Isolated Enterococcus faecalis YZ 66 strain shows ability to decolorize various industrial dyes among which, it showed complete decolorization and degradation of toxic, sulfonated recalcitrant diazo dye Direct Red 81 (50 mg/L) within 1.5 h of incubation under static anoxic condition. The optimum pH and temperature for decolorization was 7.0 and 40°C, respectively. Significant induction in the activity of intracellular oxidoreductive enzymes suggested its involvement in the decolorization of Direct Red 81. The biodegradation of Direct Red 81 was monitored by UV-Visible, FT-IR spectroscopy and HPLC. The final products were characterized by GC-MS and possible pathway of the degradation of the dye was proposed. The phytotoxicity assay (with respect to plants Sorghum vulgare and Phaseolus mungo) revealed that the degradation of Direct Red 81 produced nontoxic metabolites. Finally E. faecalis was employed to decolorize actual industrial effluent showing decolorization (in terms of ADMI value) with moderate COD and BOD reduction. Moreover the result increases the applicability of the strain for the treatment of industrial wastewaters containing dye pollutants.Electronic supplementary materialThe online version of this article (doi:10.1186/s40201-014-0151-1) contains supplementary material, which is available to authorized users.

The present investigation was aimed to assess the effect of cadmium chloride on some biochemical parameters and the potential of cadmium uptake of Eichhornia crassipes. The effects of increasing concentrations of cadmium chloride on growth characteristics of E. crassipes including root length, leaf area and biomass production was studied. The root growth of E. crassipes was severely affected at all concentrations of cadmium in the trays where plants were grown and in general it was serially increased. Similar trend was observed in average leaf area with 11.28 cm2 on 12th day in control while with only 7.05 cm2 at 75 ppm concentration. Chlorophyll contents were also observed to be decreased serially with the increasing concentrations of CdCl2. The lowest total chlorophylls were 118.56 mg/100g in comparison with 239.09 mg/100g in control set at the end of treatment. Polyphenol and proline contents were increased indicating the stress conditions due to toxicity of cadmium. Highest polyphenol and proline were 303.27 mg/100g and 8.14 mg/100g respectively at 50 ppm set of the treatment. Moreover, Electrical conductivity and total dissolved solids content of the various dilutions were decreased remarkably after 12 days of treatment. pH of the solution tend to become neutral while increase in turbidity might be related with root exudates and dead organics by the plants growing in the tray whereas decrease in hardness, acidity, sodium and potassium content was observed with increase in concentration. Values for BOD and COD were slightly increased at the end of treatment. Estimation of bioconcentration factor is very much important. It indicates that the species is more favourable to tolerate higher concentrations of heavy metals and also helps a lot in decontamination of the land, water etc. In this study increasing concentration of cadmium showed higher accumulation capacities and may be better treatment option for cadmium by means of phytoremediation

Synthetic dyes are extensively used in textile dyeing, paper, printing, colour photography, pharmaceutics, cosmetics and other industries. Among these, azodyes represents the largest and most versatile class of synthetic dyes. As high as 50% of the dyes are released into the environment during manufacture and usage. Traditional methods of treatment are found to be expensive and have operational problems. Biological decolourization has been investigated as a method to transform, degrade or mineralize azo dyes. In the present studies bacteria from soil from dye waste area, dye waste, sewage and dung were subjected to acclimatization with C.I. Reactive Red 195 an azo dye, in the basal nutrient media. The most promising bacterial isolate was used for further dye degradation studies. The 16s rRNA gene sequencing and biochemical characteristics revealed the isolated organism as Enterococcus faecalis strain YZ66. The strain showed 99.5% decolourization of the selected dye (Reactive Red 195-50 mg/l) within one and half hour in static anoxic condition. The optimum pH and temperature for the decolourization was 5.0 and 40°C respectively. The biodegradation was monitored by UV-Vis, FTIR, TLC and HPLC. The final products were characterized by Gas chromatography and Mass Spectrophotometry. Toxicity study demonstrated no toxicity of the biodegradation product. The results suggest that the isolated organism E. faecalis strain YZ 66 can be used as a useful tool to treat waste water containing reactive dyes.

Background Tendu (Diospyros melanoxylon RoxB.) leaf is widely used in India in the form of wrapper for making a crude smoking stick popularly known as ''Beedi''. Solapur city of Maharashtra state has large number of small beedi making units. Large quantity waste from these industries in the form of trimmed leaf residues is available as feed material for preparation of vermicompost. The present investigations were aimed to study effect of vermicompost prepared from such novel leaf residues as the tendu leaves on the growth and yield of Phaseolus vulgaris under greenhouse conditions. The seeds of French bean were sown in cement pots containing soil alone (control), soil with various concentrations of vermicompost alone, soil with various concentrations of urea only and different admixtures of vermicompost and urea. Results The study revealed that the seed germination, shoot and root length, shoot and root fresh weights, shoot and root dry weights, thousand grain weight and grain weight per plant increased significantly (p B 0.05) compared to control due to application of vermicompost when used at proper proportions. Thus, the growth and yield parameters were significantly (p B 0.05) greater in T 2 (75 % N through vermicompost) than in T 1 (100 % N through vermicompost) and T 3 (50 % N through vermicompost). Many growth parameters of T 1 were lower than those in the control indicating some deleterious effect of vermicompost at higher concentrations. The combined application of tendu leaf vermicompost and urea increased the growth and yield of Phaseolus vulgaris significantly (p B 0.05). The maximum grain yield was due to combined application of vermicompost at 25 % N through vermicompost plus 75 % N through urea. Conclusions The pot trial experiments suggested that the quantity of chemical fertilizer for French bean could be reduced by 25-50 % due to combined application of vermicompost and chemical fertilizer. However, application of tendu leaf vermicompost alone at higher concentrations may reduce growth parameters and yield of P. vulgaris.

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