isolation of desulfonating rhizobacteria yielded Rhodococcus strains which grew well with a range of sulfonates, and contained the asfAB genes, known to be involved in sulfonate desulfurization by bacteria. Expression of asfA in vitro increased >100-fold during growth of the Rhodococcus isolates with toluenesulfonate as sulfur source, compared with growth with sulfate. By contrast, the closely related Rhodococcus erythropolis and Rhodococcus opacus type strains had no desulfonating activity and did not contain asfA homologues. The overall actinobacterial community structure in wheat rhizospheres was influenced by the sulfur fertilization regime, as shown by specific denaturing gradient gel electrophoresis of PCR amplified 16S rRNA gene fragments, and asfAB clone library analysis identified nine different asfAB genotypes closely affiliated to the Rhodococcus isolates. However, asfAB-based multiplex restriction fragment length polymorphism (RFLP)/terminal-RFLP analysis of wheat rhizosphere communities revealed only slight differences between the fertilization regimes, suggesting that the desulfonating Rhodococcus community does not specifically respond to changes in sulfate supply.

Parvibaculum lavamentivorans DS-1T degrades centrally substituted congeners of commercial linear alkylbenzenesulfonate to sulfophenyl carboxylates and sulfophenyl dicarboxylates

Commercial linear alkylbenzenesulfonate (LAS) contains 20 congeners of linear alkanes (C(10) to C(13)) substituted subterminally with the 4-sulfophenyl moiety in any position from lateral to central. Parvibaculum lavamentivorans DS-1(T) degrades each of eight laterally substituted congeners [e.g., 2-(4-sulfophenyl)decane (2-C10-LAS); herein, compounds are named systematically by chain length (e.g., C(10)) and by the position of the substituent on the chain (e.g., position 2)] to a major sulfophenyl carboxylate [SPC; here 3-(4-sulfophenyl)butyrate (3-C4-SPC)] and two minor products, namely, the alpha,beta-unsaturated SPC (SPC-2H, here 3-C4-SPC-2H) and the SPC+2C (here 5-C6-SPC) species (D. Schleheck, T. P. Knepper, K. Fischer, and A. M. Cook, Appl. Environ. Microbiol. 70:4053-4063). The degradation of centrally substituted congeners by strain DS-1 was examined in this work. 5-C10-LAS yielded not only the predicted 4-C8-SPC, 4-C8-SPC-2H, and 6-C10-SPC (about 70% of products) but also sulfophenyl dicarboxylates (SPdC), i.e., C6-, C8-, and C10-SPdC. These were identified by electrospray ionization-mass spectrometry (ESI-MS) after separation by high-pressure liquid chromatography (HPLC). ESI ion-trap MS and ESI-time of flight-MS were used to confirm the identities of key intermediates. Different mixtures of congeners obtained by separation of commercial LAS by HPLC were degraded, and the degradative products were compared. If a congener carried the sulfophenyl substituent on the 5, 6, or 7 position, SPdCs were formed as well as SPC, SPC-2H, and SPC+2C, whereas the substituent on the 2, 3, or 4 position yielded only SPC, SPC-2H, and SPC+2C. Some 50 products were generated from the 20 LAS congeners: 11 major SPCs, each with an SPC-2H and an SPC+2C (i.e., 33 SPC and SPC-2H species), and about 17 SPdC species. A large array of compounds, many in low quantities, is thus generated by P. lavamentivorans DS-1 during the degradation of commercial LAS.

Desulfurization of aromatic sulfonates by rhizosphere bacteria: high diversity of the asfA gene

The plant growth-promoting effect of Pseudomonas putida S-313 is associated with its ability to desulfurize arylsulfonates. To understand this further, other plant-associated bacteria able to desulfurize a range of arylsulfonates were isolated from the rhizospheres of winter and spring barley. The isolates belonged to the beta-proteobacteria, including bacteria from the Variovorax paradoxus group and from the Acidovorax genus. They desulfurized toluenesulfonate to p-cresol, and were found to contain orthologues of the P. putida S-313 asfA gene (> 70% sequence identity to AsfA), which is required for aryldesulfonation in this species. Further putative asfA orthologues were identified in several bacteria and cyanobacteria whose genomes have been sequenced, but of these only Cupriavidus (Ralstonia) metallidurans was able to utilize arylsulfonates as sulfur source. Cultivation of V. paradoxus, C. metallidurans or P. putida S-313 with toluenesulfonate as sulfur source led to a 100-fold increase in expression of the asfA homologues, which was largely repressed when sulfate was added. Polymerase chain reaction with degenerate primers was used to generate asfAB clone libraries from spring- and winter-barley rhizosphere DNA. Cluster analysis of 76 sequenced AsfA fragments revealed a broad diversity, with the majority of the sequences clustered together with AsfA from bacteria that are able to utilize toluenesulfonate as sulfur source. The diversity of asfA in barley rhizosphere underlines the importance of the desulfonation process for bacteria that inhabit the plant rhizosphere.

Biodegradation of Sodium Lauryl Ether Sulfate (SLES) by Two Different Bacterial Consortia

Two bacterial consortia capable of degrading SLES were isolated from a wastewater treatment plant. The two consortia consisted of three members, Acinetobacter calcoacetiacus and Klebsiella oxytoca in one co-culture (A-K) and Serratia odorifera in the second co-culture (S-A), which contains Acinetobacter calcoacetiacus as well. In all experiments, cells were grown on SLES (1000-7000 ppm) containing the M9 minimal medium as sole carbon source. The co-culture A-K demonstrated a higher growth rate (0.26 h(-1)) and significant greater viability than that of the co-culture S-A (0.21 h(-1)). Glucose, sucrose, maltose, mannitol, and succinic acid as carbon sources produced the same degradation rate (approximately 100 ppm/h) and enhanced the SLES degradation rate by 3-fold upon the control (without an added carbon source). In the case of the co-culture S-A, the situation was different; all the carbon sources being tested except maltose caused a repression in the degradation ability in a range between 25-100%. Maltose causes an enhancement by almost fivefold, compared with the positive control.

Sulfatases: Structure, Mechanism, Biological Activity, Inhibition, and Synthetic Utility

Sulfatases, which cleave sulfate esters in biological systems, play a key role in regulating the sulfation states that determine the function of many physiological molecules. Sulfatase substrates range from small cytosolic steroids, such as estrogen sulfate, to complex cell-surface carbohydrates, such as the glycosaminoglycans. The transformation of these molecules has been linked with important cellular functions, including hormone regulation, cellular degradation, and modulation of signaling pathways. Sulfatases have also been implicated in the onset of various pathophysiological conditions, including hormone-dependent cancers, lysosomal storage disorders, developmental abnormalities, and bacterial pathogenesis. These findings have increased interest in sulfatases and in targeting them for therapeutic endeavors. Although numerous sulfatases have been identified, the wide scope of their biological activity is only beginning to emerge. Herein, accounts of the diversity and growing biological relevance of sulfatases are provided along with an overview of the current understanding of sulfatase structure, mechanism, and inhibition.

Mineralization of individual congeners of linear alkylbenzenesulfonate by defined pairs of heterotrophic bacteria

Parvibaculum lavamentivorans DS-1(T) utilized the commercial surfactant linear alkylbenzenesulfonate (LAS) (20 congeners with C(10) to C(13) side chains) as a carbon and energy source by shortening the side chain, and sulfophenylcarboxylates (SPCs) and similar compounds (e.g., alpha,beta-unsaturated SPCs [SPC-2Hs]) were excreted with quantitative recovery of the sulfophenyl moiety. 2-(4-Sulfophenyl)decane (2-C10-LAS) was converted largely to 3-(4-sulfophenyl)butyrate (3-C4-SPC), as were 2-C12-LAS and 2-C14-LAS; the other products were 5-C6-SPC (SPC+2C) and 3-C4-SPC-2H. 2-C11-LAS was converted largely to 4-C5-SPC with the corresponding SPC+2C and SPC-2H; similarly, 3-C12-LAS yielded 4-C6-SPC with the corresponding SPC+2C and SPC-2H. This pattern of products confirmed that LAS is degraded by omega-oxygenation and chain shortening through beta-oxidation. At least nine major SPCs were formed from commercial LAS. The novel isolates Comamonas testosteroni SPB-2 and KF-1 utilized 3-C4-SPC; Delftia acidovorans SPH-1 utilized 4-C6-SPC enantioselectively. The substrate-dependent oxygen uptake of whole cells of strain SPB-2 indicated that there was inducible oxygenation of 3-C4-SPC and of 4-sulfophenol in whole cells of the strains of C. testosteroni during growth with 3-C4-SPC or 4-sulfophenol. The degradative pathways apparently involved 4-sulfocatechol and 4-sulfocatechol 1,2-dioxygenase. Strain SPB-2 and strain DS-1(T) grew together in LAS-salts medium, and only seven of the nine major SPCs were recovered. Strain SPB-2 utilized 3-C4-SPC, 3-C5-SPC, and 3-C4-SPC-2H. Strain SPH-1 grew together with strain DS-1(T) in LAS-salts medium, and a different set of seven major SPCs was recovered. Strain SPH-1 utilized 4-C6-SPC, 4-C5-SPC, 4-C6-SPC-2H, and 4-C5-SPC-2H. A three-member community consisting of strains DS-1(T), SPB-2, and SPH-1 utilized four major SPCs. We inferred that this community mineralized the major SPCs derived from 8 of the 20 LAS congeners.

Parvibaculum lavamentivorans gen. nov., sp. nov., a novel heterotroph that initiates catabolism of linear alkylbenzenesulfonate

Strain DS-1T is a small (0·8 μm in length and 0·2 μm in diameter) heterotrophic bacterium able to ω-oxygenate the commercial surfactant linear alkylbenzenesulfonate (LAS) and shorten the side chain by β-oxidation to yield sulfophenylcarboxylates. The morphotype is widespread in cultures able to utilize LAS, and a second organism with similar characteristics, strain AN-8, is now available. Utilization of LAS is concomitant with formation of a biofilm, and cells were non-motile. Many surfactants were utilized. The organisms also grew with acetate or octane, but required no biofilm and were motile. Analysis of the gene encoding 16S rRNA placed the organisms in the α-subclass of the Proteobacteria with a sequence divergence of >8 % from any species whose name has been validly published. 16S rRNA gene sequence comparison with entries in the GenBank database showed 98 % similarity to an α-protobacterial marine isolate, JP57: strain JP57 displayed the same morphotype as strain DS-1T, but it was unable to utilize surfactants or any single source of carbon tested. The lipid components of strains DS-1T and JP57 were virtually identical. The fatty acids contained ester- and putative amide-linked hydroxy fatty acids, in a combination that is currently unique in the α-Proteobacteria. The major respiratory quinone present in both strains was Q11. The polar lipids consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine and two unidentified aminolipids. Data on the 16S rRNA gene sequence and the lipid composition indicated that strains DS-1T and JP57 should be placed in a new genus, for which the name Parvibaculum is proposed. The differences between these strains, supported by DNA hybridizations, lead to the conclusion that strain DS-1T (=DSM 13023T=NCIMB 13966T) is the type strain of a species in the genus Parvibaculum, for which the name Parvibaculum lavamentivorans gen. nov., sp. nov. is proposed.

Rhodococcus opacus expresses the xsc gene to utilize taurine as a carbon source or as a nitrogen source but not as a sulfur source

The Gram-positive bacteria Rhodococcus opacus ISO-5 and Rhodococcus sp. RHA1 utilized taurine (2-aminoethanesulfonate) as the sole source of carbon or of nitrogen or of sulfur for growth. Different gene clusters and enzymes were active under these different metabolic situations. Under carbon- or nitrogen-limited conditions three enzymes were induced, though to different levels: taurine-pyruvate aminotransferase (Tpa), alanine dehydrogenase (Ald) and sulfoacetaldehyde acetyltransferase (Xsc). The specific activities of these enzymes in R. opacus ISO-5 were sufficient to explain the growth rates under the different conditions. These three enzymes were purified and characterized, and the nature of each reaction was confirmed. Analyses of the genome of Rhodococcus sp. RHA1 revealed a gene cluster, tauR-ald-tpa, putatively encoding regulation and oxidation of taurine, located 20 kbp from the xsc gene and separate from two candidate phosphotransacetylase (pta) genes, as well as many candidate ABC transporters (tauBC). PCR primers allowed the amplification and sequencing of the tauR-ald-tpa gene cluster and the xsc gene in R. opacus ISO-5. The N-terminal sequences of the three tested proteins matched the derived amino acid sequences of the corresponding genes. The sequences of the four genes found in each Rhodococcus strain shared high degrees of identity (>95 % identical positions). RT-PCR studies proved transcription of the xsc gene when taurine was the source of carbon or of nitrogen. Under sulfur-limited conditions no xsc mRNA was generated and no Xsc was detected. Taurine dioxygenase (TauD), the enzyme catalysing the anticipated desulfonative reaction when taurine sulfur is assimilated, was presumed to be present because oxygen-dependent taurine disappearance was demonstrated with taurine-grown cells only. A putative tauD gene (with three other candidates) was detected in strain ISO-5. Regulation of the different forms of metabolism of taurine remains to be elucidated.

Parvibaculum lavamentivorans converts linear alkylbenzenesulphonate surfactant to sulphophenylcarboxylates, alpha,beta-unsaturated sulphophenylcarboxylates and sulphophenyldicarboxylates, which are degraded in communities

AIMS

The aims were to test whether Parvibaculum lavamentivoransT degraded commercial linear alkylbenzenesulphonate (LAS) surfactant via omega-oxygenation and beta-oxidation to sulphophenylcarboxylates (SPCs), whether the organism was widespread and reisolable, and whether the degradative community used the 4-sulphocatechol 1,2-dioxygenase to cleave the aromatic ring from LAS.

METHODS AND RESULTS

Heterotrophic P. lavamentivoransT converted LAS (side chain length C10-C13) to SPCs (C4-C13), alpha,beta-unsaturated SPCs (C4-C13) and sulphophenyldicarboxylates (SPdCs) (at least C8-C12). Identifications came from high performance liquid chromatography (HPLC) separation, an electrospray interface and mass spectrometry. No evidence for other paths was found. The degradation of LAS in trickling filters inoculated with environmental samples always showed transient SPC intermediates (HPLC) and the presence of the P. lavamentivorans morphotype in the community. One new isolate was obtained. A community able to mineralize LAS contained 4-sulphocatechol-1,2-dioxygenase at high specific activity.

CONCLUSIONS

Parvibaculum lavamentivoransT degrades commercial LAS via omega-oxygenation, oxidation and chain shortening through beta-oxidation to yield a wide range of SPCs. The latter are degraded in bacterial communities which contain organisms like P. lavamentivorans, and which utilize sulphocatechol dioxygenase for ring cleavage.

SIGNIFICANCE AND IMPACT OF THE STUDY

There is one widespread pathway to degrade LAS. Any traces of LAS and larger amounts of SPCs in the effluent from sewage works are exposed to degradative organisms in acclimated and pristine environments. These degradative reactions can now be studied in pure cultures.