Response surface methodology for optimization of the treatment of textile wastewater by a novel bacterial consortium: Enzymes and metabolites characterization (original) (raw)
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Biometrics & Biostatistics International Journal, 2019
Textile wastewaters (TWWs) are characterized by high salinity and alkaline pH. Bioremediation using fungi were proved in many cases as inefficient tools to treat such effluent, giving the relay to haloalkaliphilic bacteria. Here, three extremophilic strains namely Halomonas desertis G11, Kocuria rosea BU22S and Microbaterium trichothecenolyticum TL13 have been selected to conduct textile dye decolorization experiments. The effect of different combinations of these strains was studied by a mixture design (MD) to assess Tubantin Brown GGL (TB GGL) color removal during species growth under optimzed conditions of dye concentration (100 mg/L), pH (9), salinity (5%), inoculum size (5%) and time (10 days). A remarkable decolorization was observed using mono and mixed cultures. Using the NemrodW software, the optimisation calculations were performed to find an optimum mixture proportions for maximum azo dye decolorization. High regression coefficients R2, between the variables and the response indicated excellent evaluation of experimental data by the polynomial regression model. The highest color removal (about 92%) was obtained with binary mixture composed by H. desertis G11and M. trichothecenolyticum TL13 and it was in close agreement with the estimated response value (93%). This finding shows a biotechnological potential of haloalkaliphilic bacteria in TWWs treatment.
Decolourisation of dye and removal of COD from textile wastewater using biodegradation method
2020
Department of Chemical Engineering, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata-700 009, India E-mail: bmandal20@yahoo.co.in Manuscript received online 05 January 2020, accepted 21 June 2020 A study has been conducted on the biodegradation of dye and removal of chemical oxygen demand (COD) from textile waste water using mixed microbial culture in batch mode process. The microbial consortium was isolated from textile dye wastewater. The effect of process parameters namely, pH, temperature and initial dye concentration on decolourisation and COD reduction of textile waste effluent were studied. The process parameters were optimised using response surface methodology (RSM) based on central composite design (CCD). The experimental results were analysed statistically to evaluate analysis of variance (ANOVA). The optimum values of pH, temperature and initial dye concentration were 7, 30ºC and 327 mg/L, respectively. Under optimum process condition, the percent remov...
Journal of Cleaner Production, 2016
The biological colour removal from textile wastewater is challenging because of the toxicity of dyes to microorganisms, and the need to test the process on real streams in order to ensure the reliability of the produced data. This present study has provided a comparative analysis of the biodecolorization of a real wastewater containing a mixture of azo dyes under different environments: single aerobic and anaerobic, and sequential anaerobic-aerobic. Tests were performed in sequencing batch reactors operated at different exchange ratios and colour loads in the range of 0.1-0.3 and 0.002-0.1 kg COD m-3 d-1 , respectively. The work cycle lasted 24 hours. With reference to the dominant wavelength, λ = 536 nm, resulting from the influent characterization, a maximum limit value of ~30% was observed for the colour removal in the aerobic system. Better performance has been achieved with the anaerobic (65% removal) and the sequential anaerobic-aerobic system, which reached efficiencies of 70-80%, for the range of applied colour loads. The sequential system exhibits the highest removal rate, which, for the highest colour load, is equal, in terms of absorbance units to 0.043 AU d-1 L-1. These values are even higher than the process rates obtained with more complex technologies, such as the granular sludge bioreactors. The demonstrated high performance of the sequential process with a real wastewater is a relevant step forward for promoting the application of the biological treatment (more sustainable than the generally employed chemical physical ones) to remediate highly polluted dye streams.
Ecotoxicology and Environmental Safety, 2011
Present study illustrates the effectual decolorization and degradation of the textile effluent using a developed bacterial consortium SDS, consisted of bacterial species Providencia sp. SDS and Pseudomonas aeuroginosa strain BCH, originally isolated from dye contaminated soil. The intensive metabolic activity of the consortium SDS led to complete decolorization of textile effluent within 20 h at pH 7 and temperature 30 °C. Significant induction in the activities of veratryl alcohol oxidase, laccase, azoreductase and DCIP reductase were observed during decolorization, which indicates their involvement in decolorization and degradation process. The decolorization and biodegradation was monitored using UV–vis spectroscopy, IR spectroscopy, HPLC and HPTLC analysis. Toxicological analysis of effluent before and after treatment was performed using classical Allium cepa test. Investigations of various toxicological parameters viz, oxidative stress response, cytotoxicity, genotoxicity and phytotoxicity, collectively concludes that, the toxicity of effluent reduces significantly after treatment with consortium SDS.
Trends in Sciences
The increasing demands in textile industries has created huge production of textile coloured products globally, leading to large production of textile effluent. Textile effluent is often discharged to the environment without proper treatment by the textile factories. The untreated textile effluent typically contains harmful chemicals and is hazardous to the environment, due to the toxicity of the dyes used. In this study, biological treatment is applied to the textile effluent. A 2-level full factorial design from response surface methodology (RSM) was applied to find the optimized treatment process condition for the textile wastewater degradation. Sixteen runs of experiment with 4 factors were performed; bacterial inoculum (%, v/v), temperature (℃), agitation (rpm), and pH were tested. It was observed highest decolourization obtained (91.95 % with pH 4, low concentration of bacterial inoculum (5 %), agitation speed (200 rpm) and temperature (40 ℃)) meanwhile lowest decolourization ...
Bioresource Technology, 2009
A developed consortium-GR, consisting of Proteus vulgaris NCIM-2027 (PV) and Micrococcus glutamicus NCIM-2168 (MG), completely decolorized an azo dye Scarlet R under static anoxic condition with an average decolorization rate of 16,666 lg h À1 ; which is much faster than that of the pure cultures (PV, 3571 lg h À1 ; MG, 2500 lg h À1 ). Consortium-GR gave best decolorization performance with nearly complete mineralization of Scarlet R (over 90% TOC and COD reduction) within 3 h, much shorter relative to the individual strains. Induction in the riboflavin reductase and NADH-DCIP reductase was observed in the consortium, suggesting the involvement of these enzymes during the fast decolorization process. The FTIR and GC-MS analysis showed that 1,4-benzenediamine was formed during decolorization/degradation of Scarlet R by consortium-GR. Phytotoxicity studies revealed no toxicity of the biodegraded products of Scarlet R by consortium-GR. In addition, consortium-GR applied for mixture of industrial dyes showed 88% decolorization under static condition with significant reduction in TOC (62%) and COD (68%) within 72 h, suggesting potential application of this microbial consortium in bioremediation of dye-containing wastewater.
Chemical Engineering Journal, 2010
The use of chemometric methods such as response surface methodology (RSM) based on statistical design of experiments (DOEs) is becoming increasingly widespread in several sciences such as analytical chemistry, engineering and environmental chemistry. In the present study, the decolorization and the degradation efficiency of Methyl Orange (MO) was studied using a microbial consortium. The microbial growth of Sphingomonas paucimobilis, Bacillus cereus ATCC14579, Bacillus cereus ATCC11778 is well in the presence of MO (750 ppm) within 48 h at pH 7 and 30 • C. In fact, these microorganisms were able to decolorize and to degrade MO to 92%. The degradation pathway and the metabolic products formed during the degradation were also predicted using UV-vis, Fourier transform infrared (FTIR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy analysis. Under optimal conditions, the bacterial consortium was able to decolorize completely (>84%) the dye within 48 h. The color and COD removal were 84.83% and 92.22%, respectively. A significant increase in azoreductase, lignin peroxidase and laccase activities in the cells were obtained after complete decolorization. Phytotoxicity study using plants showed no toxicity of the produced products.
Decolourisation of a synthetic textile effluent using a bacterial consortium
Biotechnology Journal, 2007
Azo dyes are easily reduced to colourless amines; however, in conventional biological treatment systems, like activated sludge, the prevailing aerobic conditions usually prevent complete reductive azo dye decolourisation . Therefore, the treated water still needs some kind of tertiary treatment. Additional problems met in the treatment of wastewaters generated by dyeing with reactive azo dyes are the high temperature and pH values and the high salt content of reactive dye baths . Therefore, in the last few years, intensive research has been performed in the azo dye biodegradation area, mainly with bacteria, either isolated or in consortia , aiming at the pro-duction of wastewaters complying with the applicable legislation. In Portugal, for instance, the limits for discharge of effluents from textile industries are as follows: pH between 5.5 and 9 (Sorensen scale), biochemical oxygen demand after 5 days <100 mg O 2 /L, chemical oxygen demand (COD) <250 mg O 2 /L, and colour not visible at a dilution of 1:40 [12]. These limits prevail over general regulations [13] for the discharge of residual waters. In a biological system for wastewater remediation, the first consideration to be made relates to the choice of the biological material. In this respect, the use of bacterial consortia has several advantages. Firstly, they do not require sterile conditions, thus greatly reducing costs. Secondly, they are usually more stable towards changes in pH, temperature and feed composition, when compared with pure cultures . Finally, there is a higher possibility of a complete mineralization of the dye since few strains have been found that can metabolise these types of compounds alone . However, the operational parameters of a biological treatment system greatly influence its efficiency, and parameters such as hydraulic retention time Short Communication
2014
Crude ligninolytic enzymes extract from Schyzohyllum commune IBL-06 having high activities of LiP (2186.02 U mL −1), MnP (1676.75 U mL −1) and laccase (259.07 U mL −1) was used for bioremediation of textile industry effluents. Response Surface Methodology (RSM) was adopted using D-optimal design to optimize the effluent decolorization process. The effects of different mediators on effluent decolorization were also investigated under preoptimized conditions. The optimum conditions for maximum decolorization of the effluents collected from Khyber Textile (KHT), Ishaq Textile (IST), Kalash Textile (KAT) and Masood Textile (MAT) industries of Faisalabad, Pakistan were: initial pH 4.5; temperature, 35 • C; effluent concentration, 180 ppm and veratryl alcohol (mediator), 1 mM. It was noted that values of water quality parameters including pH, color, biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), total organic carbon (TOC) and formaldehyde for enzyme treated effluents were within permissible limits set by the National Environmental Quality Standards (NQS). Analysis of peaks in HPLC profiles for treated and untreated effluents confirmed the degradation of residual dyes by ligninolytic enzymes extract of S. commune IBL-06.