Decolourization and Detoxification of Azo Dye, Malachite Green by Pseudomonas monteilii Strain RZT1, a Bacterium Isolated from Textile Wastewater

Discharge of textile industrial effluent without proper treatment has become a severe hazard for the animal health and environment worldwide. Therefore, this study was designed to isolate azo dye-degrading bacteria from textile wastewater and evaluate their ability to biodegrade reactive dyes into non-toxic products. The potent bacterial strain which was isolated from textile wastewater was identified as Pseudomonas monteilii strain RZT1 on the basis of 16S rDNA sequence. The isolated bacterial strain exhibited good decolorization ability with yeast extract supplementation as cosubstrate in static conditions for Malachite Green dye. The optimal condition for the decolorization of Malachite Green dye by P. monteilii strain RZT1 were at pH 7.0 and 28癈. Decolorization rates of Malachite Green dye by P. monteilii strain RZT1 were varied with initial dye concentration as follow: 84.8%, 75.4%, 63.4% and 45.5% decolorization for 100ppm, 200ppm, 300ppm and 400ppm initial dye concentration respectively. We investigated the effects of dyes used in the textile industry on the seed germination of Five crops - Rice (Oryza sativa), Wheat (Triticum aestivum L.), Khesari (Lathyrus sativus), Mustard (Brassica nigra) and Bitter Melon (Momordica charantia). It was found that textile dye Malachite Green had negative effect on seed germination and seedling growth in test cultures. The harmful effects of dye on seed germination and early seedling growth parameters were augmented with increase of dye concentration. Interestingly, treatment of the Malachite Green dye with isolated bacteria reduced the adverse effects of that dye on seed germination and seedling growth. Thus, it indicated the potentiality of P. monteilii strain RZT1 for bioremediation of textile effluents into a non-toxic form for plants.

Reduction of Toxic Effects of Textile Dye, Basic Red-18 on Tilapia Fish by Bioremediation with a Novel Bacterium, Mangrovibacter yixingensis Strain AKS2 Isolated from Textile Wastewater

Due to rapid industrialization and market demand of vibrant textile products, the natural textile dyes have been replaced by the synthetic textile dyes. These synthetic dyes are released in environment with textile wastewater resulting in a major environmental pollution, especially in aquatic ecosystem. Hence, aquatic organisms like fish are highly vulnerable to the pollution caused by dyes of textile wastewater. This study was designed to evaluate the deleterious effects of Basic Red-18 (BR-18) dye on behavior, survivability, haematology and histology of Tilapia fish (Tilapia mossambica) and to minimize these deleterious effects of BR-18 dye by bioremediation with the novel bacteria isolated from textile wastewater. The isolated novel bacteria was identified as Mangrovibacter yixingensis strain AKS2 by 16s rRNA sequencing (Accession no. OM189530). The 30% and 70% mortality rates were observed in fish exposed to commercial BR-18 dye at concentrations of 100 and 200 ppm respectively. Interestingly, the mortality rate of fish was decreased significantly to 10% and 20% when fish were exposed to 100 and 200 ppm BR-18 dye respectively after bioremediation with M. yixingensis strain AKS2. Fish exposed to tap water and bioremediated BR-18 dye solution exhibited typical behavioral responses, whereas fish exposed to commercial BR-18 dye solution exhibited anomalous behavior. Fish subjected to commercial BR-18 dye solution displayed decreased RBC, Hb, but increased WBC levels, demonstrating the dye's haemotoxicity. Contrary, no remarkable haematological toxic effect was found when fish were exposed to bioremediated BR-18 dye indicating the non-toxic character of the bioremediated dye metabolites. Similarly, extensive histological abnormalities in the gill, liver, intestinal, stomach, and heart tissues were seen when fish was cultured in commercial BR-18 dye, but the abnormalities were less significant when fish were raised in bioremediated BR-18 dye. Altogether, it can be concluded that BR-18 dye are toxic to fish, but this toxicity can be minimized by bioremediation with M. yixingensis strain AKS2.

Isolation and Identification of Orange M2R and Green GS Dye Decolourizing Bacteria from Textile Sludge (Soil) Samples and Determination of Their Optimum Decolourization Conditions

Objectives: Azo dye accounts for majorly produced synthetic dye substances in industries, posing a threat to all possible life forms. This study was focused to isolate azo dye “Orange M2R” and “Green GS” degrading bacterial strain from textile effluent soil samples and optimization of their optimum physio-chemical growth conditions. Methodology: To achieve above-mentioned objective, sludge samples were collected from textile industrial area and were applied to 1%, 3% and 5% dye containing SM broth to observe the dye degrading capability of those samples that contain acclimatized bacteria. ABIS microbiology software (Advanced Bacterial Identification Software) was used to justify and determine the identity of these bacteria with the aid of results obtained from the biochemical tests that were undertaken. Results: Bacterial strains identified in this study were Enterococcus termitis, Enterococcus camelliae, Bacillus farraginis, Bacillus muralis, Paenibacillus macerans, Bacillus decolorationis, and Macrococcus brunensis. Out of these isolates Enterococcus termitis, Bacillus farraginis, Paenibacillus macerans, Bacillus decolorationis emerged out to be most potent decolourizer, being selected for further studies. Bacillus farraginis was identified as the best decolourizer of OM2R (Orange M2R) dye that decolourized 98% of the dye and Paenibacillus macerans showed maximum decolourization on GGS(Green GS) dye that decolourized 97% of the dye. The effect of pH, NaCl, temperature and initial concentration of dye was studied with an aim to determine the optimal conditions required for maximum decolourization. The research showed different decolourization rate with varying parameters. The optimum pH for decolourization of OM2R and GGS dye was 7.0, the optimum NaCl concentration for decolourization was 2%, initial dye concentration was 1% and the temperature was 37°C for optimum decolourization by the selected isolates. Conclusion: The findings are well acclimatized and have potentials for bioremediation in textile waste effluent treatment plants.

Screening of Decolorizing Agents for the Extracts from the Fruit and Stem of Schisandra chinensis / 中国药房

OBJECTIVE:To screen decolorizing agents suitable for the extracts from the fruit and stem of Schisandra chinen-sis. METHODS:HPLC was adopted to determine the contents of 4 kinds of lignans(schizandrin,schisandrol B,deoxyschizandrin and γ-schizandrin) in the extract solution from the fruit and stem of S. chinensis which was treated with 8 kinds of decolorizing agents (activated clay,activated carbon,diatomite,calcium bentonite,kaolin,activated aluminium oxide,magnesium oxide,at-tapulgite clay),and the decolourization rates of the samples of the fruit and stem of S. chinensis and the retention rates of lignans in such samples were calculated respectively. RESULTS:The above-mentioned decolorizing agents were arranged in order as fol-lows respectively based on the decolourization effects on the extract solution from the fruit and stem of S. chinensis:attapulgite clay>activated carbon>activated aluminium oxide>kaolin>magnesium oxide>diatomite>calcium bentonite>activated clay,and activated carbon>diatomite>attapulgite clay>magnesium oxide>kaolin>activated aluminium oxide>activated clay>calcium ben-tonite. The attapulgite clay and activated carbon have the best decolourization effects on the extracts from the fruit and stem of S. chinensis,with the decolourization rates of 60.47% and 69.24% respectively,and the retention rates of schizandrin,schisandrol B,deoxyschizandrin and γ-schizandrin were 77.43%,77.73%,77.07%,77.53%,and 72.18%,70.17%,70.32%,70.28%,re-spectively. CONCLUSIONS:Among the 8 decolorizing agents,attapulgite clay and activated carbon have the best decolourization effects on the extract solution from the fruit and stem of S. chinensis.

Application of decolourized and partially purified polygalacturonase and α-amylase in apple juice clarification

Polygalacturonase and α-amylase play vital role in fruit juice industry. In the present study, polygalacturonase was produced by Aspergillus awamori Nakazawa MTCC 6652 utilizing apple pomace and mosambi orange (Citrus sinensis var mosambi) peels as solid substrate whereas, α-amylase was produced from A. oryzae (IFO-30103) using wheat bran by solid state fermentation (SSF) process. These carbohydrases were decolourized and purified 8.6-fold, 34.8-fold and 3.5-fold, respectively by activated charcoal powder in a single step with 65.1%, 69.8% and 60% recoveries, respectively. Apple juice was clarified by these decolourized and partially purified enzymes. In presence of 1% polygalacturonase from mosambi peels (9.87 U/mL) and 0.4% α-amylase (899 U/mL), maximum clarity (%T660nm = 97.0%) of juice was attained after 2 h of incubation at 50 ºC in presence of 10 mM CaCl2. Total phenolic content of juice was reduced by 19.8% after clarification, yet with slightly higher %DPPH radical scavenging property.

Optimization of phenoxazinone synthase production by response surface methodology and its application in Congo red decolourization

Background: Enzymatic decolourization has been recently proposed as a promising and eco-friendly method for treatment of synthetic dye-contaminated wastewaters. However, the processes require large quantities of enzymes, attracting significant attention in developing efficient methods for mass production of multifunctional enzymes. Several methods such as response surface methodology (RSM) and orthogonal experiment have been applied to optimize the parameters in bioprocesses for enzyme production. Results: In the present study, a laccase-like enzyme, phenoxazinone synthase (PHS) originated from Streptomyces antibioticus was recombinantly expressed in Escherichia coli BL21 (DE3). The production of PHS in E. coli BL21 was optimized by response surface methodology based on Box-Behnken design. A full third-order polynomial model was generated by data analysis with Statistica 8.0 in which the optimal conditions for PHS production were calculated to be 1.525 mM CuSO4 and 16.096 hrs induction at temperature of 29.88ºC. The highest PHS production under optimal conditions was calculated to be 4098.51 U/l using the established model. Average PHS production obtained from actual production processes carried out under the calculated optimal conditions was 4052.00 U/l, very close to the value predicted by the model. Crude PHS was subsequently tested in Congo red decolourization which exhibited a low decolourization rate of 27% without mediator. Several mediators were found to improve PHS-catalyzed Congo red decolourization, with the highest rate of 73.89% obtained with 2,2’-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) as mediator under optimized conditions of 4000 U/l PHS activity, 10 μM ABTS, 100 μM Congo red, and 8 hrs reaction time. Conclusion: Our results indicated that PHS recombinantly produced in E. coli BL21 was a prospective enzyme for decolorizing reactive dye Congo red.

Decolorization of two azo dyes using marine Lysobacter sp. T312D9

Aims: Novel azo dye-degrading bacterium T312D9 strain has been isolated from Abou Quir Gulf, Alexandria, Egypt. Methodology and Results: The identification of the isolate by 16S rRNA gene sequencing revealed to be Lysobacter sp. This marine ecofriendly isolate was exploited for its ability to degrade two synthetic azo dyes considered as detrimental pollutants from industrial effluents: congo red and methyl red. Using different dye concentrations showed the highest metabolic activity for complete degradation obtained from 100 to 500 mg/L within 30 h under static condition, also, sustaining higher dye loading of 1 g/L was carried out. The significant induction of enzymes NADH - 2,6-dichloroindophenol (NADH-DCIP) reductase and tyrosinase indicated their prominent role in dye degradation. The biodegradation of two azo dyes were analyzed by gas chromatographicmass spectrum analysis (GC-MS) and Fourier transform infrared spectroscopy (FTIR) before and after treatment. Toxicity study revealed the much less toxic nature of the metabolites produced after complete decolorization. Conclusion, significance and impact of study: Lysobacter sp T312D9 represent an inexpensive and promising marine bacteria for removal of both methyl and congo red. High sustainable metabolic activity for biodegradation under static condition. NADHDCIP reductase and tyrosinase were significantly induced during biodegradation of dyes. The obtained metabolites revealed to be less toxic in nature which offers a practical biological treatment.

Selection of white-rot fungi to formulate complex and coated pellets for Reactive Orange 165 decolourization

Six strains of white-rot fungi isolated from southern Chile were evaluated for their ergosterol/biomass correlation and ligninolytic potential in solid medium to formulate pellets for Reactive Orange 165 (RO165) decolourization. The fungus Anthracophyllum discolor was selected to formulate complex pellets (fungal mycelium, sawdust, and activated carbon), coated pellets (complex pellet + alginate) and simple pellets (fungal mycelium). The activity of ligninolytic enzymes (laccase, manganese peroxidase, manganese-independent peroxidase, and lignin peroxidase) was evaluated in both the complex and coated pellets in modified Kirk medium, and the morphology of the pellets was studied using scanning electron microscopy (SEM). Complex pellets of A. discolor showed a higher enzymatic production mainly MnP (38 U L-1 at day 15) compared to coated and simple pellets. Examinations using SEM showed that both pellets produced a black core that was entrapped by a layer of fungal mycelium. Decolourization of RO165 was demonstrated with all the pellets formulated. However, the highest and fastest decolourization was obtained with complex pellets (100 percent at day 8). Therefore, complex pellets of A. discolor can be used for the biological treatment of wastewater contaminated with RO165.

Decolourization of textile dye effluent by non-viable biomass of Aspergillus fumigatus

The aim of this work was to study the decolourization of textile dye effluent by non-viable biomass of Aspergillus fumigates. The dried non-viable fungal biomass exhibited maximum dye removal at pH 7.0 with temperature of 30ºC and 3 g/l (w/v) biomass concentration, after 24 h contact time. The results showed that the non-viable biomass possessed high efficiency for dye removal from textile effluent.