Fixed-bed decolorization of Reactive Blue 172 by Proteus vulgaris NCIM-2027 immobilized on Luffa cylindrica sponge

Proteus vulgaris NCIM-2027 cells immobilized on Luffa cylindrica (Loofa) completely decolorized C.I. Reactive Blue 172 at 37 °C and pH 8.0 under 5-h static incubation with high total organic carbon (TOC) and chemical oxygen demand (COD) reduction. The repeated-batch decolorization experiments also indicate good reusability of the immobilized biocatalyst. Some oxidoreductive enzymes were shown to be involved in the decolorization and degradation process. Loofa immobilized cells were also able to decolorize a mixture of reactive dyes in batch mode (in terms of ADMI value) with significant reduction in TOC and COD. Loofa immobilized cells were also used for continuous decolorization of individual and mixture of reactive dyes in a fixed bed bioreactor.     

Decolorization and biodegradation of reactive dyes and dye wastewater by a developed bacterial consortium

A bacterial consortium (consortium GR) consisting of Proteus vulgaris NCIM-2027 and Micrococcus glutamicus NCIM-2168 could rapidly decolorize and degrade commonly-used sulfonated reactive dye Green HE4BD and many other reactive dyes. Consortium GR shows markedly higher decolorization activity than that of the individual strains. The preferable physicochemical parameters were identified to achieve higher dye degradation and decolorization efficiency. The supplementation of cheap co-substrates (e.g., extracts of agricultural wastes) could enhance the decolorization performance of consortium GR. Extent of mineralization was determined with TOC and COD measurements, showing nearly complete mineralization of Green HE4BD by consortium GR (up to 90% TOC and COD reduction) within 24 h. Oxidoreductive enzymes seemed to be involved in fast decolorization/degradation process with the evidence of enzymes induction in the bacterial consortium. Phytotoxicity and microbial toxicity studies confirm that the biodegraded products of Green HE4BD by consortium GR are non-toxic. Consortium GR also shows significant biodegradation and decolorization activities for mixture of reactive dyes as well as the effluent from actual dye manufacturing industry. This confers the possibility of applying consortium GR for the treatment of industrial wastewaters containing dye pollutants.     

Ecofriendly degradation of sulfonated diazo dye C.I. Reactive Green 19A using Micrococcus glutamicus NCIM-2168

Micrococcus glutamicus NCIM-2168 exhibited complete decolorization and degradation of C.I. Reactive Green 19A (an initial concentration of 50 mg l⁻¹) within 42 h at temperature 37 °C and pH 8, under static condition. Extent of mineralization was determined with total organic carbon (TOC) and chemical oxygen demand (COD) measurement, showing a satisfactory reduction of TOC (72%) and COD (66%) within 42 h. Enzyme studies shows involvement of oxidoreductive enzymes in decolorization/degradation process. Analytical studies of the extracted metabolites confirmed the significant degradation of Reactive Green 19A into various metabolites. The microbial toxicity and phytotoxicity assay revealed that the degradation of Reactive Green 19A produced nontoxic metabolites. In addition, the M. glutamicus strain was applied to decolorize a mixture of ten reactive dyes showing a 63% decolorization (in terms of decrease in ADMI value) within 72 h, along with 48% and 42% reduction in TOC and COD under static condition.     

A new alternative process for Kraft E1 effluent treatment

Lentinus edodes (UEC-2019 strain) was selected after screening 51 ligninolytic strains of fungi for their ability to decolorize phenolic industrial effluent with high content of lignin peroxidases, Mn-peroxidases and beta-glucosidases. This strain removed 73 % of color in theEucalyptus Kraft E1 effluent in 5 days without any additional carbon sources. A 13% mycelial adsorption was found. Correlation between mass loss, COD, TOC and decolorization was observed. When an effluent pre-irradiated (10 min) in the presence of ZnO was treated withL. edodes, a marked enhancement of the decolorization at 48 h was obtained.L. edodes is an active fungus in this pre-treatment and biobleaching process. The combined photo-biological decolorization procedure appears to be an efficient decontamination method with great potential in industrial effluent treatment.Abbreviation COD Chemical oxygen demand - TOC Total organic carbon     

Enhanced decolorization and biodegradation of textile azo dye Scarlet R by using developed microbial consortium-GR

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 μg h^?1; which is much faster than that of the pure cultures (PV, 3571 μg h^?1; MG, 2500 μg h^?1). 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.     

Bioaugmentation of the decolorization rate of acid red GR by genetically engineered microorganism <Emphasis Type="Italic">Escherichia coli</Emphasis> JM109 (pGEX-AZR)

The study showed that the genetically engineered microorganism (GEM) bioaugment successfully the dye wastewater biotreatment systems to enhance acid red GR (ARGR) removal. Escherichia coli JM109 (pGEX-AZR) was the GEM with higher azoreductase activity. The kinetics of the ARGR decolorization by the E. coli JM109 (pGEX-AZR) agreed with Andrews model. The kinetic parameters, r _dye,max, K _s and K _i , were found to be 42.45 mg g⁻¹ h⁻¹, 584.93 mg L⁻¹ and 556.89 mg L⁻¹, respectively. The E. coli JM109 (pGEX-AZR) was tested in anaerobic sequencing batch reactors (AnSBR) in order to enhance the ARGR decolorization. The decolorization rate of ARGR was affected by the amount of E. coli JM109 (pGEX-AZR) inoculation and the best amount of inoculation was 10%. The continuous operations of the four bioreactors with different E. coli JM109 (pGEX-AZR) immobilization supports showed that the E. coli JM109 (pGEX-AZR) could bioaugment decolorization in AnSBRs with suspended and immobilized on macroporous foam carriers. For 42 days continuous operation in the AnSBRs, both the tolerance to ARGR concentration shock and the decolorization rate in these two bioaugmented AnSBRs are higher than those of the other two systems, control system and bioaugmented AnSBRs system with the sodium-alginate immobilized cells, the decolorization rate reached 90%. Changes in microbial community were detected by ribosomal intergenic spacer analysis (RISA) and amplified ribosomal DNA restriction analysis (ARDRA), which revealed that the introduced E. coli JM109 (pGEX-AZR) was persistent in the augmented systems and maintained higher metabolic activity.     

A new approach to study the decolorization of complex reactive dye bath effluent by biosorption technique

This work focused on the development of a practical biosorbent for the decolorization of textile effluents. The fermentation waste, Corynebacterium glutamicum biomass, when decarboxylated and immobilized in polysulfone matrix performed well in decolorization of simulated reactive dye bath effluent comprised of four different reactive dyes and other auxiliary chemicals. The regeneration of polysulfone-immobilized C. glutamicum was successful with the aid of 0.01 M NaOH as the eluant, which enabled the biosorbent to maintain consistent decolorization efficiency for up to 25 cycles. An up-flow packed column loaded with polysulfone-immobilized biomass performed well in the continuous treatment of Remazol effluent. Samples collected after 14 h of column operation revealed almost zero color and TOC. The column was also able to decrease the TDS level from 55,840 to 33,480 mg/L. Column regeneration experiments revealed that the biosorbent was able to continuously treat Remazol effluent over ten cycles, with more than 90.6% decolorization efficiency.     

Fe(III)-enhanced Azo Reduction by <Emphasis Type="Italic">Shewanella decolorationis</Emphasis> S12

Shewanella decolorationis S12 is capable of high rates of azo dye decolorization and dissimilatory Fe(III) reduction. Under anaerobic conditions, when Fe(III) and azo dye were copresent in S12 cultures, dissimilatory Fe(III) reduction and azo dye biodecolorization occurred simultaneously. Furthermore, the dye decolorization was enhanced by the presence of Fe(III). When 1 mM Fe(III) was added, the methyl red decolorizing efficiency was 72.1% after cultivation for 3 h, whereas the decolorizing efficiency was only 60.5% in Fe(III)-free medium. The decolorizing efficiencies increased as the concentration of Fe(III) was increased from 0 to 6 mM. Enzyme activities, which mediate the dye decolorization and Fe(III) reduction, were not affected by preadaption of cells to Fe(III) and azo dye nor by the addition of chloramphenicol. Both the Fe(III) reductase and the azo reductase were membrane associated. The respiratory electron transport chain inhibitors metyrapone, dicumarol, and stigmatellin showed significantly different effects on Fe(III) reduction than on azo dye decolorization.     

Semicontinuous decolorization of azo dyes by rotating disc contactor immobilized with<Emphasis Type="Italic">Aspergillus sojae</Emphasis> B-10

Aspergillus sojae B-10 was immobilized and used to treat model dye compounds. The model wastewater, containing 10 ppm of azo dyes such as Amaranth, Sudan III, and Congo Red, was treated with cells attached to a rotating disc contactor (RDC). Amaranth was decolorized more easily than were Sudan III and Congo Red. Decolorization of Amaranth began within a day, and the dye was completely decolorized within 5 days of incubation. Both Sudan III and Congo Red were almost completely decolorized after 5 days of incubation. Semicontinuous decolorization of azo by reusing attached mycelia resulted in almost complete decolorization in 20 days. This experiment indicated that decolorization was successfully conducted by removing azo dyes withAspergillus sojae B-10.     

Decolorization of the anthraquinone dye Cibacron Blue 3G-A with immobilized <Emphasis Type="Italic">Coprinus cinereus</Emphasis> in fluidized bed bioreactor

Coprinus cinereus, which was able to decolorize the anthraquinone dye Cibacron Blue 3G-A (CB) enzymatically, was used as a biocatalyst for the decolorization of synthetic solutions containing this reactive dye. Coprinus cinereus was immobilized in both calcium alginate and polyacrylamide gels, and was used for the decolorization of CB from synthetic water by using a fluidized bed bioreactor. The highest specific decolorization rate was obtained when Coprinus cinereus was entrapped in calcium alginate beads, and was of about 3.84 mg g⁻¹ h⁻¹ with a 50% conversion time (t _1/2) of about 2.60 h. Moreover, immobilized fungal biomass in calcium alginate continuously decolorized CB even after 7 repeated experiments without significant loss of activity, while polyacrylamide-immobilized fungal biomass retained only 67% of its original activity. The effects of some physicochemical parameters such as temperature, pH and dye concentration on decolorization performance of isolated fungal strain were also investigated.     

Decolorization of Azo Dyes with Enterobacter agglomerans Immobilized in Different Supports by Using Fluidized Bed Bioreactor

Immobilized cells of Enterobacter agglomerans, able to reduce azo dyes enzymatically, were used as a biocatalyst for the decolorization of synthetic medium containing the toxic azo dye methyl red (MR). This bacterial strain exhibits high ability to completely decolorize 100 mg/L of MR after only 6 h of incubation under aerobic conditions. Cells of E. agglomerans were immobilized in calcium alginate, polyacylamide, cooper beech, and vermiculite, and were used for the decolorization of MR from synthetic water by using a fluidized bed bioreactor. The highest specific decolorization rate was obtained when E. agglomerans was entrapped in calcium alginate beads and was of about 3.04 mg MR/g cell/h with a 50% conversion time (t_1/2) of about 1.6 h. Moreover, immobilized cells in calcium alginate continuously decolorized MR even after seven repeated experiments without significant loss of activity, while polyacrylamide-, cooper beech-, and vermiculite-immobilized cells retained only 62, 15, and 13% of their original activity, respectively.     

Modelling for waste water treatment by Rhodopseudomonas palustris Y6 immobilized on fibre in a columnar bioreactor

A kinetic model of continuous treatment of waste water by Rhodopseudomonas palustris Y6 immobilized on soft fibre in a columnar bioreaction system was established. Good agreement was found between the model prediction and the experimental data from continuous operation [initial chemical oxygen demand (COD) concentration = 29.700 g/l] of the system. The optimum operational conditions for the maximum COD reduction capacity were investigated from the model prediction and the experimental data. The waste water treatment process may significantly increase the waste reduction capacity because a large amount of active biomass for COD reduction is immobilized in the system, resulting in operation stability. The results presented here provide a useful basis for further scaling up and efficient operation of waste water treatment processes.     

Development of a bioreactor system using an immobilized white rot fungus for decolorization

In this paper the fixed film reactor system containing immobilized Phanerochaete chrysosporium cells was employed for decolorization of Red 533 dispersed dye. The inlet dye concentration and the inlet flow rate were shown to affect the decolorization efficiency. Each decolorization process was conducted continuously for 10–20 days or more and the decolorization efficiency remained higher than 80%. The immobilized cultures possessed good biological activities and the biodegrading system also showed capability for a long term operation.     

Laccase-mediated Remazol Brilliant Blue R decolorization in a fixed-bed bioreactor

A crude laccase mixture preparation from Pleurotus ostreatus cultures supplemented with copper and ferulic acid was used to decolorize the anthraquinonic dye Remazol Brilliant Blue R (RBBR). Performance of this enzymatic system was tested, and a maximum of 70% decolorization was achievable under optimal conditions. The crude preparation was immobilized by entrapment in copper alginate beads attaining 65% yield of laccase activity. Stability of the immobilized laccases was remarkably increased in comparison with that of the free enzyme preparation. Efficiency of the immobilized system was evaluated during stepwise dye additions in batch operations. Under the best conditions, 70% RBBR decolorization was achieved even after 20 cycles, although decolorization time exponentially increased after the 10th cycle. Different fixed-bed bioreactors were prepared and analyzed in continuous decolorization processes. The best performance was obtained by decreasing the amount of enzyme loaded and by improving laccase retention using chitosan-coated alginate beads.     

Decolorization of azo dye using PVA-immobilized microorganisms

A microbial consortium having a high capacity for rapid decolorization of azo dye (RED RBN) was immobilized by a phosphorylated polyvinyl alcohol (PVA) gel. The immobilized-cell beads exhibited a color removal capability of 75%, even at a high concentration of RED RBN (500 mg l(-1)) within 12 h using flask culture. The continuous operation was conducted at a hydraulic retention time (HRT) of 5-20 h in which the dye loading rate ranged from 240 to 60 mg dye h(-1). A removal efficiency exceeding 90% was obtained at the HRT higher than 10 h. No recognizable destruction of bead appearance was observed in the 6-month operation. Examination of the mechanism of the decolorization process by cell beads indicated that it proceeded primarily by biological decolorization associated with partial adsorption of the dye onto the entrapped cells and gel matrix. Microscopic observation revealed that the microbial consortium contained in the gel beads was at least made up of three kinds of bacterial species. From the economical viewpoint, alternative cheaper nitrogen sources such as fish meal, soybean meal, pharmamedia and vita yeast powder were examined.     

Time dependent degradation of mixture of structurally different azo and non azo dyes by using Galactomyces geotrichum MTCC 1360

Galactomyces geotrichum MTCC 1360, a yeast species showed 88% ADMI (American dye manufacturing institute) removal of mixture of structurally different dyes (Remazol red, Golden yellow HER, Rubine GFL, Scarlet RR, Methyl red, Brown 3 REL, Brilliant blue) (70 mg l⁻¹) within 24 h at 30 °C and pH 7.0 under shaking condition (120 rpm). Glucose (0.5%) as a carbon source was found to be more effective than other sources used. The medium with metal salt (CaCl₂, ZnSO₄, FeCl₃, MgCl₂, CuSO₄) (0.5 mM) showed less ADMI removal as compared to control, but did not inhibit complete decolorization. The presence of tyrosinase, NADH-DCIP reductase and induction in laccase activity during decolorization indicated their role in degradation. HPTLC (High performance thin layer chromatography) analysis revealed the removal of individual dyes at different time intervals from dye mixture, indicating preferential degradation of dyes. FTIR (Fourier transform infrared spectroscopy) and HPLC (High performance liquid chromatography) analysis of samples before and after decolorization confirmed the biotransformation of dye. The reduction of COD (Chemical oxygen demand) (69%), TOC (Total organic carbon) (43%), and phytotoxicity study indicated the conversion of complex dye molecules into simpler oxidizable products having less toxic nature.     

Decolorization and detoxification of Congo red and textile industry effluent by an isolated bacterium <Emphasis Type="Italic">Pseudomonas</Emphasis> sp. SU-EBT

The 16S rRNA sequence and biochemical characteristics revealed the isolated organism as Pseudomonas sp. SU-EBT. This strain showed 97 and 90% decolorization of a recalcitrant dye, Congo red (100 mg l⁻¹) and textile industry effluent with 50% reduction in COD within 12 and 60 h, respectively. The optimum pH and temperature for the decolorization was 8.0 and 40°C, respectively. Pseudomonas sp. SU-EBT was found to tolerate the dye concentration up to 1.0 g l⁻¹. Significant induction in the activity of intracellular laccase suggested its involvement in the decolorization of Congo red. The metabolites formed after decolorization of Congo red, such as p-dihydroxy biphenyl, 8-amino naphthol 3-sulfonic acid and 3-hydroperoxy 8-nitrosonaphthol were characterized using FTIR and GC–MS. Phytotoxicity study revealed nontoxic nature of the degradation metabolites to Sorghum bicolor, Vigna radiata, Lens culinaris and Oryza sativa plants as compared to Congo red and textile industry effluent. Pseudomonas sp. SU-EBT decolorized several individual textile dyes, dye mixtures and textile industry effluent, thus it is a useful strain for the development of effluent treatment methods in textile processing industries.     

Continuous Decolorization of Molasses Waste Water with Mycelia of Coriolus versicolor Ps4a

Continuous decolorization of molasses waste water by mycelia of Coriolus versicolor Ps4a was studied using waste water from a baker’s yeast factory, treated by means of methane fermentation and with activated sludge. Optimum decolorization with bare pellet-type mycelia in shaking flasks needed the addition of glucose (0.5%) and peptone (0.05%) and aerobic conditions (1ppm of dissolved oxygen). Continuous decolorization in a bubbling column reactor showed a decolorization yield of approximately 75% in only 20 hr at a dilution rate (D) of 0.03 hr^?1 under the optimum conditions.

In order to continue the decolorization for a longer time, mycelia immobilized within Caalginate gel were tested in a bubbling column reactor under the optimum conditions. The immobilized mycelia showed an almost constant decolorization yield (65.7%) during continuous decolorization for 16 days at D = 0.22 hr^?1.     

Bacterial decolorization of textile dyes is an extracellular process requiring a multicomponent electron transfer pathway

Many studies have reported microorganisms as efficient biocatalysts for colour removal of dye‐containing industrial wastewaters. We present the first comprehensive study to identify all molecular components involved in decolorization by bacterial cells. Mutants from the model organism Shewanella oneidensis MR‐1, generated by random transposon and targeted insertional mutagenesis, were screened for defects in decolorization of an oxazine and diazo dye. We demonstrate that decolorization is an extracellular reduction process requiring a multicomponent electron transfer pathway that consists of cytoplasmic membrane, periplasmic and outer membrane components. The presence of melanin, a redox‐active molecule excreted by S. oneidensis, was shown to enhance the dye reduction rates. Menaquinones and the cytochrome CymA are the crucial cytoplasmic membrane components of the pathway, which then branches off via a network of periplasmic cytochromes to three outer membrane cytochromes. The key proteins of this network are MtrA and OmcB in the periplasm and outer membrane respectively. A model of the complete dye reduction pathway is proposed in which the dye molecules are reduced by the outer membrane cytochromes either directly or indirectly via melanin.     

Decolorization and detoxication of reactive industrial dyes by immobilized fungi <Emphasis Type="Italic">Trametes pubescens</Emphasis> and <Emphasis Type="Italic">Pleurotus ostreatus</Emphasis>

Trametes pubescens and Pleurotus ostreatus, immobilized on polyurethane foam cubes in bioreactors, were used to decolorize three industrial and model dyes at concentrations of 200, 1000 and 2000 ppm. Five sequential cycles were run for each dye and fungus. The activity of laccase, Mn-dependent and independent peroxidases, lignin peroxidase, and aryl-alcohol oxidase were daily monitored during the cycles and the toxicity of media containing 1000 and 2000 ppm of each dye was assessed by the Lemna minor (duckweed) ecotoxicity test. Both fungi were able to efficiently decolorize all dyes even at the highest concentration, and the duckweed test showed a significant reduction (p 相似文献