Abstract: Azo dyes are xenobiotic and recalcitrant against biodegradation, causing environmental problems. Under certain environmental conditions, microorganisms can transform dyes to non-coloured products or completely mineralize them. In the present study, the first attempt on dye decolourisation potentials of local microbial consortia isolated from dye contaminated soils in common effluent treatment plant were determined against two azo dyes. Decolourisation rate and kinetics were monitored by spectrophotometry under different conditions. Effect of process parameters: pH, dye concentration and inoculums size on dye decolourisation rate was optimised using the full factorial design. Microbial growth and decolourisation rate were higher in shaking than static conditions. The bacterial consortium gave highest decolourisation of 91.86% for Remazol Black and 93.75% for Mordant Orange within 48 hours in shaking cultures; 57.78% and 62.06% respectively after 48 hours under static condition, followed by the mixed and fungal consortium. Kinetics studies revealed the bacteria consortia had highest tendency towards decolourisation, with a greater half live value for Remazol Black (13.97 hours) than for Mordant Orange (10 hours). pH out of the range 7.2-8 and dye concentrations above 100mg/l reduced decolourisation rate by the bacteria consortia while increasing inoculums size increased it. Optimum decolourisation was achieved when pH and dye concentrations were kept low while the inoculums size was high.

Abstract: A bacterial consortium was constructed using five different bacterial strains isolated from the effluent with the ability to degrade Acid Blue, a diazo dye. These organisms were identified as Pseudomonas putida (2 strains-designated as A & B), Bacillus subtillis, Pseudomonas aeruginosa (2 strains) using 16S rRNA analysis. The consortium was found to degrade 90% of the dye by 22 h in 80% diluted textile effluent supplemented with glucose and ammonium nitrate. Optimization studies using Response Surface Methodology have confirmed that the degradation process was predominantly influenced by agitation and pH where as glucose was found to have negative effect. TLC analyses indicated the presence of metanilic acid and peri acid in 24 h sample which disappeared by 48 h. The GC-MS analysis has confirmed the presence of methyl salicylic acid, catechol and β-ketoadipic acid with the RT values of 7.71, 10.88 and 15.04 respectively confirming the complete degradation of Acid Blue.

Abstract: In this study we intended to isolate and identify azo dye degrading and decolorizing bacterial strains as well as investigation its biodegradation mechanism. Different bacterial isolates were isolated from activated sludge of common effluent treatment plant and tested against Reactive Violet 5 (RV5) dye. The most potent isolate was identified as Pseudomonas spp via partial sequencing of 16s rRNA DNA. The decolorized sample showed lowering of peak to a smaller absorbance value for dye concentration of 200 mg/L, which informs that the decolorization is due to removal or degradation of dye. The comparison of TLC chromatograms before and after decolorization by Pseudomonas spp under UV light showed that the original dye was quite different from the supernatant obtained after dye decolorization, which was suggested by different values of retention factors obtained in the TLC experiment This difference confirms that decolorization was due to breakdown of dyes into unknown products. The identification of several degradation products from purified RV5 by Pseudomonas spp was achieved with FTIR spectroscopy, 1H NMR and GC-MS. The results showed four compounds, nitrobenzene, 4-nitrophenol, 4-nitroaniline, and 4-nitroanisole, as degradation products.

Abstract: In the present study an attempt was made to examine the potential of two bacterial strains for decolorization of Remazol Black-B. The strain, isolated from textile effluent treatment plant was characterized on the basis of morphological, biochemical & genotypic characteristics & it was identified as Pseudomonas aeruginosa & Bacillus cereus. The effect of pH, temperature and initial concentration of dye was studied with an aim to determine the optimal conditions. The bacterial strains used in the study were Pseudomonas aeruginosa. ETL-1942 & Bacillus cereus ETL-1949. Out of this Pseudomonas aeruginosa. ETL-1942 emerged out to be most potent decolorizer, being selected for further studies. The selected bacterium shows higher decolorization in static condition as compared to shaking condition. The optimum pH was 7.0. It shows good decolorization efficiency even in alkaline region. The optimum temperature was 37C. The strain could decolorize Remazol Black-B (250 mg/l) by 94% within 24 h under static condition, pH 7.0, temperature of 37C and initial dye concentration of 250 mg/l. Biodegradation and decolorization was confirmed using UV-VIS spectrophotometry, thin layer chromatography (TLC) and fourier transform infrared spectroscopy (FTIR) analysis. The study confirmed the potential of Pseudomonas aeruginosa ETL-1942 in the bioremediation of Remazol Black-B.

Abstract: Urbanization in the world increased the pollution levels in the environment making it for worsen life. General awareness about pollution is increasing today. To control pollution levels, biological methods are eco-safe and economical. In this study a wild strain of Bacillus species was isolated and optimized for bioremediation studies of ammonia in flask cultures. Strategy was tried to develop for ammonia bioremediation in a single stage aerobic nitrification and denitrification. The results reveal that the optimum pH for the isolated Bacillus species was 7 and optimum temperature was 30°C. At optimum pH and temperature this organism was able to remove 99.2% of ammonia in flask cultures supplemented with 5g/L of ammonium sulphate. The biomass obtained after bioremediation studies was 0.3g/L which is very low. The study on ammonia toxicity revealed that toxicity was due to pH and osmolarity.

Abstract: Environmental pollution by petroleum is an increasing global problem with phytoremediation being one of the viable tools for cleansing crude oil polluted soil. The aim of this study was to ascertain the remediating effect of Piper guineense and Azadirachta indica on the levels of polycyclic aromatic hydrocarbons (PAH) on the leaves of deliberately crude oil polluted germinating Telfairia occidentalis. Vessel I contains growing plant and water only, vessel II contains growing plant + crude oil only, vessel III, IV and V had growing plant+crude oil + 100g of Azadirachta indica, 77g of P. guineense and 100g of Azadirachta indica +77g of P. guineense leaves respectively. After 8weeks of plant growth, the levels of polyaromatic hydrocarbons (PAH) in the plants were determined using gas chromatography. The result indicates that naphthalene levels were significantly higher (p<0.05) in plants grown on vessels with 77 g P. guineense (4.2 ± 0.003 µg/Kg) and 77 g P. guineense + 100 g A. indica (4.2 ± 0.007 µg/Kg) compared to the crude oil only vessel (2.1 ± 0.003 µg/Kg). Phenanthrene levels were significantly lower (p<0.05) in plants grown on vessels with 100 g A. indica (1.7 ± 0.002 µg/Kg) compared to levels in crude oil only grown plants (2.2 ± 0.003 µg/Kg). Acenaphthylene, acenaphthene, fluorene benzo(k)fluoranthene and benzo(a)pyrene levels were significantly higher (p<0.05) in plants grown in vessels III,IV and V compared to the crude oil only vessel. Also, dibenzo(a,b)anthracene and indenol(1,2,3cd)pyrene levels were significantly lower (p<0.05) in plants grown on vessels remediated with 100 g A. indica and 77 g P. guineense + 100 g A. indica when compared with plants grown in crude oil only vessel. Therefore, it could be concluded that P. guineense and A. indica leaves could be good for phytoremediation of phenanthrene, benzo(b)fluoranthene, dibenzo(a,b)anthracene and indeno(1,2,3cd)pyrene.

Abstract: A bacterium identified as Lactobacillus was isolated from acclimated sludge from a dyeing wastewater treatment plant. This strain rapidly decolorized Reactive orange (RO) at 0.1% (w/v) concentration of both sucrose and peptone supplemented in Mineral Salt Medium (MSM) under static conditions at a temperature of 30°C with in 24 h with an initial dye concentration of 100 mg/L. The organism exhibited a remarkable color removal capability (95%) even at a high concentration of 1000 mg/L (RO16) dye within 24 h. The biodegradation products were analyzed by, FTIR spectroscopy and LC-MS analysis. The LC-MS analysis indicated the presence of 1-amino- 1-napthalene sulphonic acid in degraded product of the dye.

Abstract: Over the past 40 years, research on the microbial degradation of polycyclic aromatic hydrocarbons (PAHs) has resulted in the isolation of numerous genera of bacteria, fungi and algae capable of degrading PAHs. With the development of biology, molecular techniques such as PCR, fingerprinting technique (mainly DGGE/TGGE), ARDRA, TRFLP, FISH, RISA and gene reporter technique have been intensively applied to gain further insight into the mechanism of PAHs degradation. Further recent developments in moleclar microbial ecology like genotypic profiling, ultrafast genome pyrosequencing, metagenomics, metatranscriptomics, metaproteomics and metabolomics along with bioinformatics tools offer new tools that facilitates molecular analyses of microbial populations at contaminated and bioremediated sites. Information provided by such analyses aids in the evaluation of the effectiveness of bioremediation and the formulation of strategies that might accelerate bioremediation. The potential for the use of molecular methods in toxicological risk assessment and in developing bioremediation strategies is expanding rapidly as new methodologies become available. In this paper we present an overview of some molecular methods we feel have the most potential for use in assessment and monitoring in the field.

Abstract: The burning issue of today,s environment problem is the release of toxic contaminants from various man made sources resulting in contamination of natural resources of earth and leading to scarcity of clean water and loss of soil fertility. To overcome these drawbacks,the concept of using plant to clean up contaminated environment is not new. about 300 years ago, plants were proposed for use in the treatment of waste water.land and water pollution by heavy metals is a world wide issue. therefore has been an increasing concern with regard to accumulation of heavy metals in environment as they pose big threat to both human health and natural environment. in central and eastern european countries about 1.7 million sites were contaminated with heavy metals and need reclamation. in developing countries particularly india, china, pakistan, bangladesh, soil and water pollution is also severe where small industrial units are pouring their untreated effluents over near agricultural fields.the use of plants species for cleaning polluted soils and water named as phytoremediation has gained increasing attention since last decade, as an emerging cheaper technology. This article reviewed the status of phytoremediation in global prospects.

Abstract: In the present research we evaluated the suitability of ARDRA method to detect differences in activated sludge bacterial communities fed on domestic or industrial wastewater, and subject to different operational conditions. The ability of this method to detect these differences has been tested in modified Ludzack-Ettinger configurations. Samples from three activated sludge wastewater treatment plants with the MLE configuration were collected for both oxic and anoxic reactors, and ARDRA patterns using double enzyme digestions AluI+MspI were obtained. A matrix of Dice similarity coefficients was calculated and used to compare these restriction patterns. Differences in the community structure due to influent characteristics and temperature could be observed, but not between the oxic and anoxic reactors of each of the three MLE configurations. Other possible applications of ARDRA for detecting and monitoring changes in activated sludge systems are discussed.