Interactions between vascular actions of detergent and catecholamines in perfused gills of European eel, Anguilla anguilla L. and brown trout, Salmo trutta L.

Noradrenaline induced vasodilation in isolated perfused eel or trout gills was inhibited by propranolol, aβ-adrenergic blocking agent. The noradrenaline effect was much reduced in gills of fish which had been kept in 1 mg/l solutions of the detergent LAS (linear alkylate sulphonate; 12C chain length). LAS produced concentration-dependent vasodilation, which was inhibited by propranolol, in eel and trout gills. Noradrenaline produced additional vasodilation in eel and trout gills which had been dilated by 2.10⁻⁸ m LAS but had no effect on trout gills perfused with 2.10⁻⁷ m LAS. Gills from trout which had been kept in 0.1 mg l^-1 LAS responded to noradrenaline normally but the propranolol inhibition appeared to be potentiated.     

Vascular effects of acetylcholine, catecholamines and detergents on isolated perfused gills of pink salmon, Oncorhynchus gorbuscha coho salmon, O. kisutch and chum salmon, O. keta

Acetylcholine caused vasoconstriction whilst adrenaline and isoprenaline caused vasodilation in isolated perfused Pacific salmon gills. The detergent LAS produced concentration dependent vasodilation when present in the perfusate in concentrations of 0.6 to 3 mg 1⁻¹. The effect of LAS was partly blocked by propranalol suggesting the involvement of β-adrenergic receptors. The maximum responses obtained with acetylcholine, adrenaline or LAS were all much greater in sea water or pre-spawning freshwater fish than in spawning fish.     

Enrichment of linear alkylbenzenesulphonate (LAS) degrading bacteria in continuous culture

Enrichment experiments were carried out in continuous-flow units using a mineral medium with commercial linear alkylbenzenesulphonate (LAS) as the limiting carbon- and energy-source. The mixed bacterial culture originating from the waste water of a detergent plant consisted of five strains belonging to the genus Pseudomonas and two strains each of the genera Achromobacter and Acinetobacter. The cultivation conditions corresponding to dilution rates of 0.025-0.1 h^-1 and LAS concentrations of 20–50 mg/1 were examined. During the experiments the composition of mixed cultures and the kinetics of LAS biodegradation were followed. Continuous-flow enrichment experiments resulted in the selection of six bacterial cultures with different compositions of individual species and capability to utilize LAS. From the original seven strains at lower dilution rates (0.025 and 0.05 h^-1) six were selected, excluding Pseudomonas sp. 3, while at the highest dilution rate (0.1/h^-1) five strains were selected after eliminating Pseudomonas sp. 5 and Achromobacter sp. 1. All enriched mixed cultures were more efficient in primary than in ultimate LAS degradation. Two of the culture strains were able to achieve primary LAS degradation ( Pseudomonas sp. 1 in mineral medium with LAS as the sole carbon- and energy-source and Acinetobacter sp. 3 in medium supplemented by yeast extract and nutrient broth).
None of the strains could degrade LAS completely, which indicates that many types of interactions based on combined metabolic attack as well as those based on provision of specific nutrients, may exist between culture members during the complete LAS bio-oxidation.     

塔式生物滤池处理洗涤剂工业废水的模拟试验

本项研究工作表明,塔式生物滤池在处理模拟洗涤剂工业废水时,能够适应和克服一般好氧生化法所不能解决的泡沫问题,并对废水中的LAS和COD具有一定的去除效果。根据实验结果,初步认为塔滤可应用于洗涤剂工业废水的生化处理,并向洗涤剂行业首次推荐这种废水生物学净化方法。从塔滤的生物膜中分离出了优势菌,经鉴定为一种气单胞菌(Aeromonas sp. D-4)。     

Influence of the Linear Alkylbenzene Sulfonate (LAS) on hematological and biochemical parameters of Nile Tilapia,Oreochromis niloticus

The acute toxicity of household detergent (Ariel) on blood parameters and histology of Oreochromis niloticus was investigated using static bioassay for 96 h. Linear alkylbenzene sulfonate (LAS) is an anionic surfactant widely used in detergents and cleaners, both in industrial and household applications. LAS contaminating aquatic ecosystems as a potential toxic pollutant, was investigated in the present study for acute toxicity. The fish samples were divided into six groups, including 20 fish in each group. Normal feed was given to control group without detergents treatment. Hematological parameters (RBC count, Hb, Ht and platelets) were significantly declined, while WBC count showed a highly significant increase. Compared with the control group, significant elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) was recorded in fish treated with different concentrations of detergent. Catalase (CAT), Superoxide dismutase (SOD) activities and Reduced Glutathione (GSH) concentration showed a highly significant reduction. Total proteins showed significant decrease, while total lipids, cholesterol and triglycerides significantly increased. The mean lethal concentration (LC₅₀) for 96 h of Ariel was at concentration 10 mg/L. Relative percentage of detergent residues in fish muscles was increased with higher detergent concentrations. In conclusion, exposure to detergents resulted in great alterations in the histological structure of liver and gills.     

Metabolism of Some Anionic Tallow-based Detergents by Sewage Microorganisms

A method in which the test detergent was the sole source of carbon was used to study the metabolism of several tallow-based detergents. These were tallow alcohol sulfates, long-chain ether alcohol sulfates, and esters of alpha-sulfo fatty acids. Sodium p-(1-methylundecyl)benzenesulfonate (LAS) was used as a reference material. The alcohol sulfates were the most rapidly and completely metabolized (96 to 99%), and one ether alcohol sulfate was 94% degraded. The other compounds were metabolized to the extent of 61 to 87%; LAS was 80% degraded. Except for the alcohol sulfates, loss of methylene blue activity (MBAS) occurred long before the chemical oxygen demand (COD) values had reached a minimum; with the alcohol sulfates, MBAS and COD decreased simultaneously.     

A comparative study of the unfolding of the endoglucanase Cel45 from Humicola insolens in denaturant and surfactant.

Cellulases are increasingly being used for industrial purposes, particularly in washing powders, yet little is known of the factors governing the stability of proteins in detergent solutions. We present a comparative analysis of the behavior of the cellulase Cel45 from Humicola insolens in the presence of the denaturant guanidinium chloride and the anionic detergent C12-LAS. Although Cel45 unfolds in GdmCl according to a simple two-state model under equilibrium conditions, it accumulates a transient intermediate during refolding. The four disulfide bonds do not contribute detectably to the stability of the native state. Cel45 is unfolded by very low concentrations of C12-LAS (1-4 mM). An analysis of 16 mutants of Cel45 shows a very weak correlation between unfolding rates in denaturant and detergent; mutants that have the same unfolding rate in GdmCl (within a factor of 1.5) vary 1,000-fold in their unfolding rates in C12-LAS. The data support a simple model for unfolding by detergent, in which the introduction of positive charges or removal of negative charges greatly increases detergent sensitivity, while interactions with the hydrophobic detergent tail contribute to a smaller extent. This implies that different detergent-mediated unfolding pathways exist, whose accessibilities depend on individual residues. Double-mutant cycles reveal that mutations in two proximal residues lead to repulsion and a destabilization greater than the sum of the individual mutations as measured by GdmCl denaturation, but they also reduce the affinity for LAS and therefore actually stabilize the protein relative to wild-type. Ligands that interact strongly with the denatured state may therefore alter the unfolding process.     

直链烷基苯磺酸盐(LAS)的生物降解性

阴离子表面活性剂直链烷基苯磺酸盐（LAS）在工业生产和人们生活中得到了广泛应用,但大量产生的含有LAS的污水在环境中造成的污染也日益严重,因而引起了人们的高度重视,本从LAS的好氧和厌氧生物降解以及LAS降解菌等诸多方面阐述了LAS生物降解性的研究进展。     

Isolation of (S)-2,3-dichloro-1-propanol assimilating bacterium,its characterization,and its use in preparation of (R)-2,3-dichloro-1-propanol and (S)-epichlorohydrin

Summary Linear alkylbenzene sulfonate (LAS) is a widely used anionic surfactant. Although approximately 1 million metric tons of LAS are produced annually, relatively little is known about the bacteria or the genetic factors that control LAS degradation in the environment. The objectives of this research were to: i) compare bacterial populations in wastewater and pristine pond systems; ii) determine the frequency of plasmids in bacteria from these sites; and iii) compare the frequency of DNA sequences coding for aromatic catabolism in isolates from these two sites. Plate counts indicated that exposure to wastewater resulted in higher levels of both heterotrophic bacteria and bacteria capable of growing on LAS containing medium (LAS/YEPG). In addition to higher numbers, a higher proportion of heterotrophs from the wastewater system were capable of growth on LAS/YEPG medium. Thus, the high levels of LAS in the wastewater system apparently selected fro organisms that were able to tolerate and/or degrade, it. Mineralization of¹⁴C-ring labelled LAS in any habitat related to the presence of organisms that grew on LAS/YEPG. Although may of these isolates could carry out primary degradation, no isolate, could mineralize¹⁴C-ring LAS in pure culture. A higher incidence of plasmids was found in bacteria from the wastewater pond and among bacteria that grew on LAS containing medium. However, the presence of plasmid, DNA did not necessarily confer the ability to degrade LAS nor was the ability to degrade LAS dependent on the presence of a plasmid. The incidence of selected genotypes for aromatic catabolism was similar among isolates on LAS/YEPG at both sites, suggesting that LAS ring degradation may be present in other populations or encoded by alternative sequences. In conclusion, LAS mineralization is mediated by a consortium and the evidence that initial attack of LAS is plasmid mediated is inconclusive.     

Toxic effects of linear alkylbenzene sulfonate on metabolic activity, growth rate, and microcolony formation of Nitrosomonas and Nitrosospira strains

Strong inhibitory effects of the anionic surfactant linear alkylbenzene sulfonate (LAS) on four strains of autotrophic ammonia-oxidizing bacteria (AOB) are reported. Two Nitrosospira strains were considerably more sensitive to LAS than two Nitrosomonas strains were. Interestingly, the two Nitrosospira strains showed a weak capacity to remove LAS from the medium. This could not be attributed to adsorption or any other known physical or chemical process, suggesting that biodegradation of LAS took place. In each strain, the metabolic activity (50% effective concentration [EC(50)], 6 to 38 mg liter(-1)) was affected much less by LAS than the growth rate and viability (EC(50), 3 to 14 mg liter(-1)) were. However, at LAS levels that inhibited growth, metabolic activity took place only for 1 to 5 days, after which metabolic activity also ceased. The potential for adaptation to LAS exposure was investigated with Nitrosomonas europaea grown at a sublethal LAS level (10 mg liter(-1)); compared to control cells, preexposed cells showed severely affected cell functions (cessation of growth, loss of viability, and reduced NH(4)(+) oxidation activity), demonstrating that long-term incubation at sublethal LAS levels was also detrimental. Our data strongly suggest that AOB are more sensitive to LAS than most heterotrophic bacteria are, and we hypothesize that thermodynamic constraints make AOB more susceptible to surfactant-induced stress than heterotrophic bacteria are. We further suggest that AOB may comprise a sensitive indicator group which can be used to determine the impact of LAS on microbial communities.     

Toxic Effects of Linear Alkylbenzene Sulfonate on Metabolic Activity, Growth Rate, and Microcolony Formation of Nitrosomonas and Nitrosospira Strains

Strong inhibitory effects of the anionic surfactant linear alkylbenzene sulfonate (LAS) on four strains of autotrophic ammonia-oxidizing bacteria (AOB) are reported. Two Nitrosospira strains were considerably more sensitive to LAS than two Nitrosomonas strains were. Interestingly, the two Nitrosospira strains showed a weak capacity to remove LAS from the medium. This could not be attributed to adsorption or any other known physical or chemical process, suggesting that biodegradation of LAS took place. In each strain, the metabolic activity (50% effective concentration [EC₅₀], 6 to 38 mg liter⁻¹) was affected much less by LAS than the growth rate and viability (EC₅₀, 3 to 14 mg liter⁻¹) were. However, at LAS levels that inhibited growth, metabolic activity took place only for 1 to 5 days, after which metabolic activity also ceased. The potential for adaptation to LAS exposure was investigated with Nitrosomonas europaea grown at a sublethal LAS level (10 mg liter⁻¹); compared to control cells, preexposed cells showed severely affected cell functions (cessation of growth, loss of viability, and reduced NH₄⁺ oxidation activity), demonstrating that long-term incubation at sublethal LAS levels was also detrimental. Our data strongly suggest that AOB are more sensitive to LAS than most heterotrophic bacteria are, and we hypothesize that thermodynamic constraints make AOB more susceptible to surfactant-induced stress than heterotrophic bacteria are. We further suggest that AOB may comprise a sensitive indicator group which can be used to determine the impact of LAS on microbial communities.     

Inhibition of the anaerobic digestion process by linear alkylbenzene sulfonates

Linear Alkylbenzene Sulfonates (LAS) are the most widely used synthetic anionicsurfactants. They are anthropogenic, toxic compounds and are found in the primarysludge generated in municipal wastewater treatment plants. Primary sludge is usuallystabilized anaerobically and therefore it is important to investigate the effect of thesexenobiotic compounds on an anaerobic environment. The inhibitory effect of LinearAlkylbenzene Sulfonates (LAS) on the acetogenic and methanogenic step of theanaerobic digestion process was studied. LAS inhibit both acetogenesis from propionate and methanogenesis from acetate and hydrogen and it is shown that the propionate-utilising bacteria are more sensitive to the presence of LAS than the acetoclastic methanogens. It has been proven that the inhibition intensity depends on the solids concentration and thus the term ``biomass specific LAS concentration' has been introduced in order to describe the phenomenon better. Conclusively, it is believed that the inhibitory effect of LAS is the main reason that anaerobic microbial enrichments on LAS have not been succeeded yet. Also, the inhibition caused by LAS on the acetogenic and methanogenic step of the anaerobic digestion process should be seriously taken into consideration when wastewater from a surfactant producing industry is to be treated biologically or enter a municipal wastewater treatment plant that employs anaerobic technology. The upper allowable biomass specific LAS concentration should be 14 mg LAS (gVSS)^-1.     

Fate of linear alkylbenzene sulfonates in the environment: A review

The fate and risk of linear alkylbenzene sulfonates (LAS) in various compartments of the environment have been reviewed. Under aerobic conditions LAS degrade rapidly and concentration of LAS has been found very low in effluents from aerobic sewage treatment plants (STP). On the contrary, in anaerobic STPs effluents, LAS concentrations have been found very high. Anaerobic effluents containing high LAS concentrations have been found to pose risk to aquatic environment. Similarly, LAS concentrations have been found high in anaerobically treated sewage sludge's. LAS enter the soil as a result of sludge application to the land. Risk to aquatic and terrestrial ecosystems is increased when wastewaters and sludge's are treated anaerobically.     

DNA microarray mediated transcriptional profiling of Nitrosomonas europaea in response to linear alkylbenzene sulfonates

Linear alkylbenzene sulfonates (LAS) constitute, quantitatively, the most important group of synthetic surfactants used today. We studied the gene expression of Nitrosomonas europaea in response to LAS using a DNA microarray because ammonia-oxidizers are thought to be more sensitive to LAS than other microorganisms. Our objective was to elucidate which genes are expressed for N. europaea in response to LAS exposure. Microarray analysis and real-time PCR assay revealed that c. 30 genes were significantly expressed after LAS exposure, in particular genes associated with energy production and conversion. Our findings demonstrate that physical disruption of membrane structures, which contain enzymes associated with energy production and conversion, might be an important explanation for the high sensitivity of N. europaea to LAS exposure.     

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.     

How adaptation and mass transfer control the biodegradation of linear alkylbenzene sulfonate by activated sludge

We use a nonsteady-state model to evaluate the effects of community adaptation and sorption kinetics on the fate of linear alkylbenzene sulfonate (LAS) in batch experiments conducted with activated sludge that was continuously fed different concentrations of LAS. We observed a sharp decrease in the biodegradation rate between 30 and 60 minutes and the presence of an LAS residual at the end of the batch experiments. The modeling analysis indicates that these phenomena were caused by relatively slow inter-phase mass transport of LAS. The modeling analyses also showed that the amount of LAS-degrading biomass increased when the continuous activated sludge was fed a higher LAS concentration. Although community adaptation to LAS involved accumulation of more LAS degraders, the increase was not proportional to the feed concentration of LAS, which supports the concept that LAS degraders also utilized portions of the general biochemical oxygen demand (BOD) fed to the continuous activated sludge systems.     

气单胞菌（Aeromonas sp．D-4）降解LAS的研究

Aeromonas sp.D-4不能以LAS作为唯一碳源,它对LAS的利用是通过共代谢来完成的。LAS对D-4具有毒害作用,而且,起始LAS浓度越高,毒害作用越大。LAS的最大去除串与起始LAS浓度呈负相关。当起始LAS在40-120mg/L之间时,去除串较高;如果起始LAS在40mg／L左右,则去除率可达s096以上。研究还表明,Aeromonas sp.D-4纯培养对LAS的去除率(最大值84．97%)大于混合菌(最大值78．57%)。耗氧呼吸测定证实了Aeromonas sp.D-4对于LAS的共代谢和LAS对细菌的毒性,同时也证实了培养基中LAS的消失是细菌作用的结果。     

阴离子表面活性剂LAS对产毒和无毒微囊藻生长及产毒特性的影响

文章研究了低浓度范围内不同浓度梯度的阴离子表面活性剂直链烷基苯磺酸盐(LAS)对产毒微囊藻(Microcystis aeruginosa, FACHB905)和无毒微囊藻(Microcystis wesenbergii, FACHB908)生长、光合特性、种间竞争及毒素合成的影响。结果表明,在0.05—5.0 mg/L LAS浓度梯度处理下,产毒微囊藻的生物量、产毒基因mcyD表达量和每细胞MCs含量均在培养12d后显著增加。产毒微囊藻胞内和胞外MCs含量在各LAS浓度处理后分别为0.069、0.052、0.061、0.038和0.037 fg/fg Chl.a及107.1、103.7、127.1、99.6和113.7 ng/L。即使在0.5 mg/L低浓度LAS处理条件下,上述3个参数也分别比对照组显著增加了24.2%、12.4倍和10.4%。浓度为0—0.2 mg/L LAS对无毒微囊藻的生物量无明显影响,而较高浓度的LAS(0.5—5.0 mg/L)明显抑制了无毒微囊藻的生长。在两株微囊藻混合培养时, 0.2—1.0 mg/L LAS处理组的产毒铜绿微囊藻mcy D的表达对LAS...     

Screening test for assessment of ultimate biodegradability: linear alkylbenzene sulfonates.

A relatively simple shake-flask system for determining CO2 evolution was developed to assess the ultimate biodegradability by soil and sewage micro-organisms of chemicals which enter the environment. Linear alkylbenzene sulfonates (LAS) were used as model compounds to evaluate the method and were found to undergo substantial biodegradation in this dilute system. At the 30 mg/liter test concentration, higher-molecular-weight LAS compounds were biodegraded at a slower rate and to a lesser extent than lower-molecular-weight LAS, an effect which was eliminated or greatly reduced upon incremental addition of the LAS to the test medium during the first week of incubation. LA35S was used to demonstrate rapid LAS desulfonation, and 14CO2 evolution studies with (14C) benzene ring-labeled LAS indicated concomitant biodegradation of the entire LAS molecule as well as the LAS aromatic component. The test can be employed to examine numerous compounds at the same time and is readily adapted to studies of the effect of variation in temperature and oxygen concentration on biodegradation.     

Acute toxicity of anionic surfactants sodium dodecyl sulphate (SDS) and linear alkylbenzene sulphonate (LAS) on the fertilizing capability of gilthead (Sparus aurata L.) sperm

In the present work we have evaluated and compared the acute toxicity of two anionic surfactants, Sodium Dodecyl Sulphate (SDS) and Linear Alkylbenzene Sulphonate (LAS) on the fertilizing capability of gilthead Sparus aurata L. sperm. The criterion used to judge exposure effectiveness was fertilization success. Spawned eggs and sperms were collected from adult giltheads. Sperms were dosed separately with different concentrations of SDS and LAS for 60 minutes. After this period, sperms and eggs were combined for 20 minutes during which fertilization took place. Finally, the number of fertilized eggs were counted and recorded to estimate the percentage of fertilization. Exposure to SDS and LAS concentrations of 0.3, 0.6, 1.5, 3 and 6 mg/L for 60 minutes caused a significant inhibitory effect on fertilization success in gilthead Sparus aurata L.. In addition, the EC50 value for gilthead fertilization after sperm exposure was found to be 2.8 mg/L and in the case of LAS it was of 2.6 mg/L. The comparison of the results from SDS and LAS shows that the latter has a stronger negative effect on sperm viability than SDS.