Decolourization Of Synthetic Dyes Research Articles

SUSTAINABLE TECHNOLOGY FOR RECALCITRANT AZO DYES BY FUNGAL SPECIES ISOLATED FROM INDUSTRIAL EFFLUENT


 
 
 Synthetic dyes have a repugnant effect on the aquatic ecosystem and their venomous components have to be removed from the effluent before their exemption. The decolourization of synthetic dyes by fungi is emerging as an effective and clean technology. Fungal-abetted processes are amongst the finest approaches for transformation, degradation and decolourization of recalcitrant dyes. This study was carried out to find out the qualities of textile effluents with the estimation of physicochemical parameters of textile effluents, isolation and identification of fungi. The physicochemical parameters were demarcatedas per the standards prescribed by CPCB.15 fungi isolated from textile effluent and effluent- contaminated soil samples were evaluated to decolourize textile dyes - Reactive Red ME-4B and Brill blue-R. 9 different fungal species were further identified as Aspergillus spp, Penicillium spp, Mucor, Curvularia spp, Helmintho sporium spp, Fusarium spp, Trichoderma spp, Rhizopus, spp and Alternaria spp by 18S rRNA Sequencing. These 9 isolates with potential decolourization were assessed via primary and secondary decolourization. The study also showed that Penicillium spp, Aspergillus spp and Trichoderma spp are highly efficient in decolorizing (85.41, 98.80and83.23 %) in 6 days as used in the present investigation. The results have demonstrated the potential of the fungal isolates for the treatment of dyes contaminated textile effluent.
 
 

Thermo-active and alkaliphilic amalgamated laccase immobilized on sodium alginate for synthetic dye decolourization

Purified crude laccase of Enterobacter sp. Kamsi and Bacillus sp. NU2 in the hybrid and combined form was immobilized on sodium alginate beads and applied to decolourize various textile dyes through several decolourization reaction cycles. The enzyme/alginate (E/A) loading efficiency and immobilization yield were evaluated. The SEM-EDX analysis, pH, and temperature effects of both forms of immobilized laccases were examined. The maximum condition for Kamsi and NU2 laccases into Na-alginate beads is 2.5% (w/v), which resulted to >83 and 61.71% immobilization and loading efficiency, respectively. The SEM-EDX analysis showed a rough-spherical surface attributable to significant entrapment of the laccase at the centre of the beads. The hybrid laccase in the free and immobilized form showed >52% and 80% decolourization effects, while the amalgamated laccase showed >63 and 83% decolourizing effect on Malachite Green (MG), Remazol Brilliant Blue R (RBBR), Reactive Blue 4 (RB4), Congo Red (CR), and Methyl Orange (MO), respectively. The immobilized laccase retained >50 and 81% activity of the hybrid and amalgamated laccases, respectively, after six successive treatment cycles. The results showed that the immobilization technique of the Kamsi and NU2 laccase holds the potential for textile dye effluents degradation, but the amalgamation of an enzyme from different species could improve decolourization potentials for various dyestuff treatments.

Decolourization of synthetic dyes by laccase produced from Bacillus sp. NU2

Advanced industrialization has caused an increase in the continuous discharge of hazardous effluents in the environment. This study evaluated the potential of the laccase synthesized by Bacillus sp. NU2 to degrade five synthetic dyes. Sawdust, wheat bran and peels of banana and tangerine were utilized as carbon sources for bacterial growth and laccase production. The produced crude enzyme was purified to homogeneity to determine its molecular weight. The kinetic activity of the purified laccase was determined using 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). The toxicity of the laccase-treated dye solution was assessed on Bacillus sp. NU2 growth. The result showed optimum laccase yield from the tangerine peel medium. The purified laccase gave a specific activity of 349.94 U mg−1 and a molecular weight of 55 kDa, respectively. The purified laccase displayed a strong affinity for ABTS substrate with an enzyme activity of 31.21 U mg−1. It was optimum at 60 °C and pH 8, with catalytic efficiency (Kcat /Km ) of 23.93 mmol L−1. The decolourization effects on Congo Red, Methyl Orange, Remazol Brilliant Blue R, Reactive Blue 4 and Malachite Green were 87%, 70%, 65%, 63% and 51%, respectively. The toxicity assay of laccase degraded dyes on Bacillus sp. NU2 showed a growth reduction of 36.75% (Malachite Green), 12.57% (Congo Red), 17.19% (Methyl Orange), 38.41% (Remazol Brilliant Blue R) and 28.14% (Reactive Blue 4). The laccase produced by Bacillus sp. NU2 holds a high catalytic potential for the detoxification of dye effluents in an environmental system.

Enterobacter sp. AI1 produced a thermo-acidic-tolerant laccase with a high potential for textile dyes degradation

Biocatalytic decolourisation of synthetic dyes is hindered by the characteristic properties contained in the textile effluents. Cow dung was sampled from the University of Fort Hare farm, Eastern Cape Province, South Africa. The sample was subjected to selective enrichment, and the organism isolated was texted on various phenolic plates and quantitatively examined for laccase activities. The isolate was molecularly identified using 16S rRNA and subjected to extracellular laccase production. Agrowaste and time course were the factored optimised process conditions applied for laccase production. The laccase produced was purified and applied to degrade various synthetic dyes. The primary screening results showed various colour halo zone oxidation on the phenolic plate. The quantitative study gave a laccase activity of 54.71 and 38.21 (U/mL) on ABTS and PFC substrate molecularly identified as Enterobacter sp. AI1. Corn Stover (CS), Banana Peel (BP), and Wheat Bran (WB) optimally gave a laccase yield of 18.47, 18.87, 20.19 (U/mL) with a 12-day laccase yield of 38.25 U/mL. The purified laccase showed a specific activity of 187.88 U/mg of protein and a molecular weight of 75 kDa with a strong affinity for ABTS at 52.27 U/mL laccase activity. Laccase kinetic showed a Km and Vmax value of 0.23 and 51.28 and was optimum at pH4 and at 60 °C. The purified laccase maximally displayed decolourised effect of 78, 85.7, 77, 81, and 73 (%) on Malachite Green (MG), Congo Red (CR), Methyl Orange (MO), Remazol Brilliant Blue R (RBBR), and Reactive Blue 4 (RB4), respectively. The molecular identification Enterobacter sp. AI1 showed it belongs to the class of gammaproteobacterial. Their nucleotide sequence has been deposited in NCBI with the accession number MN686605. Conclusively, cow dung served as a rich source for isolating ligninolytic bacteria with active bioactive compounds applicable to bioprocess control.

Production of Fungal Laccase under Solid State Bioprocessing of Agroindustrial Waste and Its Application in Decolourization of Synthetic Dyes

Fungal laccases are preferred due to high redox potentials and low substrate specificity to xenobiotics including synthetic dyes. For large-scale applications, low enzyme yield and high cost of production has remained the challenge. Agroindustrial waste such as saw-dust of Terminalia superba abounds locally and was utilized as low-cost alternative substrate for laccase production in Solid State Bioprocessing (SSB) using Trametes sp. isolate G31. The study optimized laccase production using various parameters. Optimal production of laccase was at pH 5.0 - 7.0 with 2356 U/mL - 2369 U/mL and 25°C (2336 U/mL). Among the sources of nitrogen and carbon tested, laccase production in ammonium sulphate and sucrose supplemented media were higher. The effect of activators on laccases production showed that Cu2+ and Ca2+induced high titres of laccase at 4 -5 mM and 2 - 4 mM respectively, while production of laccase by Mn2+ was significantly high at 40 mM. The effect of 2, 2-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), guaiacol and varatryl alcohol on laccase production was significantly different especially in glycerol. Optimum production for laccase was on day 14 with 2356 U/mL followed by steady declined up to day 34. The purified laccase had a specific activity of 5008 µmol/min/mg, purification factor of 3.85, and a molecular mass of ~40 kDa using N-PAGE. The potential of crude laccase to decolourize diverse dyes was tested. Phenol red achieved 40% decolourization for 1hr, while RBBR (93%), Crystal violet (60%), Methylene blue (53%) and Congo red (51%) for 24 hr, 72 hr, 48 hr and 120 hr respectively. Methyl red and Malachite green attained 42% (72 hr) and 32% (48 hr) decolourization. The enzyme ability to oxidize Phenol red and other synthetic dyes without mediators made it eco-friendly in treating dye wastewaters.

Lignolytic mushroom Lenzites elegans WDP2: Laccase production, characterization, and bioremediation of synthetic dyes

A mycoremedial study was undertaken for decolourization of synthetic dyes using wood rot fungal culture Lenzites elegans WDP2. The culture was isolated from decaying wood as fruiting body, and identified on the basis of 5.8S ITS rRNA gene sequence analysis. Qualitative plate screening of culture showed extracellular laccase and lignin peroxidase production, while only laccase enzyme was produced in higher amount (156.793 Uml−1) in minimal salt broth medium containing glucose and veratryl alcohol. Laccase activity was increased up to 189.25 Uml−1 after optimization of laccase production by optimization of one variable at a time approach. Molecular characterization of laccase enzyme was done using SDS PAGE and Native PAGE based isozyme analyses. The culture was able to decolorize three synthetic dying compounds (congo red, Malachite green and brilliant green) in broth media, while showed very less decolourization in plate assay. The fungal culture varied in their dye decolourizing potential in broth culture, showing 92.77%, 21.27% and 98.8% maximum decolourization of brilliant green, malachite green and congo red respectively. The congo red dye was completely bio-absorbed by fungal culture within one month. The fungal decolourized broth also revealed the extracellular laccase activity; varied from 10 Uml−1 to 68.5 Uml−1 in all the three cases, supports the involvement of laccase enzyme in decolorization. Phase contrast microscopy clearly revealed bio-sorption of the dyes by fungal culture into the mycelium/spores in the photomicrographs.

Preparation and Optimisation of Cross-Linked Enzyme Aggregates Using Native Isolate White Rot Fungi Trametes versicolor and Fomes fomentarius for the Decolourisation of Synthetic Dyes.

The key to obtaining an optimum performance of an enzyme is often a question of devising a suitable enzyme and optimisation of conditions for its immobilization. In this study, laccases from the native isolates of white rot fungi Fomes fomentarius and/or Trametes versicolor, obtained from Czech forests, were used. From these, cross-linked enzyme aggregates (CLEA) were prepared and characterised when the experimental conditions were optimized. Based on the optimization steps, saturated ammonium sulphate solution (75 wt.%) was used as the precipitating agent, and different concentrations of glutaraldehyde as a cross-linking agent were investigated. CLEA aggregates formed under the optimal conditions showed higher catalytic efficiency and stabilities (thermal, pH, and storage, against denaturation) as well as high reusability compared to free laccase for both fungal strains. The best concentration of glutaraldehyde seemed to be 50 mM and higher efficiency of cross-linking was observed at a low temperature 4 °C. An insignificant increase in optimum pH for CLEA laccases with respect to free laccases for both fungi was observed. The results show that the optimum temperature for both free laccase and CLEA laccase was 35 °C for T. versicolor and 30 °C for F. fomentarius. The CLEAs retained 80% of their initial activity for Trametes and 74% for Fomes after 70 days of cultivation. Prepared cross-linked enzyme aggregates were also investigated for their decolourisation activity on malachite green, bromothymol blue, and methyl red dyes. Immobilised CLEA laccase from Trametes versicolor showed 95% decolourisation potential and CLEA from Fomes fomentarius demonstrated 90% decolourisation efficiency within 10 h for all dyes used. These results suggest that these CLEAs have promising potential in dye decolourisation.

Effects of Waste Pisum Sativum Pod Adsorbent Size and Dose on Efficiency of Decolourization of Synthetic Dyes

Effects of Waste Pisum Sativum Pod Adsorbent Size and Dose on Efficiency of Decolourization of Synthetic Dyes

Lenzites elegans KSG32: A Novel White Rot Fungus for Synthetic Dye Decolourization

Lenzites elegans KSG32: A Novel White Rot Fungus for Synthetic Dye Decolourization

Application of Immobilized Laccase from Bacillus subtilis MTCC 2414 on Decolourization of Synthetic Dyes

Application of Immobilized Laccase from Bacillus subtilis MTCC 2414 on Decolourization of Synthetic Dyes

Decolourisation of Synthetic Dyes by Endophytic Fungal Flora Isolated from Senduduk Plant (Melastoma malabathricum).

A total of twenty endophytic fungi successfully isolated from Melastoma malabathricum (Senduduk) were examined for their ability to decolourise azo dyes: Congo red, Orange G, and Methyl red and an anthraquinone dye, Remazol Brilliant Blue R. Initial screening on the glucose minimal media agar plates amended with 200 mg L−1 of each respective dye showed that only isolate MS8 was able to decolourise all of the four dyes. The isolate decolourised completely both the RBBR and Orange G in the agar medium within 8 days. Further quantitative analysis of the dye decolourisation by isolate MS8 in aqueous minimal medium showed that isolate MS8 was able to decolourise all the tested dyes at varying levels. Dye decolourisation by the isolate MS8 was determined to be 97% for RBBR, 33% for Orange G, 48% for Congo red, and 56% for Methyl red, respectively, within a period of 16 days. Molecular identification of the fungal isolate MS8 using primer ITS1 and ITS4 showed that isolate MS8 shared 99% sequence similarity with Marasmius cladophyllus, a Basidiomycete. The ability to decolourise different types of dyes by isolate MS8 thus suggested a possible application of this fungus in the decolourisation of dyestuff effluents.

Microbial decolourization of textile waste water

Six fungal isolates belong to Aspergillus niger, Penicillium spp., and Pleurotus osstreatus were used for decolourization activities of some acid and reactive dyes, after they screened for optimum efficiency and the condition for temperature and pH were optimized The results obtained indicated that Pleurotus osstreatus and Aspergillus niger 1 and 2 are more efficient than Penicillium spp., with the two kinds of dyes used. The results also revealed that, the maximum degradation activities of these isolates for acid dyes was at pH 5 after 9 days incubation period and at pH 5-6, for reactive dyes. Simulated and actual waste water samples were used in the experiments. Fungi decolourization of synthetic dyes according to their life state group 1: (living cells) to biodegradation and biosorb dyes. The major mechanism is biodegradation because they can produce the lignin modifying enzymes, lactose, manganese peroxides (Lip) to mineralize synthetic lignin of dyes. Group 2: dead cells (Fungal biomass) to adsorb dyes.

Synthetic dye decolourization, textile dye and paper industrial effluent treatment using white rot fungi Lentines edodes

The laccase producing fungi Lentines edodes was screened for laccase production using various indicator compounds like guaiacol, tannic acid and the polymeric dyes such as Remazol brilliant blue R and Poly R-478. The organism Lentines edodes that produce laccase was cultivated on basal medium. Potato dextrose agar medium (PDA) and malt extract agar medium (MEA) were used for the first subculture of chosen isolate and the plates were examined by light microscopy to check the absence of bacteria and the unique fungi isolation. For testing the crude enzyme laccase activity an agar plug (1 cm 2 ) from a 7-day old Lentines edodes agar plate was transferred to 50 ml of potato dextrose broth in Erlenmeyer flasks. The cultures were maintained at 25°C for 7 days. Screening was performed in Petri dishes (60 mm diameter) with 15 ml of malt extract agar (MEA) medium and potato dextrose agar (PDA) medium from Hi media, Mumbai, India, containing indicator compounds such as 0.04% (w/v) of Remazol Brilliant Blue-R (RBBR) and Poly R-478, 0.01% (v/v) of guaiacol and tannic acid 0.05% (w/v). Guaiacol (Sigma) RBBR (Sigma) and Poly R-478 (Sigma) were added to the media after autoclaving as sterile-filtered solutions. Tannic acid (Merck Chemicals Ltd., UK) was autoclaved separately before addition to the media. Guaiacol is a sensitive substrate that allows a rapid screening of fungal strains producing extracellular guaiacol oxidizing enzymes by means of a colour reaction. The white-rot fungus Trametes hirsuta that produces laccase, manganese peroxidase and lignin peroxidase was used as a positive control. The identity of laccase producing fungal species was confirmed by brown color development surrounding the fungal growth. Any colony produce yellow or which causes decolourization of Poly R-478 was considered as ligninolytic positive and isolated. Decolourization of Poly R 478, RBBR, guaiacol and tannic acid oxidizing strains were also studied on liquid cultures for lignin peroxidase, manganese peroxidase and laccase activities. For laccase activity, the isolated fungi was grown at 25°C for 12 days with rotary shaking (150 rpm) in 500-ml baffled Erlenmeyer flasks containing 50 ml of potato dextrose broth. The crude extract of Lentines edodes revealed promising results on decolourization of various dye stuffs, paper and textile effluents. About 74.1% of reactive yellow, 77.5% reactive blue and 75% RBBR dye stuffs were effectively decolorized on the third day. Similarly, more than 90% of textile and paper effluents were decolorized on first day itself.

Production and synthetic dyes decolourization capacity of a recombinant laccase from Pichia pastoris

To produce and purify a recombinant laccase from Pichia pastoris and to test its ability in decolourization of synthetic dyes. A cDNA encoding for a laccase was isolated from Pycnoporus sanguineus and was expressed in P. pastoris strain SMD1168H under the control of the alcohol oxidase (AOX1) promoter. The laccase native signal peptide efficiently directed the secretion of the recombinant laccase in an active form. Factors influencing laccase expression, such as cultivation temperature, pH, copper concentration and methanol concentration, were investigated. The recombinant enzyme was purified to electrophoretic homogeneity, and was estimated to have a molecular mass of about 62.8 kDa. The purified enzyme showed a similar behaviour to the native laccase produced by P. sanguineus. Four different synthetic dyes including azo, anthraquinone, triphenylmethane and indigo dyes could be efficiently decolourized by the purified recombinant laccase without the addition of redox mediators. Heterologous production of P. sanguineus laccase in P. pastoris was successfully achieved. The purified recombinant laccase could efficiently decolourize synthetic dyes in the absence of mediators. This study is the first report on the synthetic dye decolourization by the recombinant P. sanguineus laccase. The decolourization capacity of this recombinant enzyme suggested that it could be a useful biocatalyst for the treatment of dye-containing effluents.

Purification and characterization of the laccase secreted by the white rot fungus Perenniporia tephropora and its role in the decolourization of synthetic dyes

To characterize the white rot fungus Perenniporia tephropora with respect to its laccase and to test its ability to decolourize synthetic dyes. Under the culture conditions utilized, P. tephropora produced one laccase isozyme, which was purified to electrophoretic homogeneity by ammonium sulfate precipitation, size-exclusion chromatography and anion-exchange chromatography. The protein was monomeric with a molecular mass of 63 kDa (SDS-PAGE) and had an isoelectric point of 3.3. The N-terminal amino acid sequence was SIGPVADLTVTNANI and the highest similarity value was found to the laccase from Lentinus tigrinus (86.6%). The optimum pH of the enzyme varied and was substrate dependent. It was 4.0 and 5.0 for 2,6-dimethoxyphenol (DMP) and 2,2'-azino-di(3-ethyl-benzthiazoline-6-sulfonate) (ABTS), respectively. Under standard assay conditions, K(m) values of the enzyme were 7.3 and 0.4 mmol l(-1) towards DMP and ABTS, respectively. The laccase was inhibited by NaN(3), EDTA and p-coumarate but not by SDS and NaBr. Laccase was stable in the presence of some metal ions such as Cu(2+), Co(2+), Ca(2+), Cd(2+), Mg(2+), Mn(2+), Mo(2+), Ni(2+), Li(+) and Al(3+). The crude enzyme as well as the purified laccase was able to decolourize dyes from the textile industries, including remazol brilliant blue R, neolane blue and neolane pink. However, several other dyes were partially or not decolourized. In the presence of 1-hydroxybenzotriazole as mediator, only the decolourization of neolane yellow was achieved, while the decolourization of most of the dyes was just slightly improved. This study is the first report on the purification and the characterization of the laccase from the white rot fungus P. tephropora. The high levels of laccase secreted by this fungal strain as well as its stability suggest that it could be a useful tool for environmental applications.

Use of Phanerochaete chrysosporium Immobilized on Kissiris for Synthetic Dye Decolourization: Involvement of Manganese Peroxidase

The mineral Kissiris, which is formed from the thickened foam of volcanic lava, was tested to approximate its mineral composition using energy-dispersive X-ray (EDX) analysis. The solid mineral contains silicon dioxide at about 16 (w/w). The considerable surface roughness of Kissiris along with its extensive porosity made this natural solid cell support an attractive candidate for manganese peroxidase (MnP) production for synthetic dye decolourization, at low cost. The white rot fungus Phanerochaete chrysosporium immobilized on the mineral Kissiris was grown in both stationary and agitated cultures (rotary shaker, 100 rev/min) using either carbon- or nitrogen-limited growth medium to study the ability of the fungus to degrade the synthetic dye methylene blue (MB). The value of residual dye for MB used at 60 ppm was 6% within 8 days of the incubation of the nitrogen-limited culture under the shaken conditions. Production of (MnP) occurred simultaneously in nitrogen-limited culture medium with the added MnSO4 at 100 ppm. The MnP activity was at relatively high level (170 U/l).

Decolourization of synthetic dyes by Trametes hirsuta in expanded-bed reactors

The present paper studies the decolourization of different synthetic dyes (Indigo Carmine, Bromophenol Blue, Methyl Orange and Poly R-478) by the white-rot fungus Trametes hirsuta at bioreactor scale under solid-state conditions, operating with ground orange peelings as a support-substrate. Dye decolourization was performed in both batch and continuous mode. Batch cultivation led to high decolourization percentages in a short time (100% for Indigo Carmine in 3 h and 85% for Bromophenol Blue in 7 h). As for continuous cultivation, different hydraulic retention times (HRT) were studied (0.8, 1, 1.5 and 3 d). The highest decolourization percentages were obtained operating at a HRT of 3 d, especially for the dyes Methyl Orange and Poly R-478 (81.4% and 46.9%, respectively). This is a very interesting result, since there are few studies dealing with the continuous decolourization of dyes at bioreactor scale by fungal laccases.

Fungal Bioreactors: Applications to White-Rot Fungi

The growth mechanisms of filamentous fungi in liquid cultures ranges from dispersed mycelia to compact pellets. The excessive growth of mycelia gives rise to practical and technical difficulties in culturing fungi and consequently the possibility to control and regulate hyphal extension and pellet size is of great importance for their potential application in continuous operation. Here we show how the control of fungal growth on the surface of a biofilm by means of a pulsing flow can enhance the efficiency and stability of processes with different objectives, i.e., the production of a ligninolytic enzyme, the decolourisation of synthetic dyes and the detoxification of coloured effluents.

Decolourization of synthetic dyes by a newly isolated strain of Serratia marcescens

A novel dye-decolourizing strain of the bacterium Serratia marcescens efficiently decolourized two chemically different dyes Ranocid Fast Blue (RFB) and Procion Brilliant Blue-H-GR (PBB-HGR) belonging respectively to the azo and anthraquinone groups. Extracellular laccase and manganese peroxidase (MnP) activity were detected during dye decolourization. The involvement of MnP activity was found in the decolourization of both dyes. More than 90% decolourization of PBB-HGR and RFB was obtained on days 8 and 5, respectively at 26 °C under static conditions at pH 7.0. MnP activity was increased by the addition of Mn2+ · At 50 μM Mn2+, high MnP (55.3 U/ml) but low laccase activity (8.3 U/ml) was observed. Influence of oxalic acid on MnP activity was also observed.

Evaluation of different fungal strains in the decolourisation of synthetic dyes

Of seven fungal strains tested for their ability to decolourise three structurally diverse synthetic dyes, Phanerochaete sordida, Bjerkandera sp. BOS55, Phlebia radiata, and Phanerochaete chrysosporium had average values of maximum decolourisation rates higher than 0.2 Δ[Absorbance] d−1. All seven fungi produced manganese peroxidase (MnP) but laccase activity was detected only in Phlebia radiata. No lignin peroxidase (LiP) activity was observed.