Decolorization of the metal textile dye Lanaset Grey G by immobilized white-rot fungi

Improved productivity and dye removal performance of Trametes versicolor pellets using rice husk as a co-substrate

Pellet production represents a critical step for several processes requiring fungal biomass, nevertheless, its optimization is seldom reported. The use of finely ground rice husk as a microcarrier and co-substrate permitted a marked increase (≈ 2.7×) in the productivity of fungal pellet production using Trametes versicolor compared to traditional production methods. The pellets show similar structure and smaller size compared to typical sole-mycelium pellets, as well as comparable laccase activity. The efficiency of the pellets for biodegradation was confirmed by the removal of the crystal violet dye, achieving significantly faster decolorization rates compared to the traditionally produced pellets. The use of these pellets during the continuous treatment of the dye in a stirred tank bioreactor resulted in 97% decolorization operating at a hydraulic residence time of 4.5 d.

Adsorption and decolorization study of reactive black 5 by immobilized metal-organic framework of UiO-66 and Gloeophyllum trabeum fungus

This study aimed to investigate immobilized metal-organic framework (MOF) UiO-66 and brown-rot fungus Gloeophyllum trabeum (GT) in PVA-SA matrices for adsorption and decolorization of reactive black 5 (RB5). Furthermore, UiO-66/GT@PVA-SA composite was successfully fabricated and obtained by immobilizing UiO-66 and GT mycelia into a mixture of PVA-SA. This composite demonstrated a decolorization ability of 80.12% for RB5 after 7 days. The composite's reusability was assessed for three cycles; at last, it only achieved 21%. This study reported that adsorption of RB5 by the composite followed a pseudo-second-order kinetic model with a correlation coefficient (R2) of 0.9997. The Freundlich model was found to be suitable for the isotherm adsorption. The process was also spontaneous and feasible, as indicated by the negative ΔG value. Subsequently, four metabolite products resulting from decolorization of RB5 by UiO-66/GT@PVA-SA composite were proposed, namely: C24H19N5Na2O13S4 (m/z = 762), C10H13N2O8S2- (m/z = 353), C12H9N4O7S2- (m/z = 384), and C10H13O8S2- (m/z = 325).

Optimization of the Decolorization of the Reactive Black 5 by a Laccase-like Active Cell-Free Supernatant from Coriolopsis gallica

The textile industry generates huge volumes of colored wastewater that require multiple treatments to remove persistent toxic and carcinogenic dyes. Here we studied the decolorization of a recalcitrant azo dye, Reactive Black 5, using laccase-like active cell-free supernatant from Coriolopsis gallica. Decolorization was optimized in a 1 mL reaction mixture using the response surface methodology (RSM) to test the influence of five variables, i.e., laccase-like activity, dye concentration, redox mediator (HBT) concentration, pH, and temperature, on dye decolorization. Statistical tests were used to determine regression coefficients and the quality of the models used, as well as significant factors and/or factor interactions. Maximum decolorization was achieved at 120 min (82 ± 0.6%) with the optimized protocol, i.e., laccase-like activity at 0.5 U mL−1, dye at 25 mg L−1, HBT at 4.5 mM, pH at 4.2 and temperature at 55 °C. The model proved significant (ANOVA test with p < 0.001): coefficient of determination (R²) was 89.78%, adjusted coefficient of determination (R²A) was 87.85%, and root mean square error (RMSE) was 10.48%. The reaction conditions yielding maximum decolorization were tested in a larger volume of 500 mL reaction mixture. Under these conditions, the decolorization rate reached 77.6 ± 0.4%, which was in good agreement with the value found on the 1 mL scale. RB5 decolorization was further evaluated using the UV-visible spectra of the treated and untreated dyes.

Study on treatment of acid red G with bio-carbon compound immobilized white rot fungi

Corn straw biochar was used as a carrier to immobilize white rot fungi and the removal performance of immobilized pellets for acid red G (ARG) dye was studied. The results showed that the removal rate of ARG could reach 96.17% under the best preparation conditions of immobilized pellets (3% sodium alginate concentration, 0.7% corn straw biochar, 5% white rot fungus mycelium suspension, 4% CaCl₂, and 36 h immobilization time). The orthogonal test results showed that the best combination was the immobilized pellets dosage of 200/100 mL, pH of 4.5, rotation speed of 150 r/min, and initial concentration of 20 mg/L dye at 30 °C. The degradation pathway of ARG by immobilized microspheres was studied by ultraviolet-visible spectrometer, Fourier transform infrared spectroscopy, and liquid chromatography-mass spectrometry. The results showed that ARG was degraded into aniline and 5-(acetamino)-4-hydroxy-3-amino-2,7-naphthalene disulfonic acid. Aniline was further deaminated to form benzene, and benzene was ring opened to form other organic compounds; 5-(acetylamino)-4-hydroxy-3-amino-2,7-naphthalene disulfonic acid was dehydroxylated to form 5-(acetylamino)-3-amino-2,7-naphthalene disulfonic acid. This study shows that the prepared biochar immobilized pellets can be used as an efficient water treatment material to remove ARG dye from wastewater.

Biodegradation of C20 carbon clusters from Diesel Fuel by Coriolopsis gallica: optimization, metabolic pathway, phytotoxicity

This study is to test the capacity of the white rot fungus Coriolopsis gallica for the biodegradation of Diesel Fuel hydrocarbons (DHs). Using the experimental face centered central composite design (FCCCD), culture conditions of the Diesel-mended medium were optimized to reach 110.43% of DHs removal rate, and l5267.35 U L-1 of laccase production by C. gallica, simultaneously. The optimal combination of the cultural parameters was: Diesel concentration range of 2.95-3.14%, inoculum size of 3%, incubation time of 15 days, Tween 80 concentration of 0.05%, and the ratio glucose/peptone (G/P) range of 10.15-10.27. Further, the degradation ability of C. gallica for Diesel Fuel was evaluated through mycelial pellets uptake and oxidative action of fungal enzymes in the optimized degrading-medium using gas chromatography-mass spectrometry (GC-MS). Cyclosiloxanes and C20 PAHs detected as the major compound in Diesel Fuel (46%) was completely bio-transformed to simple metabolites including, essentially benzoic acid ester (71%), alcohols (1.52%) epoxy alkane (1.07%), carboxylic acids (1.24%) and quinones (0.33%). Germination rate and root elongation, as a rapid phytotoxicity test demonstrated that toxicity of Diesel's PAHs is minimized by fungal treatment.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s13205-021-02769-w.

Immobilization of yeast cell walls with surface displayed laccase from Streptomyces cyaneus within dopamine-alginate beads for dye decolorization

High amounts of toxic textile dyes are released into the environment due to coloring and wastewaters treatment processes' inefficiency. To remove dyes from the environment and wastewaters, researchers focused on applying immobilized enzymes due to mild reaction conditions and enzyme nontoxicity. Laccases are oxidases with wide substrate specificity, capable of degradation of many different dye types. Laccase from Streptomyces cyaneus was expressed on the surface of Saccharomyces cerevisiae EBY100 cells. The specific activity of surface-displayed laccase was increased by toluene-induced lysis to 3.1 U/g of cell walls. For cell wall laccase immobilization within hydrogel beads, alginate was modified by dopamine using periodate oxidation and reductive amination and characterized by UV-Vis, FTIR, and NMR spectroscopy. Cell wall laccase was immobilized within alginate and dopamine-alginate beads additionally cross-linked by oxygen and laccase. The immobilized enzyme's specific activity was two times higher using dopamine-alginate compared to native alginate beads, and immobilization yield increased 16 times. Cell wall laccase immobilized within dopamine-alginate beads decolorized Amido Black 10B, Reactive Black 5, Evans Blue, and Remazol Brilliant Blue with 100% efficiency and after ten rounds of multiple-use retained decolorization efficiency of 90% with Evans Blue and 61% with Amido Black.

Fungal mycelia functionalization with halloysite nanotubes for hyphal spreading and sorption behavior regulation: A new bio-ceramic hybrid for enhanced water treatment

Filamentous fungi are believed to remove a wide range of environmental xenobiotics due to their characteristically non-specific catabolic metabolisms. Nonetheless, irregular hyphal spreading can lead to clogging problems in treatment facilities and the dependence of pollutant bioavailability on hyphal surface features severely limits their applicability in water treatment. Here, we propose a scalable and facile methodology to structurally modify fungal hyphae, allowing for both the maximization of pollutant sorption and fungal pellet morphology self-regulation. Halloysite-doped mycelium architectures were efficiently constructed by dipping Aspergillus fumigatus pellets in halloysite nanotube-dispersed water. Ultrastructure analyses using scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy revealed that the nanotubes were mainly attached to the outer surface of the pellets. Fungal viability and exoenzyme production were hardly affected by the halloysites. Notably, nanotube doping appeared to be extremely robust given that detachments rarely occurred even in high concentrations of organic solvents and salt. It was also demonstrated that the doped halloysites weakened hyphal growth-driven gelation, thus maintaining sphere-like pellet structures. The water treatment potential of the hybrid fungal mycelia was assessed through both cationic toxic organic/inorganic-contaminated water and real dye industry wastewater clean-ups. Aided by the mesoporous halloysite sites on their surface, the removal abilities of the hybrid structures were significantly enhanced. Moreover, inherent low sorption ability of HNT for heavy metals was found to be overcome by the aid of fungal mycelia. Finally, universal feature of the dipping-based doping way was confirmed by using different filamentous fungi. Given that traditional approaches to effectively implement fungus-based water treatment are based mostly on polymer-based immobilization techniques, our proposed approach provides a novel and effective alternative via simple doping of living fungi with environmentally-benign clays such as halloysite nanotubes.

Degradation of Anthraquinone Dyes from Effluents: A Review Focusing on Enzymatic Dye Degradation with Industrial Potential

Up to 84 000 tons of dye can be lost in water, and 90 million tons of water are attributed annually to dye production and their application, mainly in the textile and leather industry, making the dyestuff industry responsible for up to 20% of the industrial water pollution. The majority of dyes industrially used today are aromatic compounds with complex, reinforced structures, with anthraquinone dyes being the second largest produced in terms of volume. Despite the progress on decolorization and degradation of azo dyes, very little attention has been given to anthraquinone dyes. Anthraquinone dyes pose a serious environmental problem as their reinforced structure makes them difficult to degrade naturally. Existing methods of decolorization might be effective but are neither efficient nor practical due to extended time, space, and cost requirements. Attention should be given to the emerging routes for dye decolorization via the enzymatic action of oxidoreductases, which have already a strong presence in various other bioremediation applications. This review will discusses the presence of anthraquinone dyes in the effluents and ways for their remediation from dyehouse effluents, focusing on enzymatic processes.

Decolourization and biodegradation of azo dye methyl red by Rhodococcus strain UCC 0016

In the present study, locally isolated Rhodococcus strains were attempted as biological tools for methyl red removal, a mutagenic azo dye posing threat to the environment if left untreated. Rhodococcus strain UCC 0016 demonstrated superior methyl red-decolourizing activity of 100% after 24 h at static condition in comparison to Rhodococcus strain UCC 0008 which recorded 65% decolourization after 72 h. Optimization of physicochemical parameters at 30°C, pH 7 and supplementing glucose as the carbon source resulted in improved methyl red-decolourizing activity at static condition and reduced the time taken to achieve complete decolourization by 80%. Higher concentration of methyl red (5 g/L) was able to be decolourized completely within 10 h by adopting the technology of immobilization. The encapsulated cells of Rhodococcus strain UCC 0016 demonstrated higher substrate affinity (K_m = 0.6995 g/L) and an accelerated rate of disappearance of methyl red (V_max = 0.3203 g/L/h) compared to the free cells. Furthermore, the gellan gum beads could be reused up to nine batches without substantial loss in the catalytic activity indicating the economic importance of this protocol. Analysis of methyl red degradation products revealed no germination inhibition on Triticum aestivum and Vigna radiata demonstrating complete toxicity removal of the parent dye after biological treatment. The occurrence of new and altered peaks (UV-Vis and FTIR) further supported the notion that the removal of methyl red by Rhodococcus strain UCC 0016 was indeed through biodegradation. Therefore, this strain has a huge potential as a candidate for efficient bioremediation of wastewater containing methyl red.

Phylogenetic and metabolic diversity of Tunisian forest wood-degrading fungi: a wealth of novelties and opportunities for biotechnology

In this study, 51 fungal strains were isolated from decaying wood samples collected from forests located in the Northwest of Tunisia in the vicinity of Bousalem, Ain Draham and Kef. Phylogenetic analysis based on the sequences of the internal transcribed spacers of the ribosomal DNA showed a high diversity among the 51 fungal isolates collection. Representatives of 25 genera and 29 species were identified, most of which were members of one of the following phyla (Ascomycota, Basidiomycota and Zygomycota). In addition to the phylogenetic diversity, a high diversity of secreted enzyme profiles was also detected among the fungal isolates. All fungal strains produced at least one of the following enzymes: laccase, cellulase, protease and/or lipase.

Enhanced removal of naproxen and carbamazepine from wastewater using a novel countercurrent seepage bioreactor immobilized with Phanerochaete chrysosporium under non-sterile conditions

A countercurrent seepage bioreactor immobilized with Phanerochaete chrysosporium was continuously operated under non-sterile conditions to treat a synthetic wastewater spiked with naproxen and carbamazepine (1000μg/L each) for 165days. There were no serious bacterial contaminations occurred during the operational period. Naproxen was always removed to the undetectable level regardless of the experimental conditions, while the average removal efficiency for carbamazepine, a well-known recalcitrant pharmaceutically active compound, reached around 80%. The excellent removal performance was mainly attributed to the application of countercurrent seepage mode and the cardhouse fabric of the carriers, which provided the high efficiency in the transfer of oxygen and nutrients inside the bioreactor. From the fungal immobilization combined with the temperature adjustment, the fungal activity including the enzyme production was protected as well as the bacterial contamination inside the reactor was suppressed effectively.

Synergistic removal of dyes by Myrothecium verrucaria immobilization on a chitosan–Fe membrane

A kind of novel, environmental friendly and efficient hybrid for the fungus and chitosan–Fe membrane has been fabricated by the alginate approach for efficient removal of aqueous dyes.

Aerobic decolorization and degradation of azo dyes by suspended growing cells and immobilized cells of a newly isolated yeast Magnusiomyces ingens LH-F1

Aerobic decolorization and degradation of azo dyes by both of suspended growing cells and immobilized cells of a newly isolated yeast strain LH-F1 were investigated in this study. A yeast strain LH-F1 capable of aerobically decolorizing various azo dyes (20mg/L) was identified as Magnusiomyces ingens basing on 26S rDNA analysis. Meanwhile, effects of different parameters on decolorization of Acid Red B by both of suspended growing cells and immobilized cells of strain LH-F1 were investigated. Furthermore, possible degradation pathway of the dye was proposed through analyzing metabolic intermediates using UV-Vis and HPLC-MS methods. As far as it is known, it is the first systematic research on a M. ingens strain which is capable of efficiently decolorizing azo dyes under aerobic condition. Additionally, this work would also provide a potentially useful microbial strain LH-F1 for treatment of industrial wastewaters containing azo dyes.