Biodegradation of linear alkylbenzene sulfonates in sulfate-leached soil mesocosms (original) (raw)
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Biodegradation Of Linear Alkyl Benzene Sulfonate By Bacterial Consortium
2006
Surface active agents (surfactants) are chemical compounds which are massively used as raw material in detergent production. Synthetic type surfactants are often used because they perform better and are more economical compared to natural detergents. Linear Alkyl Benzene Sulfonate (LAS) is one of the synthetic surfactants that is widely used. Although LAS is biodegradable, its introduction to the environment in big amounts harms water bodies. Research on biodegradation of LAS with 100 ppm, 400 ppm, 700 ppm, 1000 ppm and 1500 ppm concentrations was conducted by using consortium of bacteria comprising of Pseudomonas aeroginosa, Bacillus subtilis, Bacillus aglomerans, Bacillus cereus, Bacillus alvae. Experiments were carried out for twelve days, at 29oC with initial total inoculum of bacteria at 1,59 x 108 CFU/mL. Results showed that this type of bacterial consortium could tolerate 1500 ppm in LAS environment. However, significant growth rate did not occurr, 0.039 – 0.042 hour -1 and...
1 Biodegradation of Linear Alkyl Benzene Sulfonate by Bacterial Consortium
2015
Surface active agents (surfactants) are chemical compounds which are massively used as raw material in detergent production. Synthetic type surfactants are often used because they perform better and more economical compared to natural detergents. Linear Alkyl Benzene Sulfonate (LAS) is one of synthetic surfactants that is widely used. Although LAS is biodegradable, its introduction to the environment in big amount harms the water bodies. Research on biodegradation of LAS with 100 ppm, 400 ppm, 700 ppm, 1000 ppm and 1500 ppm concentrations was conducted by using consortium of bacteria comprises of Pseudomonas aeroginosa, Bacillus subtilis, Bacillus aglomerans, Bacillus cereus, Bacillus alvae. Experiments were carried out in twelve days, in 29oC temperature with initial total inoculum bacteria 1,59 x 108 CFU/mL. Results showed that this type of bacterial consortium could live until 1500 ppm in LAS environment. However, significant growth rate did not occurr, 0.039 – 0.042 hour-1 and n...
Anionic surfactants, the earliest and the most common surfactants in detergent and cosmetic product formulations contribute significantly to the pollution profile of the ecosystem. Linear alkylbenzene sulfonates (LAS), a major chemical constituent of detergents, forms an imperative group of anionic surfactants. Bioremediation of LAS by conventional processes such as activated sludge is ineffective due to the low kinetics of degradation by unsuitable organisms and foam production. Hence this study was focused on isolating and characterizing indigenous LASdegrading bacteria from soil. Twenty different LASdegrading bacteria were isolated from detergentcontaminated soil by enrichment culture technique and degradation efficiency was assessed by Methylene Blue Active Substances (MBAS) assay and by reverse-phase high-performance liquid chromatography (HPLC) analysis. The most efficient LASdegrading isolates, L9 (81.33±0.7) and L12 (81.81± 0.8), were selected and identified as Pseudomonas nitroreducens (MTCC 10463) and Pseudomonas aeruginosa (MTCC 10462). The 16S rDNA sequences of the isolates were deposited in NCBI GenBank under the accession numbers HQ 271083 (L9) and HQ 271084 (L12). The isolates were capable of degrading 0.05 g/l LAS at 25 °C and pH 7.0–7.5. Presence of a solid support caused biofilm formation which in turn enhanced LAS degradation. The isolates tend to display diauxic growth with alternate carbon source such as dextrose. These isolates also have the capability to degrade other xenobiotics like hydrocarbons and pesticides. Since xenobiotic pollutants in nature occur as a mixture of compounds rather than single pollutants, the potential of these two indigenous LAS-degrading isolates to degrade multiple xenobiotics gains relevance. Keywords Biodegradation . Methylene Blue Active
Journal of Xenobiotics, 2011
Aerobic biodegradation of linear alkylbenzene sulfonate (LAS) by LAS-utilizing bacteria (LUB) in the presence of other sources of carbon (glucose and soluble starch) was examined. Biodegradation of LAS was monitored as primary degradation in terms of half-life (t½) of the surfactant. Biodegradation of LAS by the individual LUB was slower in the presence of Glucose. Biodegradation of the surfactant by the various consortia of LUB was slower in the presence of the carbon sources: t½ increased to 3 days. The rates of biodegradation by the consortia can be ranked as: four-membered (t½=9 days) > three-membered (t½=9 to 13 days) > two-membered consortia (t½=10 to 15 days). Generally, degradation in the presence of the carbon sources was faster with the consortia than the individual species. Degradation of the surfactant by the LUB was generally fastest in the absence of additional carbon sources. The possible role of additional carbon sources in pe...
Biodegradation of Linear Alkylbenzene Sulfonates and Their Degradation Intermediates in Seawater
Environmental Science & Technology, 2004
A bacterial consortium capable of degrading the linear alkylbenzene sulfonate (LAS) was isolated from the wastewater treatment plant. The bacterial consortium consisted of two members, Pantoea agglomerans and Serratia odorifera 2. Cells were grown evenly together in a minimal medium (M9) and nutrient broth (NB). The bacterial consortium was able to grow in the minimal medium containing LAS as the only carbon source. The percentage degradation of 200 ppm LAS by this bacterial consortium was better when cells were grown in NB (∼70%) than in the M9 medium (36%). Also, the degradation ability by the bacterial consortium was very much higher than by its individual cells. This work shows that the two bacteria complement each other in the degrading ability of LAS, indicating catabolic cooperation between the two consortium members. An incubation temperature of 32 • C, an agitation rate of 250 rev min −1 , and the addition of different carbon and nitrogen sources all independently caused complete mineralization of 200 mg L −1 LAS within 48-72 h.
Journal of Xenobiotics, 2012
Untreated detergent bearing wastes discharged into the environment are sources of linear alkylbenzene sulfonate (LAS). Detergent wastes usually do not contain nitrogen or contain very low amounts. Biostimulation by introducing limiting nutrient element can be useful in biotreatment of such waste. The effect of inorganic and organic nitrogen supplements on aerobic degradation of LAS by LAS-utilizing bacteria was examined. Phosphate-buffered LAS mineral media were prepared and supplemented with different nitrogen sources: NPK fertilizer (inorganic) and urea fertilizer (organic). Individual and various consortia of pure cultures of Alcaligenes odorans, Citrobacter diversus, Micrococcus luteus and Pseudomonas putida, previously isolated from a detergent effluent polluted stream, were used. Biodegradation of LAS was monitored in terms of half-life (t ½) of the surfactant. The rates of biodegradation by the consortia can be ranked as: 4-membered (t ½ =8-12 days) >3-membered (t ½ =8-13 days) >2-membered consortia (t ½ =10-15 days) >individuals (t ½ =9-16 days). The inorganic nitrogen source enhanced utilization of the surfactant, while organic nitrogen supplementation generally slowed degradation of the surfactant. In undertaking biotreatment of detergent bearing effluent, inorganic nitrogen should be used as biostimulant.
Anaerobic Degradation of Linear Alkylbenzene Sulfonates in Coastal Marine Sediments
Environmental Science & Technology, 2007
This research shows for the first time the degradation of linear alkylbenzene sulfonates (LAS) under anaerobic conditions, together with the presence of metabolites and the identification of microorganisms involved in this process. This compound is the most widely used surfactant and its main environmental concern is related to its persistence in the absence of oxygen as LAS accumulates in anaerobic sediments and sewage sludges. Laboratory experiments performed with anoxic marine sediments spiked with 10-50 ppm of LAS demonstrated, however, that its degradation reached 79% in 165 days via the generation of sulfophenyl carboxylic acids (SPCs). Almost all of the added LAS (>99%) was found to be attached to the sediment while the less hydrophobic SPCs were predominant in solution, as their concentration increased progressively up to 3 ppm during the full course of the experiment. Average half-life for LAS has been estimated to be 90 days, although higher values should be expected when the LAS concentration exceeds 20 ppm, due to inhibition of the microbial community. Sulfate-reducing and methanogenic activities proved to be intense during the experiment. Several sulfate-reducing bacteria and firmicutes/clostridia have been identified as possible candidates for effecting this degradation. Our results imply that the persistence of LAS in anoxic compartments, such as marine sediments, should be reconsidered when evaluating its environmental risk.
Biodegradation of Coproducts of Commercial Linear Alkylbenzene Sulfonate
Environmental Science & Technology, 1997
Dialkyltetralin sulfonate (DATS) and single methyl-branched isomers of linear alkylbenzene sulfonate (iso-LAS) are coproducts that together can range from 1 to 10% of commercial LAS depending on the manufacturing process. Biodegradation studies using radiolabeled DATS and iso-LAS showed mineralization by indigenous microbial populations in laboratory simulations of aquatic and soil environments. Half-lives ranged from 2 to 20 days, which is rapid enough to suggest that accumulation would not occur in these environments. Upon exposure to laboratory activated sludge treatment, most model iso-LAS compounds showed greater than 98% parent compound removal, extensive mineralization (>50%), and 79-90% ultimate biodegradation (mineralization plus conversion to biomass). Activated sludge treatment of DATS and one of the iso-LAS isomers (methyl group attached to the benzylic carbon of the alkyl chain) resulted in >98% removal, 3-12% ultimate biodegradation and apparent formation of carboxylated biodegradation intermediates that accounted for 88-97% of the original material. These DATS and iso-LAS biodegradation intermediates continued to mineralize in simulated receiving water and soil environments at rates similar to that of sulfophenyl carboxylate (SPC) intermediates of a standard LAS.
Water Research, 2001
Abstract}The effect of wet air oxidation on the aerobic biodegradability of a model wastewater containing 1000 mg L À1 of linear alkylbenzene sulfonate (LAS) has been investigated. Semibatch oxidation experiments were performed at a temperature of 473 K, an oxygen partial pressure of 1.3 MPa and residence times varying from 40 to 390 min, while continuous oxidation experiments were performed at a residence time of 120 min. Oxygen uptake tests were performed to assess the aerobic biodegradability of both the oxidised and the original LAS solutions using cultures that had been adapted to both LAS and oxidation intermediates. The concentration of total organic carbon, chemical oxygen demand and active detergent were followed throughout the wet oxidation and biodegradation experiments, while the main intermediates formed during wet oxidation were identified by means of Electrospray-MS and high performance liquid chromatography. It was found that LAS could be easily oxidised at 473 K to yield a group of molecules with short alkyl chains which do not behave as active detergents. Sulfonated aromatics are produced as intermediates which have had the alkyl chain shortened. The segments of alkyl chains broken off the intermediate compounds appear primarily as short chain organic acids. The original, unoxidised 1000 mg L À1 LAS solution was found to be readily biodegradable in the laboratory aerobic reactors operating at low organic loadings and substrate to microorganism concentration ratios. However, wet oxidation resulted in effluents that were less readily biodegradable than the original LAS with biodegradability decreasing with increasing degree of oxidation. These results suggest that, at the conditions under consideration, a combined chemical pre-oxidation and biological post-treatment process may be less effective in removing LAS than a single-stage biological or chemical process. #