Dye Decolorization Research Articles

Microemulsion Templating Synthesis of Hierarchical Porous Ag‐Doped SiO2‐TiO2 Composites for Efficient Degradation of Noxious Methylene Blue Dye: Effect of Calcination Environment

AbstractWe report herein a dual function mesoporous structure of titanium oxide based porous carbon with large surface‐to‐volume ratios for efficient degradation of noxious methylene blue dye (MB) from an aqueous environment. The mesoporous photocatalysts is fabricated via direct template synthesis of highly ordered silica‐titania monolith doped with Ag0/Ag2O starting from a quaternary microemulsion liquid crystalline phase. The produced monoliths are subjected in‐situ to doping by growing silver, in the cubic cavities, and on the silica/titania structure's domain. This study investigated the efficiency of novel composite materials, consisting of silver‐doped silica‐titania (SiO2/TiO2), which is synthesized using the microemulsion templating approach. The photocatalytic performance of the synthesized composite in the photodegradation of MB has been studied. The procedure of photodegradation was employed to achieve decolorization of the cationic MB dye using visible light. The catalyst effectively achieved the decolorization of the dyed solution through the processes of adsorption and photodegradation. The composite consisting of SiO2, TiO2, and Ag2O at a ratio of 1 : 1:0.5, which underwent calcination in an air environment (AgOST), exhibited a removal efficiency of 99 % compared to its calcined state under argon (AgSTC).

In-situ biosynthesis of metallic nanoparticles using Allium sativum and Chondrilla juncea extract: characterization and application in dye decolorization

The synthesis of catalysts has gained specific concern due to their versatile applications in particular azo dye decolorization. In the current work, metallic nanoparticles (copper and silver) were In-situ biosynthesised using Allium sativum and Chondrilla juncea extract. The obtained Allium-copper oxide and Allium-silver oxide materials were analyzed using SEM, TEM, FT-IR, TGA-DTG, SEM, TEM, and XRD techniques. Allium peels had a rough surface, with nanoparticles equally distributed over it. The crystal structure of Allium peels was altered after the addition of CuO and AgO nanoparticles. The highest residual mass values in the prepared materials indicated that the metallic nanoparticles were, in situ, formed. The prepared materials had worse thermal stability than Allium peel powders. The azo dyes, Calmagite and Naphthol Blue Black B were tested in the catalytic power of the resulting materials. The decolorization process was affected by the dye structure, amount of H2O2, dye concentration, time of reaction, and temperature of the bath. The activation energy values for Allium-CuO were 18.44 kJ mol−1 for calmagite, and 23.28 kJ mol−1 for naphthol blue black, respectively. Nevertheless, the energy values for Allium-AgO were 50.01 kJ mol−1 for calmagite and 12.44 kJ mol−1 for Naphthol blue black. The calculated low energy values for the prepared materials suggested the high efficiency of the use of these catalysts in azo dye decolorization under the change of some main experimental conditions.

Ultrasound-Assisted Advanced Oxidation Process Using Perovskite-Type LaMnO3 Nanospheres.

Among the perovskite oxide community, La-based perovskites have garnered considerable interest due to their remarkable properties including catalytic, electrocatalytic, photocatalytic, sensing, electrical, magnetic, and optical characteristics. Herein, rhodamine-B (RB) dye has been reported to be sono-catalytically decomposed by an ultrasound-assisted advanced oxidation process (AOP) using perovskite-type LaMnO3 (LMO) nanospheres synthesized via ultrasonic approach. Several physiochemical characterizations such as XRD, FT-IR, XPS, SEM, TEM, and SEM-EDS investigations were used to investigate the LMO perovskite nanospheres. Then, LMO potential for adsorption and the sonocatalytic decolorization of RB dye in an aqueous solution are examined. With LMO perovskites, the adsorption and removal kinetics of RB correspond to the pseudo-first-order model. Furthermore, by utilizing the pseudo-first-order, the RB dye process is removed with improved efficacy in the following sequence: Agitation alone: 3.76×10-4 min-1<US only: 5.02×10-3 min-1<LMO only: 5.85×10-3 min-1<LO@MO + US: 1.38×10-2 min-1<LMO + US: 1.75×10-2 min-1, accordingly. Perovskite-type LMO, which has significant reusability and stability, is an ensuring sonocatalyst for dye decomposition in wastewater, enabling faster decolorization. A prospective mechanism has been suggested for the sonocatalytic decomposition of RB.

Enhanced bioremediation of saline azo dye effluents using PersiLac3: A thermo-halotolerant laccase from a tannery metagenome

Large quantities of recalcitrant azo dye wastewater represent an important environmental issue, owing to their toxicity and the difficulty of their treatment under hypersaline conditions. By maintaining high activity under salt-rich conditions, salt-tolerant laccases offer a promising solution for the effective breakdown of toxic azo dyes, making them indispensable for the sustainable treatment of industrial wastewater. This study explored the identification and application of a thermo-halotolerant laccase, PersiLac3, for bioremediation of azo dye wastewater under high-salt conditions typical of textile effluents. The broad substrate oxidation potential of PersiLac3 was assessed across diverse temperatures, pH levels, and challenging conditions, such as high salt levels, and in the presence of organic solvents and inhibitors. Remarkably, PersiLac3 showed enhanced activity (112.25 %) in 3 M NaCl, highlighting its superior ability to adapt to saline conditions. Kinetic studies of PersiLac3 indicated high efficiency and affinity for its substrate at saline concentrations ranging from 1 to 6 M NaCl. PersiLac3 effectively decolorized the Congo red dye (82.9 %) in highly concentrated solutions (5000 mg/L) within 15 min, and its performance was further improved in the presence of wastewater-relevant ions, achieving 92.3 % dye removal. Monitoring real wastewater treatments, PersiLac3 reduced optical density, underscoring its potential for application in the bioremediation of dye-laden and saline wastewater streams. The adaptability of PersiLac3 to harsh, high-salinity environments, coupled with its rapid dye decolorization efficiency, is an innovative and powerful tool for addressing environmental pollution challenges and advancing waste treatment methodologies.

Optimization, purification and characterization of laccase from a new endophytic Trichoderma harzianum AUMC14897 isolated from Opuntia ficus-indica and its applications in dye decolorization and wastewater treatment.

Hazardous synthetic dye wastes have become a growing threat to the environment and public health. Fungal enzymes are eco-friendly, compatible and cost-effective approachfor diversity of applications. Therefore, this study aimed to screen, optimize fermentation conditions, and characterize laccase from fungal endophyte with elucidating its ability to decolorize several wastewater dyes. A new fungal endophyte capable of laccase-producing was firstly isolated from cladodes of Opuntia ficus-indica and identified as T. harzianum AUMC14897 using ITS-rRNA sequencing analysis. Furthermore, the response surface methodology (RSM) was utilized to optimize several fermentation parameters that increase laccase production. The isolated laccase was purified to 13.79-fold. GFC, SDS-PAGE revealed laccase molecular weight at 72kDa and zymogram analysis elucidated a single band without any isozymes. The peak activity of the pure laccase was detected at 50°C, pH 4.5, with thermal stability up to 50°C and half life span for 4h even after 24h retained 30% of its activity. The Km and Vmax values were 0.1mM, 22.22µmol/min and activation energy (Ea) equal to 5.71kcal/mol. Furthermore, the purified laccase effectively decolorized various synthetic and real wastewater dyes. Subsequently, the new endophytic strain produces high laccase activity that possesses a unique characteristic, it could be an appealing candidate for both environmental and industrial applications.

Site-Directed Mutagenesis of Two-Domain Laccase ScaSL for Obtaining a Biocatalyst with Improved Characteristics

Analysis of the structure of two-domain laccase ScaSL from Streptomyces carpinensis VKM Ac-1300 (with a middle-redox potential) revealed determinants that could affect the increased potential of ScaSL. Site-directed mutagenesis of the ScaSL laccase was carried out, and mutants H286A, H286T, H286W, and F232Y/F233Y were obtained. Replacement of His 286 with Ala led to a decrease in redox potential (0.45 V) and an increase in stability at pH 9 and 11; replacement with Thr led to an increase in redox potential (0.51 V) but to a decrease in the thermal stability of the protein; replacement with Trp did not affect the enzyme properties. Replacement of Phe residues 232 and 233 with Tyr led to a shift in enzyme activity to the acidic pH range without changing the redox potential and a decrease in the thermostability and pH stability of the enzyme. All mutants more efficiently oxidized phenolic substrate 2,6-DMP and were able to participate in direct electron transfer (DET) with MWCNT-modified electrodes. The F232Y/F233/Y mutant was unable to degrade triphenylmethane dyes without a mediator but showed a greater degree of decolorization of azo dyes in the presence of the mediator. The crystal structure of laccase with the highest potential was determined with high resolution.

Development of the novel advanced electrooxidation process for decolorization of recalcitrant dyes (Methylene Blue, Rhodamine B, Congo Red): Effect of operating factors

The research aims to develop an advanced electrooxidation process for decolorization of recalcitrant dye. To enhance the radical formation, a combination of UV irradiation and electrooxidation (UV/EO) is used. Methylene Blue (MB), Rhodamine B (RB) and Congo Red (CR) dyes were used as model compounds to represent recalcitrant dyes. The performance of UV/EO process was investigated under various operating factors (i.e., current density (CD), voltage, pH, NaCl, anodic material), and compared with chlorination, UV irradiation, and electrooxidation (EO) process. MB was the highest resistant dye to the UV/EO process. The UV/EO process exhibited a synergistic effect on decolorization, and it removed MB 1.35 time faster than the EO process. Based on indirect determination of •OH, the •OH formation in the EO process was 2.4 ×10−13 M, which lower than that in the UV/EO process by 4 times. The second-order rate constant for MB oxidation by HO• (kHO•,MB) was 3.31 × 109 M−1s−1. The pseudo 1st-order decolorization kinetic (k’) was independent with voltages, but directly depended on CD and NaCl concentrations. Lower pH enhanced the k’ value. The specific energy consumption was in a range of 0.408 – 5.303 kWh/m3, depending on the k’ value. The energy consumption decreased with higher the k’ value, except for increasing CD. The Boron Doped Diamond (BDD) was more effective in the decolorization rate than dimensional active anode (DSA) by 1.6 times. Treatment of industrial dye wastewater by the UV/EO process eliminated color intensity (ADMI), COD, and BOD5 by 80 %, 91 %, and 9 %, respectively.

Efficient biodecolorization of direct black 22 Azo Dye by Aspergillus tamarii Kita UCP1279 isolated from caatinga soil

The textile industry is a major consumer of water, generating large volumes of wastewater contaminated with harmful substances, particularly azo dyes, which contain aromatic rings, amines, and sulfonic groups that contribute to their environmental toxicity. The use of microbial agents for wastewater treatment offers a cost-effective and sustainable solution, minimizing sludge production. Fungi from the Caatinga biome have demonstrated potential for bioremediation, especially under extreme environmental conditions. This study explores the ability of Aspergillus tamarii Kita to decolorize the azo dye Direct Black 22 (DB22) under varying conditions, including the use of both active and inactive fungal biomass, in static and agitated systems (120 rpm), at a controlled temperature of 30°C. Dye concentrations of 50, 125, and 250 mg/L were evaluated over time intervals of 75, 180, and 180 minutes, respectively. The influence of dissolved oxygen concentration and redox potential on the decolorization process was also investigated to identify optimal treatment conditions. Decolorization efficiency was quantified via spectrophotometric analysis. Results revealed decolorization rates of 100%, 97%, and 63% for the respective dye concentrations, with active biomass in agitated conditions achieving the highest removal rates. The study further demonstrated that dissolved oxygen levels and redox potential are critical factors in enhancing dye decolorization. These findings underscore the bioremediation potential of Aspergillus tamarii Kita in treating textile dye effluents, offering a promising approach to sustainable industrial wastewater management.

Evaluation of blue textile dye decolorization by immobilized polyphenol oxidase using pumice stone under optimum conditions

Industrial dyes are major pollutants in wastewater and river water with an initial visible concentration of 1 mg/L. Recent studies have shown the possibility of using polyphenol oxidase in catalytic biological treatment due to its ability to oxidize a large number of dyes and pollutants in wastewater and the flexibility to work in wide ranges of temperature, pH and salinity. It is easy availability as well as the low economic cost resulting from its use in biological treatments, this enzyme polyphenol oxidase was used. The findings in this study showed that the extraction of polyphenol oxidase (PPO) from potato peel was homogenized with potassium phosphate buffer (0.1 M, pH 7) at a ratio of 1:10 (weight: volume) for two min. The result of enzyme purification by ion exchange chromatography showed that the yield of this step was 64 % and the specific activity was 6541.67 U/mg. The polyphenol oxidase was immobilized covalently on the functionalized pumice stone (25.2 U/gm) compared with other methods. The characterization results demonstrated that the optimum pH for immobilized and free enzyme activity was 6.0 while the pH range of free and immobilized polyphenol oxidase stability was from 4.5 -7.0 and 3.5 - 8.5 respectively. The better temperature for free and immobilized polyphenol oxidase activity was 25 ºC, whereas the free and immobilized polyphenol oxidase was stable at 15-35 and 15-50 °C respectively. The outcomes showed that the decolorization efficiency of blue textile dye employing immobilized polyphenol oxidase reached 99.85 % after 24 hr. for 100 mg/L concentration while for other concentrations 200, 300, 400, 500 and 1000 mg/L the decolorization efficiencies were 85.96, 76.15, 72.54, 66.94 and 63.5 % respectively. Based on the results, the immobilized polyphenol oxidase on pumice stone is highly efficient in removing textile dyes at large concentrations and in different environmental conditions.

Interaction between the electrochemical properties of powdered activated carbon and the biochemical processes within bacteria in Azo dye biodecolorization: An explanatory mechanism

Drawing on prior reports highlighting the redox mediator properties of powdered activated carbon (PAC), this study was designed to evaluate these properties to enhance the decolorization of azo dye by Klebsiella quasipneumoniae GT7. It was found that the presence of 0.5 % PAC in the medium increased the biodecolorization rate early in incubation. Chemical analysis revealed that dye conversion into aromatic amines occurred in microbial systems both with and without PAC. However, at initial dye concentrations (Cid) of 2 mM or higher, some dye remained on the PAC surface and in the medium. In contrast, the PAC-free system achieved nearly 100 % biodecolorization at all initial dye concentrations. The negative impact of PAC on decolorization efficiency in microbial systems with high initial dye concentrations cannot be solely explained by its redox mediator function. This study used the amphoteric-Donnan model for PAC's electrical double layer (EDL) and Mitchell's chemiosmotic model for bacterial proton motive force (PMF) to explore this. It found that charge storage in PAC's EDL regulates electron transfer fluxes, and proton species enhance the proton motive force across the bacterial membrane. These observations improve the understanding of PAC's role in microbial decolorization and its potential future applications.

Therapeutic Applications of Azo Dye Reduction: Insights From Methyl Orange Degradation for Biomedical Innovations.

This paper emphasizes the possible application of methyl orange reduction as a therapeutic technique, highlighting the potential of azo dye reduction in biomedical fields. The generally used azo dyes are toxic and carcinogenic; hence, they implicitly threaten the environment and health. The degradation of methyl orange, a famous example of azo dyes, is used to describe the degradation process for other azo dyes. This work discusses the ability of different methyl orange degradation methods, focusing on biocatalysts and nanomaterials, among the methods that identified enzymatic degradation with azoreductase enzymes as the method that quickly breaks down azo dyes under mild conditions as the most appropriate method, as well as its specificity as environmentally friendly. Moreover, metal nanoparticles such as silver and gold impellers increase the reducing efficiency because they offer a pivotal surface for the reduction reactions that undergo electron transfer. The complete breakdown of methyl orange is essential in biomedical usage. The strategies for treating azo dye reduction can be extended to next-generation drug delivery systems (DDS), biosensors, and therapeutic agents. Organisms involved in degradation can be functionalized to selectively degrade specific cells or tissues, thus presenting a new targeted therapy. Knowledge of degradation pathways and non-toxic products is essential in creating programs that build better and more efficient therapeutic agents. This work endeavors to illustrate the development of enzymatic and nanomaterials-based approaches to achieve sustainable azo dye decolorisation to open the gateway to developing other biomedical applications that tend to promote environmental and health-friendly solutions.

Biodecolorization of Azo Dye by Bacteria Alcaligenes faecalis Sub Sp. Phenolicus Isolated from a Bark-Beetle Tunnel Developed in Peltophorum Pterocarpum Plant

This study assessed the decolorization of reactive red 120 (RR120) by Alcaligenes faecalis subsp. phenolicus strain isolated from the bark borer insect (Indarbela tetraonis) tunnel developed in Peltophorum pterocarpum. The optimal parameters for the dye of decolorization 0.1 mg/L of dye were pH 7, temperature 35°C, fructose (0.4% w/v) as the carbon supply (0.4% w/v), peptone (0.2% w/v) as the nitrogen source (0.4% w/v), 12 hours of static conditions, and 0.3 ml of inoculums. Cell suspension, sodium alginate (3%, w/v), and PVA (5%, w/v) immobilized cell beads (10 beads 0.5 mm in size) were used in the batch continuous reactor for complete bio-decolorization of RR120. The batch reactor was subjected to 5 cycles of batches for 3 days of constant use. Under optimal conditions, the batch mode achieved more than 99% dye decolorization and fabric color removal in less than 48 hours of contact. When the control and dye-decolorized media were analyzed using UV spectroscopy, the absorbance of the control medium was higher than that of the decolorized media. GC-MS and FTIR analysis revealed the basic compounds and functional groups of the parent RR120 dye. This strain decolored 76.51% of AB 113, 96.8% of orange II, 98.47% of congo red, 98.3% of RR120, 97.92% of phenol red individual dyes, and 94.72% of the dye mixture at 12 hours. A. faecalis subsp. Phenolicus strains produced positive results in the qualitative analytical test of exopolysaccharides (EPS) and plant growth-promoting rhizobacteria (PGPR) production. The RR120 was decolorized in the presence of heavy metal ions by A. faecalis sub-sp. Phenolicus bacteria.

Enhancing Laccase Production by Trametes hirsuta GMA-01 Using Response Surface Methodology and Orange Waste: A Novel Breakthrough in Sugarcane Bagasse Saccharification and Synthetic Dye Decolorization

Trametes hirsuta GMA-01 was cultivated in a culture medium supplemented with orange waste, starch, wheat bran, yeast extract, and salts. The fungus produced several holoenzymes, but the laccase levels were surprisingly high. Given the highlighted applicability of laccases in various biotechnological areas with minimal environmental impact, we provided a strategy to increase its production using response surface methodology. The immobilization of laccase into ionic supports (CM-cellulose, DEAE-agarose, DEAE-cellulose, DEAE-Sephacel, MANAE-agarose, MANAE-cellulose, and PEI-agarose) was found to be efficient and recuperative, showcasing the technical prowess of research. The crude extract laccase (CE) and CM-cellulose-immobilized crude extract (ICE) showed optimum activity in acidic conditions (pH 3.0) and at 70 °C for the CE and 60 °C for the ICE. The ICE significantly increased thermostability at 60 °C for the crude extract, which retained 21.6% residual activity after 240 min. The CE and ICE were successfully applied to sugarcane bagasse hydrolysis, showing 13.83 ± 0.02 µmol mL−1 reducing sugars after 48 h. Furthermore, the CE was tested for dye decolorization, achieving 96.6%, 71.9%, and 70.8% decolorization for bromocresol green, bromophenol blue, and orcein, respectively (0.05% (w/v) concentration). The properties and versatility of T. hirsuta GMA-01 laccase in different biotechnological purposes are interesting and notable, opening several potential applications and providing valuable insights into the future of biotechnological development.

Optimization of the Decolorization of Triphenylmethane Dyes by Bacterial Monoculture and Consortium Screened from Textile Wastewater

Optimization of the Decolorization of Triphenylmethane Dyes by Bacterial Monoculture and Consortium Screened from Textile Wastewater

The application and assessment of bacterial isolates for textile dye decolorization

The application and assessment of bacterial isolates for textile dye decolorization

Synchronous reinforcement azo dyes decolorization and anaerobic granular sludge stability by Fe, N co-modified biochar: enhancement based on extracellular electron transfer

Anaerobic digestion (AD) treatment of azo dyes wastewater often suffers from low decolorization efficiency and poor stability of anaerobic granular sludge (AnGS). In this study, iron and nitrogen co-modified biochar (FNC) was synthesized based on the secondary calcination method, and the feasibility of this material for enhanced AD treatment of azo dye wastewater and its mechanism were investigated. FNC not only formed richer conducting functional groups, but also generated Fe2+/Fe3+ redox pairs. The decolorization efficiency of Congo red and AD properties (e.g., methane production) were enhanced by FNC. After adding FNC, the content of extracellular polymeric substances (EPS) and the ratio of proteins remained stable under the impact of Congo red, which greatly protected the internal microbial community. This was mainly contributed to the excellent electrochemical properties of FNC, which strengthened the microbial extracellular electron transfer and realized the coupled mechanism of action: On the one hand, an electron transfer bridge between decolorizing bacteria and dyes was constructed to achieve rapid decolorization of azo dyes and mitigate the impact on methanogenic bacteria; On the other hand, the stability of AnGS was enhanced based on enhanced extracellular polymeric substances secretion, microbial community and direct interspecies electron transfer (DIET) process. This study provides a new idea for enhanced AD treatment of azo dyes wastewater.

Fungi from Antarctic marine sediment: characterization and assessment for textile dye decolorization and detoxification.

Cold-adapted microorganisms can produce enzymes with activity at low and mild temperatures, which can be applied to environmental biotechnology. This study aimed to characterize 20 Antarctic fungi to identify their genus (ITS rDNA marker) and growth temperatures and evaluate their ability to decolorize and detoxify the textile dye indigo carmine (IC). An individual screening was performed to assess the decolorization and detoxification of IC by the isolates, as well as in consortia with other fungi. The isolates were affiliated with seven ascomycete genera: Aspergillus (n = 4), Cosmospora (n = 2), Leuconeurospora (n = 2), Penicillium (n = 3), Pseudogymnoascus (n = 6), Thelebolus (n = 2), and Trichoderma (n = 1). The two isolates from the genus Leuconeurospora were characterized as psychrophilic, while the others were psychrotolerant. The Penicillium isolates were able to decolorize between 60 and 82% of IC. The isolates identified as Pseudogymnoascus showed the best detoxification capacity, with results varying from 49 to 74%. The consortium using only Antarctic ascomycetes (C1) showed 45% of decolorization, while the consortia with the addition of basidiomycetes (C1 + Peniophora and C1 + Pholiota) showed 40% and 50%, respectively. The consortia C1 with the addition of the basidiomycetes presented a lower toxicity after the treatments. In addition, a higher fungal biomass was produced in the presence of dye when compared with the experiment without the dye, which can be indicative of dye metabolization. The results highlight the potential of marine-derived Antarctic fungi in the process of textile dye degradation. The findings encourage further studies to elucidate the degradation and detoxification pathways of the dye IC by these fungal isolates.

Simple precipitation synthesis and solar light-driven photocatalytic degradation of Ag3PO4 floating photocatalysts

Abstract A highly efficient and stable photocatalyst, Ag3PO4, was prepared using a simple co-precipitation method at room temperature. The precursors used in this process were AgNO3 and K2HPO4. The resulting Ag3PO4 photocatalyst forms irregularly-shaped spheres with diameters ranging from 300 to 1 μm. The shape of the Ag3PO4 photocatalyst slightly changes when different surfactants (PVA, PVP, PEG) are used. The powdered Ag3PO4 photocatalyst exhibits excellent visible light-driven photocatalytic performance. It is capable of decomposing rhodamine B (RhB) as a model pollutant in just 5 min under visible light irradiation. This performance is quite remarkable. Interestingly, Ag3PO4 floating composite sheets have been achieved using polystyrene (PS) and fumed silica Aerosil 200. After three cycles, the decolorization of RhB dyes remains at 87% with the 30% Ag3PO4@PS/Aerosil 200 sheet. This indicates that the Ag3PO4@PS/Aerosil 200 photocatalyst is highly reusable and stable.

Decolorization of Textile Dyes by Extracellular Enzymes Produced from Trametes sanguinea and Perenniporia taephropora Immobilized on Natural Media

The color of textile wastewater is still a main problem in wastewater treatment by biological processes. The colored effluents from textile factories usually exceed effluent standards. Therefore, various innovations were developed to treat textile wastewater for decolorization in the effluents. This research aims to decolorize textile wastewater by immobilizing white rot fungi degradation. At first, the 11 fungal stains were tested to find the decolorized efficiency then the high decolorized efficiency fungal stains were immobilized on four material media, namely water hyacinth stalks, coconut husk, corn cob, and loofah. After that, the immobilized fungi were cultivated in the culture media at 30, 60, and 120 C/N ratios, respectively. The results showed that Trametes sanguinea and Perenniporia tephropora were two stains with a high decolorized efficiency of 68.8% and 67.5% respectively, and the decolorized efficiency was increased when immobilized on loofahs and fed with 120 C/N ratio medium. In a comparison of two fungal stains, P. tephropora was found more suitable for the decolorization of textile wastewater than T. sanguinea because T. sanguinea could produce red-orange pigments that induced the colored enhancement in wastewater over time. Finally, immobilized P. tephropora was cultivated in a 120 C/N ratio medium within a 10 L continuous stirred tank reactor (8 L working volume) to investigate the decolorized efficiency, enzymatic activity, and repeated batch. It was found that three repeated cycles were carried out by reusing the immobilized P. tephropora and the highest decolorized efficiency was 63.4%. The enzymatic activity of laccase, manganese peroxidase, and lignin peroxidase was 15.5 U/L, 85.9 U/L, and 0 U/L, respectively

Toxicity and decomposition activity inhibition of VO2 micro/nanoparticles to white rot fungus Phanerochaete chrysosporium

Vanadium dioxide (VO2) is an excellent phase transition material widely used in various applications, and thus inevitably enters the environment via different routes and encounters various organisms. Nonetheless, limited information is available on the environmental hazards of VO2. In this study, we investigated the impact of two commercial VO2 particles, nanosized S-VO2 and micro-sized M-VO2 on the white rot fungus Phanerochaete chrysosporium. The growth of P. chrysosporium is significantly affected by VO2 particles, with S-VO2 displaying a higher inhibitory effect on weight gain. In addition, VO2 at high concentrations inhibits the formation of fungal fibrous hyphae and disrupts the integrity of fungus cells as evidenced by the cell membrane damage and the loss of cytoplasm. Notably, at 200 μg/mL, S-VO2 completely alters the morphology of P. chrysosporium, while the M-VO2 treatment does not affect the mycelium formation of P. chrysosporium. Additionally, VO2 particles inhibit the laccase activity secreted by P. chrysosporium, and thus prevent the dye decoloration and sawdust decomposition by P. chrysosporium. The mechanism underlying this toxicity is related to the dissolution of VO2 and the oxidative stress induced by VO2. Overall, our findings suggest that VO2 nanoparticles pose significant environmental hazards and risks to white rot fungi.