Characterization of the biosorption of fast black azo dye K salt by the bacterium Rhodopseudomonas palustris 51ATA strain

BACKGROUND: Removal of dyes from wastewater by microorganisms through adsorption, degradation, or accumulation has been investigated. Biological methods used for dye treatment are generally always effective and environmentally friendly. In this study, biosorption of the Fast Black K salt azo dye by the bacterium Rhodopseudomonas palustris 51ATA was studied spectrophotometrically, at various pH (2­10), temperatures (25°C, 35°C, and 45°C) and dye concentrations (25­400 mg L-1). RESULTS: The bacterial strain showed extremely good dye-removing potential at various dye concentrations. IR studies at different temperatures showed that the dye was adsorbed on the bacterial surface at lower temperatures. Characteristics of the adsorption process were investigated by Scatchard analysis at 25°C and 35°C. Scatchard analysis of the equilibrium binding data for the dye on this bacterium gave rise to linear plots, indicating that the Langmuir model could be applied. The regression coefficients obtained for the dye from the Freundlich and Langmuir models were significant and divergence from the Scatchard plot was observed. CONCLUSION: The adsorption behavior of the dye on this bacterium was expressed by the Langmuir, Freundlich, and Temkin isotherms. The adsorption data with respect to various temperatures provided an excellent fit to the Freundlich isotherm. However, when the Langmuir and Temkin isotherm models were applied to these data, a good fit was only obtained for the dye at lower temperatures, thus indicating that the biosorption ability of R. palustris 51ATA is dependent on temperature, pH, and dye concentration.

Structural-functional analyses of textile dye degrading azoreductase, laccase and peroxidase: a comparative in silico study

Background: Textile industry not only plays a vital role in our daily life but also a prominent factor in improving global economy. One of the environmental concern is it releases huge quantities of toxic dyes in the water leading to severe environmental pollution. Bacterial laccase and azoreductase successfully oxidize complex chemical structure of nitrogen group-containing azo dyes. Additionally, the presence of textile dye infuriates bacterial peroxidase to act as a dye degrading enzyme. Our present study deals with three textile dye degrading enzymes laccase, azoreductase, and peroxidase through analyzing their structural and functional properties using standard computational tools. Result: According to the comparative analysis of physicochemical characteristics, it was clear that laccase was mostly made up of basic amino acids whereas azoreductase and peroxidase both comprised of acidic amino acids. Higher aliphatic index ascertained the thermostability of all these three enzymes. Negative GRAVY value of the enzymes confirmed better water interaction of the enzymes. Instability index depicted that compared to laccase and preoxidase, azoreductase was more stable in nature. It was also observed that the three model proteins had more than 90% of total amino acids in the favored region of Ramachandran plot. Functional analysis revealed laccase as multicopper oxidase type enzyme and azoreductase as FMN dependent enzyme, while peroxidase consisted of α-ß barrel with additional haem group. Conclusion: Present study aims to provide knowledge on industrial dye degrading enzymes, choosing the suitable enzyme for industrial set up and to help in understanding the experimental laboratory requirements as well.

Efficiency of decolorization of different dyes using fungal biomass immobilized on different solid supports

Abstract Different technologies may be used for decolorization of wastewater containing dyes. Among them, biological processes are the most promising because they seem to be environmentally safe. The aim of this study was to determine the efficiency of decolorization of two dyes belonging to different classes (azo and triphenylmethane dyes) by immobilized biomass of strains of fungi (Pleurotus ostreatus - BWPH, Gleophyllum odoratum - DCa and Polyporus picipes - RWP17). Different solid supports were tested for biomass immobilization. The best growth of fungal strains was observed on the washer, brush, grid and sawdust supports. Based on the results of dye adsorption, the brush and the washer were selected for further study. These solid supports adsorbed dyes at a negligible level, while the sawdust adsorbed 82.5% of brilliant green and 19.1% of Evans blue. Immobilization of biomass improved dye removal. Almost complete decolorization of diazo dye Evans blue was reached after 24 h in samples of all strains immobilized on the washer. The process was slower when the brush was used for biomass immobilization. Comparable results were reached for brilliant green in samples with biomass of strains BWPH and RWP17. High decolorization effectiveness was reached in samples with dead fungal biomass. Intensive removal of the dyes by biomass immobilized on the washer corresponded to a significant decrease in phytotoxicity and a slight decrease in zootoxicity of the dye solutions. The best decolorization results as well as reduction in toxicity were observed for the strain P. picipes (RWP17).

Decolorization of azo dyes (Direct Blue 151 and Direct Red 31) by moderately alkaliphilic bacterial consortium

Abstract Removal of synthetic dyes is one of the main challenges before releasing the wastes discharged by textile industries. Biodegradation of azo dyes by alkaliphilic bacterial consortium is one of the environmental-friendly methods used for the removal of dyes from textile effluents. Hence, this study presents isolation of a bacterial consortium from soil samples of saline environment and its use for the decolorization of azo dyes, Direct Blue 151 (DB 151) and Direct Red 31 (DR 31). The decolorization of azo dyes was studied at various concentrations (100–300 mg/L). The bacterial consortium, when subjected to an application of 200 mg/L of the dyes, decolorized DB 151 and DR 31 by 97.57% and 95.25% respectively, within 5 days. The growth of the bacterial consortium was optimized with pH, temperature, and carbon and nitrogen sources; and decolorization of azo dyes was analyzed. In this study, the decolorization efficiency of mixed dyes was improved with yeast extract and sucrose, which were used as nitrogen and carbon sources, respectively. Such an alkaliphilic bacterial consortium can be used in the removal of azo dyes from contaminated saline environment.

Microbial dynamics during azo dye degradation in a UASB reactor supplied with yeast extract

The present work aimed to investigate the microbial dynamics during the anaerobic treatment of the azo dye blue HRFL in bench scale upflow anaerobic sludge bed (UASB) reactor operated at ambient temperature. Sludge samples were collected under distinct operational phases, when the reactor were stable (low variation of color removal), to assess the effect of glucose and yeast extract as source of carbon and redox mediators, respectively. Reactors performance was evaluated based on COD (chemical oxygen demand) and color removal. The microbial dynamics were investigated by PCR-DGGE (Polimerase Chain Reaction - Denaturing Gradient of Gel Electrophoresis) technique by comparing the 16S rDNA profiles among samples. The results suggest that the composition of microorganisms changed from the beginning to the end of the reactor operation, probably in response to the presence of azo dye and/or its degradation byproducts. Despite the highest efficiency of color removal was observed in the presence of 500 mg/L of yeast extract (up to 93%), there were no differences regarding the microbial profiles that could indicate a microbial selection by the yeast extract addition. On the other hand Methosarcina barkeri was detected only in the end of operation when the best efficiencies on color removal occurred. Nevertheless the biomass selection observed in the last stages of UASB operation is probably a result of the washout of the sludge in response of accumulation of aromatic amines which led to tolerant and very active biomass that contributed to high efficiencies on color removal.

Identificación de colágeno I y III con picrosirius red/ polarización en el estroma de tumores salivales / Identification of type I and III collagen by picrosirius red/polarization of tumoral salivary stroma

El estroma juega un rol importante en los procesos tumorales de invasión y metástasis. Las fibras de colágeno tipo I son el principal componente estructural del estroma en distintos tumores. Sin embargo, hay muy pocos estudios en los tumores de glándulas salivales. Basándonos en estos antecedentes el objetivo de la presente comunicación fue estudiar las características del colágeno con Picrosirius red/polarización en tumores benignos y malignos de glándulas salivales para evaluar su posible rol en los mecanismos de progresión tumoral. Cortes histológicos de adenoma pleomórfico, carcinoma adenoide quístico y carcinoma epitelial mioepitelial se colorearon con H/E y Picrosirius red y se examinaron con microscopio de polarización. La birrefringencia del colágeno con Picrosirius/polarización resultó diferente en el estroma de los tumores malignos (carcinoma adenoide quístico y carcinoma epitelial mioepitelial), con predominio de colágeno I, en comparación con el tumor benigno (adenoma pleomórfico), con predominio de colágeno III. El diferente perfil de coloración en las fibras colágenas producidas en el estroma de los tumores analizados podría relacionarse con diferentes mecanismos de expansión tumoral, los que fueron poco estudiados en los tumores de glándulas salivales. Más estudios son necesarios para obtener resultados más concluyentes que contribuyan al diagnóstico, pronóstico y tratamiento.

The stroma plays an important rol in tumoral invasion and metastasis. Type I collagen is the main structural component of the stroma in several tumors. However, there are few studies on salivary gland tumors. Based on this background the objective of the present communication was to study collagen characteristics with picrosirius red/polarization on malignant and benign tumors of salivary glands to evaluate its posible rol in the tumoral progression mechanism. Histological sections of pleomorphic adenoma, adenoid cystic carcinoma and epithelial/myoepithelial carcinoma were stained with H/E and picrosirius red and were studied with polarization microscope. Collagen birefringence with Picrosirius/polarization was different in the malignant tumor stroma (adenoid cystic carcinoma and epithelialmyoepithelial carcinoma), with predominance of type I collagen, compared with a benign tumor (pleomorphic adenoma), with predominance of type III collagen. The different staining profile in collagen fibers produced in the benign and malignant stroma tumors analized could be related with different tumoral expansion mechanism, which were scarce studied on the salivary glands tumors. More studies are needed to obtain more conclusive results to contribute to diagnosis, prognosis and treatment.

Decolorization of different azo dyes by Phanerochaete chrysosporium RP78 under optimal condition

Detoxification of synthetic dyes is one of the main challenges in clearing textile industry wastes. Biodegradation of azo-dyes using Phanerochaete chrysosporium is one the most environmentally friendly methods available. The main enzymes responsible for mycodecolorization process are lignin and manganese peroxidases. Here, optimization of expression conditions has been carried out with manipulating culture condition and nutrient sources. Therefore, the effects of buffer and temperature as well as nitrogen source on lignin peroxidase and manganese peroxidase production were investigated at two levels and four levels, respectively. For this purpose, P. chrysosporium RP78 based on Taguchi design of experiment has been applied. Maximum lignin and manganese peroxidase activities of 182 +/- 2.5 U/L and 850 +/- 41 U/L were obtained under predicted optimum conditions, respectively. Thereby, about 100% decolorization was achieved after 24 h for two most widely used groups of azo dyes in textile industry consisting reactive and acidic. The physical adsorption of the azo dyes by mycelia was not significant which indicated that the enzymatic degradation of the dyes was occurred. Time profile of these enzymes showed that manganese peroxidase was peaked on 9 th day while lignin peroxidase peaked on 13 th. day and remained stable in the culture. The extracellular expression profiles of both were studied by 2 dimensional gel electrophoresis to partially characterize the enzymes

Does acute promyelocytic leukemia in Indian patients have biology different from the West?

Acute promyelocytic leukemia (APML) is a well-characterized malignancy with typical clinico-hematological and molecular features. However, Indian data on this malignancy are limited. This study was conducted to determine the clinico-hematological profile of APML in India. Thirty-five patients with APML presenting to Hematology Department, AIIMS, New Delhi, between July 2003 and June 2005 were evaluated for presenting clinical features, hemogram, peripheral smear, bone marrow morphology and cytochemistry. Reverse transcriptase PCR (RT-PCR) for PML-RARalpha was done in all cases. Male-to-female ratio was 0.9:1 (males--17 and females--18) with median age 25 years (range 11-57 years). Presenting features included anemia, bleeding, fever, gum hypertrophy and scrotal ulceration. All cases showed hypergranular abnormal promyelocytes. Median hemoglobin was 6.3 g/dL (range - 3.0-9.0 g/dL), total leukocyte count (TLC) was 33.88 x 10(9) /L (range - 1-170 x 10(9) /L). Platelet count was 28 x 10(9) /L (range - 4-170 x 10(9) /L). All cases were positive for myeloperoxidase and sudan black (SB), whereas 60% cases also showed non specific esterase (NSE) positivity with 40% cases being fluoride sensitive. RT-PCR showed PML-RARalpha in 33/35 cases with the bcr3 isoform being present in 24/33 positive cases (72.7%). The two cases negative for PML-RARalpha showed typical morphology and responded to ATRA. On statistical analysis, no correlation was found between bcr isoform and TLC, platelet count, age sex and early death. Unusual features included gum hypertrophy and scrotal ulceration at presentation and high median presenting TLC (33.8 x 10(9) /L). There was, however, no microgranular variant. Another interesting feature was a high incidence of NSE positivity (60%), which was fluoride sensitive in 40%. Moreover, the bcr3 isoform was significantly overexpressed (72.7%) in comparison to other studies. APML in India has certain unusual features, which may reflect a different biology.

Decolorization of remazol yellow RR gran by white rot fungus Phanerochaete chrysosporium.

In this study, the removal of color, chemical oxygen demand (COD) and aromatic group from one of the azo dyes, Remazol Yellow RR Gran, had been carried out by using one of the white rot fungi, Phanerochaete chrysosporium. Experimental studies were performed in growth media containing different amounts of dye and glucose. Color measurements were done at 436nm wavelength using spectrophotometer while aromatic group measurements were done at 280 nm wavelength using UV/Visible spectrophotometer. As a result of this study the values of the removable color concentration were determined as 10 mgl(-1) and lower. The optimum medium glucose concentration was determined to be 2 gl(-1) during color removal processes, aromatic group measurements were done in samples in the UV region at 280 nm wavelength. As a result of the measurements, it was shown that certain amount of aromatic group remained in the model wastewater at the end of the process.

Simple scheme for identification of common species of enterobacteriaceae.

We propose a simple scheme for the identification of enterobacteriaceae species which routinely necessitates numerous biochemical tests and prolonged time span. In the scheme, family enterobacteriaceae is initially divided into four major groups depending on two important biochemical reactions viz. Lactose fermentation (L) and Methyl red test (MR). Each of the four groups, Group I (L + MR+), Group II (L + MR-), Group III (L- MR-), Group IV (L- MR+) can further be differentiated by using few tests. Eleven genera and 23 species can be identified by this scheme using limited biochemical tests. As many as 990 strains of enterobacteriaceae were subjected to standard biochemical tests and proposed simple scheme for identification. The discrepancy was observed only with 8 atypical strains of E. coli.

Toxicity assessment and microbial degradation of azo dyes.

Toxic effluents containing azo dyes are discharged from various industries and they adversely affect water resources, soil fertility, aquatic organisms and ecosystem integrity. They pose toxicity (lethal effect, genotoxicity, mutagenicity and carcinogenicity) to aquatic organisms (fish, algae, bacteria, etc.) as well as animals. They are not readily degradable under natural conditions and are typically not removed from waste water by conventional waste water treatment systems. Benzidine based dyes have long been recognized as a human urinary bladder carcinogen and tumorigenic in a variety of laboratory animals. Several microorganisms have been found to decolourize, transform and even to completely mineralize azo dyes. A mixed culture of two Pseudomonas strains efficiently degraded mixture of 3-chlorobenzoate (3-CBA) and phenol/cresols. Azoreductases of different microorganisms are useful for the development of biodegradation systems as they catalyze reductive cleavage of azo groups (-N=N-) under mild conditions. In this review, toxic impacts of dyeing factory effluents on plants, fishes, and environment, and plausible bioremediation strategies for removal of azo dyes have been discussed.

Comparative azo reductase activity of red azo dyes through caecal and hepatic microsomal fraction in rats.

In order to study the rate of formation of toxic aromatic amines, anaerobic reduction of four red azo dyes viz. amaranth, carmoisine, fast Red E and ponceau 4R was investigated by incubating caecal content and hepatic microsomal fraction of rats with 37.5 microM concentration of dyes in sodium phosphate buffer pH 7.4 using NADPH generating system, glucose oxidase system and nitrogen as the gaseous phase. Caecal suspension exhibited higher azo reductase activity than that of hepatic microsomal fraction using any of the 4 azo dyes. Caecal microbes showed maximal azo reductase activity when ponceau 4R was used as a substrate followed by fast Red E and carmoisine, while with amaranth the activity was minimum. Similarly ponceau 4 R exhibited maximum hepatic microsomal azo reductase activity followed by fast Red E and carmoisine whereas, amaranth had minimum activity. Caecal flora possessed almost 17 fold higher degradative capability of ponceau 4 R and fast Red E colourants than the hepatic microsomal fraction. The higher reductive ability through caecal flora for ponceau 4R and fast Red E signifies the formation of more aromatic amines which may be re-absorbed through the intestine to be either eliminated through urine as conjugates or retained in the target tissues to elicit toxic effects.

Bio-metabolic disposition of metanil yellow, orange II and their blend by caecal microflora of rats.

Caecal microflora were employed to study the degradation pattern, with time course of Metanil yellow and Orange II-two extensively used non-permitted food colours. Metanil yellow and Orange II showed the respective Degradation Index 50 (DI 50) values of 369 and 288 min. However, the blend of Metanil yellow and Orange II (1:1) resulted in the D1 50.value of 288 min. Metanil yellow, Orange II and their blend were resolved into respective metabolites in different solvent systems.