Removal of Triphenylmethane Dyes by Bacterial Consortium

A new consortium of four bacterial isolates (Agrobacterium radiobacter; Bacillus spp.; Sphingomonas paucimobilis, and Aeromonas hydrophila)-(CM-4) was used to degrade and to decolorize triphenylmethane dyes. All bacteria were isolated from activated sludge extracted from a wastewater treatment station of a dyeing industry plant. Individual bacterial isolates exhibited a remarkable color-removal capability against crystal violet (50 mg/L) and malachite green (50 mg/L) dyes within 24 h. Interestingly, the microbial consortium CM-4 shows a high decolorizing percentage for crystal violet and malachite green, respectively, 91% and 99% within 2 h. The rate of chemical oxygen demand (COD) removal increases after 24 h, reaching 61.5% and 84.2% for crystal violet and malachite green, respectively. UV-Visible absorption spectra, FTIR analysis and the inspection of bacterial cells growth indicated that color removal by the CM-4 was due to biodegradation. Evaluation of mutagenicity by using Salmonella typhimurium test strains, TA98 and TA100 studies revealed that the degradation of crystal violet and malachite green by CM-4 did not lead to mutagenic products. Altogether, these results demonstrated the usefulness of the bacterial consortium in the treatment of the textile dyes

The cientificWorldJOURNAL Research Article Removal of Triphenylmethane Dyes by Bacterial Consortium

A new consortium of four bacterial isolates (Agrobacterium radiobacter; Bacillus spp.; Sphingomonas paucimobilis, and Aeromonas hydrophila)-(CM-4) was used to degrade and to decolorize triphenylmethane dyes. All bacteria were isolated from activated sludge extracted from a wastewater treatment station of a dyeing industry plant. Individual bacterial isolates exhibited a remarkable colorremoval capability against crystal violet (50 mg/L) and malachite green (50 mg/L) dyes within 24 h. Interestingly, the microbial consortium CM-4 shows a high decolorizing percentage for crystal violet and malachite green, respectively, 91% and 99% within 2 h. The rate of chemical oxygen demand (COD) removal increases after 24 h, reaching 61.5% and 84.2% for crystal violet and malachite green, respectively. UV-Visible absorption spectra, FTIR analysis and the inspection of bacterial cells growth indicated that color removal by the CM-4 was due to biodegradation. Evaluation of mutagenicity by using Salmonella typhimurium test strains, TA98 and TA100 studies revealed that the degradation of crystal violet and malachite green by CM-4 did not lead to mutagenic products. Altogether, these results demonstrated the usefulness of the bacterial consortium in the treatment of the textile dyes

Population Structure of Pseudomonas aeruginosa from Five Mediterranean Countries: Evidence for Frequent Recombination and Epidemic Occurrence of CC235

Several studies in recent years have provided evidence that Pseudomonas aeruginosa has a non-clonal population structure punctuated by highly successful epidemic clones or clonal complexes. The role of recombination in the diversification of P. aeruginosa clones has been suggested, but not yet demonstrated using multi-locus sequence typing (MLST). Isolates of P. aeruginosa from five Mediterranean countries (n = 141) were subjected to pulsed-field gel electrophoresis (PFGE), serotyping and PCR targeting the virulence genes exoS and exoU. The occurrence of multi-resistance (≥3 antipseudomonal drugs) was analyzed with disk diffusion according to EUCAST. MLST was performed on a subset of strains (n = 110) most of them had a distinct PFGE variant. MLST data were analyzed with Bionumerics 6.0, using minimal spanning tree (MST) as well as eBURST. Measurement of clonality was assessed by the standardized index of association (IAS). Evidence of recombination was estimated by ClonalFrame as well as SplitsTree4.0. The MST analysis connected 70 sequence types, among which ST235 was by far the most common. ST235 was very frequently associated with the O11 serotype, and frequently displayed multi-resistance and the virulence genotype exoS−/exoU+. ClonalFrame linked several groups previously identified by eBURST and MST, and provided insight to the evolutionary events occurring in the population; the recombination/mutation ratio was found to be 8.4. A Neighbor-Net analysis based on the concatenated sequences revealed a complex network, providing evidence of frequent recombination. The index of association when all the strains were considered indicated a freely recombining population. P. aeruginosa isolates from the Mediterranean countries display an epidemic population structure, particularly dominated by ST235-O11, which has earlier also been coupled to the spread of ß-lactamases in many countries

Traitement biologique des eaux usées textiles – Étude de cas : Station d’épuration des eaux usées textiles

En Tunisie, plusieurs usines de textiles ont comme activité principale le lavage des jeans, caractérisée par un débit de charge de 50 L.kg-1 et COD de 94 g.kg-1. Le traitement de la pollution de l’environnement par des microorganismes est une technologie prometteuse. Cette étude contribuera à comprendre le fonctionnement des boues activées des eaux usées dans l’industrie textile. Pendant six mois, certains paramètres physico-chimiques sont telles que la surveillance de la demande chimique en oxygène (DCO), demande biologique en oxygène (DBO) et de la couleur avec le dénombrement des micro-organismes eucaryotes rotifères et bactériennes cultivables. Les souches bactériennes isolées ont été identifiées biochimiquement par Api 20NE. Nos résultats montrent un nombre élevé de rotifères prédateurs pour les bactéries dans les boues activées. Le rapport DBO/DCO calculé était faible (< 0,3). Le nombre élevé de rotifères est accompagné d’une faible valeur de DBO/DCO. Une forte concentration en bacterie (cfu) a été observée lorsque le nombre de rotifères baisse. Les souches bactériennes isolées à partir de boues activées ont été identifiées comme étant Pseudomonas vesicularis, Pseudomonas maltophilia, Pseudomonas stutzeri, Pseudomonas cepacia, Achromobacter SrVD, Aeromonas hydrophila et Sphingomonas paucimobilis

Traitement biologique des eaux résiduaires de papeterie par un consortium bactérien

Les rejets des usines de pâtes à papier ont une composition assez diverse et présentent une grande menace environnementale. L’épuration des eaux résiduaires alcalines de fabriques de pâte et papier pose, actuellement, un problème très ardu à résoudre. Un des aspects les plus intéressants de ce procédé, outre son prix de revient relativement bas, est la réduction très importante de la demande chimique en oxygène (DCO) de l’ordre de 90 %. La pertinence scientifique du papier : les eaux usées d’usines de papier ont été dégradées par Sphingomonas paucimobilis et les bactéries filamenteuses dans les sept jours à condition statique avec un rendement de 98 % dans l’abattement du DCO

Adhesive properties of environmental <i>Vibrio alginolyticus</i> strains to biotic and abiotic surfaces

The ability of Vibrio alginolyticus strains isolated from a bathing and fishing area (Khenis, Centre of Tunisia) to adhere to both biotic and abiotic surfaces was evaluated in the present work. The biochemical, physiological and enzymatic activities of all strains was also investigated. Three morphotypes of V. alginolyticus were obtained on Congo red agar and only 14 strains produced black colonies. The majority of strains were able to degrade the skin mucus of both Sparus aurata and Dicentrarchus labrax fishes while the fish mucus preparation of these two specimens exhibits a high level of anti-V. alginolyticus strains. Adhesive properties were observed in 37.5% of the analyzed V. alginolyticus strains to Hep-2 cells and 50% to Caco-2 cells. All strains were able to form a purple pellicule on glass tube when they were stained with Crystal violet. Fifteen percent of V. alginolyticus strains (16/32) were strongly adhesive to polystyrene with a values ranging from 3.04 to 18.25 at 595 nm and only four strains were weak biofilm forming. V. alginolyticus bacterium possess a strong adhesive power to both biotic and inertes surfaces. These proprieties may allow to these strains to persist in this biotope in planctonic state or attached to both biotic and abiotic surfaces