•Mediated detoxification of spent sulphite liquor via laccase from Trametes versicolor was investigated.•Analysis and optimisation using an in-situ NMR-spectroscopy method.•Futhermore was applied a ...valid statistical model for the impact on the aromatic degradation.
Within this study the mediated detoxification of spent sulphite liquor via laccase from Trametes versicolor was analysed and optimised using an in-situ NMR-spectroscopy method. The enzymatic degradation kinetic was optimised using the degradation rate of aromatic compounds as indirect parameter. Via response surface methodology the impact of the temperature, the pH and the enzyme concentration was analysed and the conditions were optimised focusing on optimal detoxification. The results of the statistical calculation revealed a valid statistical model for the optimal impact on the aromatic degradation with a temperature of 31 °C, a pH of 6 and a laccase concentrations of 179 U g−1 dry matter of spent sulphite liquor. By using these conditions 88.73% of aromatic compounds could be degraded.
•Isoproturon can be completely degraded by laccase-mediator systems.•Synthetic mediators are more effective for the isoproturon degradation.•Mediators can affect laccase stability in the degradation ...of isoproturon.•PEG can reduce the HBT dosage and enhance the degradation rate of isoproturon.•A higher degradation rate of isoproturon was observed in real wastewater.
This study investigated the degradation of the herbicide isoproturon using Trametes versicolor laccase and its laccase-mediator systems. Isoproturon was poorly degraded with laccase alone, due to the presence of the relatively strong withdrawing electron group (NHCON(CH3)2) in the chemical structure of isoproturon. This study showed that laccase-mediator systems can effectively enhance the degradation rate of isoproturon. Within 24h, isoproturon was completely degraded in the presence of 0.3U/mL laccase and 1mM 1-hydroxybenzotriazole (HBT). Compared with natural mediators, synthetic mediators are more effective in the laccase-mediated degradation of isoproturon. However, laccase activity rapidly declined in the presence of the synthetic mediator HBT. Degradation occurred at an acidic pH and optimum temperature was 50°C. A high concentration (10mM) of metal ions Cu2+, Zn2+ and Cd2+ positively enhanced isoproturon degradation with the laccase-HBT system. Polyethylene glycol (PEG) can reduce the HBT dosage in isoproturon degradation with the laccase-HBT system and enhance the degradation rate of isoproturon by increasing laccase stability. Moreover, a higher degradation rate of isoproturon was observed when incubating isoproturon with the laccase-HBT system in real wastewater compared to that in sodium citrate buffer. Finally, transformation products showed much lower ecotoxicity to green algae than the original isoproturon. This study concludes that laccase-mediator systems have great potential to treat industrial wastewater containing the herbicide isoproturon.
Hospital effluents contribute to the occurrence of emerging contaminants in the environment due to their high load of pharmaceutical active compounds (PhACs) and some endocrine disruptor compounds ...(EDCs). Nowadays, hospital wastewaters are co-treated with urban wastewater; however, the dilution factor and the inefficiency of wastewater treatment plants in the removal of PhACs and EDCs make inappropriate the co-treatment of both effluents. In this paper, a new alternative to pre-treat hospital wastewater concerning the removal of PhACs and EDCs is presented. The treatment was carried out in a batch fluidized bed bioreactor under sterile and non-sterile conditions with Trametes versicolor pellets. Results on non-sterile experiments pointed out that 46 out of the 51 detected PhACs and EDCs were partially to completely removed. The total initial PhAC amount into the bioreactor was 8185μg in sterile treatment and 8426μg in non-sterile treatment, and the overall load elimination was 83.2% and 53.3% in their respective treatments. In addition, the Microtox test showed reduction of wastewater toxicity after the treatment. Hence, the good efficiency of the fungal treatment regarding removal of the wide diversity of PhACs and EDCs detected in hospital effluents is demonstrated.
•Hospital wastewaters are treated in a fungal bioreactor with Trametes versicolor.•We study the removal of emerging contaminants under sterile and non-sterile conditions.•46 out of 51 detected pharmaceuticals are degraded in non-sterile conditions.•Diclofenac and the human metabolites of carbamazepine are efficiently removed.
► Coffee ground, olive mill wastewater sludge and poultry manure were co-composted. ► Effect of Trametes versicolor on the humification process was investigated. ► Compost was mature with germination ...index of 120% after 20wk composting. ► Inoculation improved 1.75 times humic acid production at the end of the process. ► Polyphenols and lignin were also reduced by 72% and 51% respectively.
The co-composting of spent coffee grounds, olive mill wastewater sludge and poultry manure was investigated on a semi-industrial scale. In order to reduce the toxicity of the phenolic fraction and to improve the degree of composting humification, composts were inoculated with the white-rot fungus Trametes versicolor in the early stages of the maturation phase.
During composting, a range of physico-chemical parameters (temperature and both organic matter and C/N reduction), total organic carbon, total nitrogen, elemental composition, lignin degradation and spectroscopic characteristics of the humic acids (HAs) were determined; impacts of the composting process on germination index of Hordeum vulgare and Lactuca sativa were assessed. The coffee waste proved to be a highly compostable feedstock, resulting in mature final compost with a germination index of 120% in less than 5months composting. In addition, inoculation with T. versicolor led to a greater degree of aromatization of HA than in the control pile. Moreover, in the inoculated mixture, lignin degradation was three times greater and HA increased by 30% (P<0.05), compared to the control pile. In the T. versicolor inoculated mixture, the averages of C and N were significantly enhanced in the HA molecules (P<0.05), by 26% and 22%, respectively. This improvement in the degree of humification was confirmed by the ratio of optical densities of HA solutions at 465 and 665nm which was lower for HA from the treated mixture (4.5) than that from the control pile (5.4).
The extensive use of sulfonamides (SNs) in animal husbandry has led to an unintentional widespread occurrence in several environmental compartments. The implementation of regulations and management ...recommendations to reduce the potential risk of development of antibiotic resistances necessitates detailed knowledge on their fate in soil. We present results from two independent incubation studies of 15N-labeled sulfadiazines (SDZ) which focused on identifying binding types in bound residues. In the first study 15N-amino labeled SDZ was incubated with two previously isolated humic acids in the presence and absence of Trametes versicolor laccase, while in the second study 15N-double-labeled SDZ was incubated with a typical agricultural Luvisol and the humic acid fraction isolated after sequential extraction of the soil. The freeze-dried humic acid fractions of both studies were then analyzed by 15N-CPMAS NMR and compared with the 15N-spectra of synthesized model compounds. In both studies amide bonds and Michael adducts were identified, while formation of imine bonds could be excluded. In the humic acid study, where less harsh extraction methods were applied, possible formation of H-bridging and sequestration were additionally detected.
Laccase-mediator systems (LMS) have been widely studied for their capacity to oxidize the nonphenolic subunits of lignin (70–90% of the polymer). The phenolic subunits (10–30% of the polymer), which ...can also be oxidized without mediators, have received considerably less attention. Consequently, it remains unclear to what extent the presence of a mediator influences the reactions of the phenolic subunits of lignin. To get more insight in this, UHPLC-MS was used to study the reactions of a phenolic lignin dimer (GBG), initiated by a laccase from Trametes versicolor, alone or in combination with the mediators HBT and ABTS. The role of HBT was negligible, as its oxidation by laccase occurred slowly in comparison to that of GBG. Laccase and laccase/HBT oxidized GBG at a comparable rate, resulting in extensive polymerization of GBG. In contrast, laccase/ABTS converted GBG at a higher rate, as GBG was oxidized both directly by laccase but also by ABTS radical cations, which were rapidly formed by laccase. The laccase/ABTS system resulted in Cα oxidation of GBG and coupling of ABTS to GBG, rather than polymerization of GBG. Based on these results, we propose reaction pathways of phenolic lignin model compounds with laccase/HBT and laccase/ABTS.
The objective of this work was to evaluate the post-treatment of an anaerobic recalcitrant effluent (anaerobically-treated weak black liquor, AnE) in an aerobic, upflow reactor packed with "biocubes" ...of Trametes versicolor immobilized onto small cubes of holm oak wood. The treated effluent (named anaerobic effluent; AnE) from an anaerobic fluidized bed reactor was fed to an up-flow aerobic fungal packed bed reactor (PBR). Two HRT were tested in this unit, namely 5 and 2.5 days; the PBR operated 60 days at 5-day HRT and 35 days at 2.5-day HRT. The aerobic packed bench scale reactor was a glass column 1.5 L total geometric volume containing 0.75 L biocubes of T. versicolor immobilized onto holm oak wood small cubes of 5 mm side. The reactor was operated at 25 C. The pH of the AnE was adjusted to 4.5 before feeding; no carbohydrates or other soluble carbon source was supplemented. The fungal packed bed bioreactor averaged organic matter removals of 30% and 32% COD basis, during an experimental run of 60 days at 5-day HRT and 35 days at 2.5-day HRT, respectively. Colour and ligninoids contents were removed at higher percentages (69% and 54% respectively, average of both HRT). There was no significant difference between reactor performance at 5- and 2.5-day HRT, so, operation at 2.5-day HRT is recommended since reactor throughput is double. Activity of manganese peroxidase and laccase was found during the entire operation of the fungal PBR whereas lignin peroxidase activity practically disappeared in the second operation period. In general, enzyme activities were higher in the first period of operation (5-day HRT) than at 2.5-day HRT. To the best of our knowledge, this is one of the few works that demonstrated extended performance (3 months) of a fungal bioreactor for the treatment of a recalcitrant wastewater with no supplementation of glucose or other expensive, soluble carbohydrate.
Laccase production by fungal growth on agrifood waste is still poorly studied. Trametes versicolor K1 isolated from palm bark produced a yellow non glycosylated laccase from tomato waste based medium ...(TMT) and a blue glycosylated laccase on glucose medium (GLU). Lignocellulosic biomass, such as pinecones (PIN), palm leaves (PLM), olive pomace (OLV), and alfa stems (ALF) have also been used as growth medium for T. versicolor K1. In these conditions, very low or no laccase production was observed. When peptone was supplied in TMT medium, the laccase activity increased from 4170 U/L to 8618 U/L. By increasing the culture volume up to 1 L, laccase production on TMT was 9929 U/L. The yellow laccase (TmtLac) was purified from the supernatant TMT medium and has shown similar characteristics with the blue laccase (GluLac) purified from the GLU medium. Their apparent protein size was 63 kDa. Catalytic activities of the yellow form were not very different from those of the blue form, but specific activity of the purified yellow laccase produced on tomato waste was much higher. The Km and Vm values for four substrates, ABTS, DMP, guaiacol, and pyrogallol were almost similar for both isoenzymes. The optimum pH and temperature were respectively 4.0 and 50 °C. Although the level of glycosylation is clearly different, the thermostability of TmtLac and GluLac are quite similar. TmtLac is even slightly more tolerant at 60 °C for 24 h than GluLac. Moreover TmtLac showed greater stability at alkaline pH after 24 h compared to that of GluLac.We demonstrate that activity of the yellow TmtLac is not significantly affected compared to the blue laccase and that tomato waste is a simple and interesting lignocellulosic substrate to the laccase producer Trametes sp.
•Trametes versicolor K1 from Algeria's semi-arid zone produces blue and yellow laccase.•Laccase was blue in a glucose-based medium, while yellow in a tomato waste medium.•The produced laccase displays a high pH stability in acidic and alkaline environments.•Yellow laccase was poorly glycosylated, whereas blue laccase was highly glycosylated.•Laccase produced on tomato waste successfully maintain its catalytic efficiency.
This study aimed at the development of a competitive and sustainable mycelium-based insulation material with low thermal conductivity. The investigated substrates were a) beech sawdust (SD), b) beech ...SD supplemented with further nutrients, c) spent mushroom substrate (SMS) as well as d) SMS supplemented with further nutrients. Substrates have been inoculated with Ganoderma lucidum or Trametes versicolor. Irrespective the substrate supplied, T. versicolor showed an overall good growth performance with a mycelial growth rate of 7.4–11.8 mm day−1. The mycelial density was in the range of 190–200 kg m−3 and the handling properties of were overall good. G. lucidum did grow on SD-based substrates at a mycelial growth rate between 5.9 and 6.9 mm day−1. Conversely, SMS inhibited the growth of G. lucidum. Results revealed that T. versicolor can effectively recycle SMS and G. lucidum SD-based substrates into lightweight materials with a low thermal conductivity (0.06–0.07 W m−1∙K−1).
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•Ganoderma lucidum did not grow on spent mushroom substrate but on sawdust.•Trametes versicolor did grow on both substrates.•Both substrates and fungi result in materials with a low thermal conductivity.•Mycelium-based composites were easy to handle and useable for thermal insulation.
This work evaluates the potential of polyacrylonitrile particles (PAN) as support for laccase from Trametes versicolor immobilization. The slurry polymerization method forms mesoporous particles with ...low surface area and low maximum pore volume in desorption. The particles were chemically modified by consecutive alkaline and acid hydrolysis, followed by amination and activation with glutaraldehyde to enzyme immobilization. The laccase immobilization yield was 99.48% and 14.29% using the functionalized and non‐functionalized particles, respectively. The enzyme activity was measured by the oxidation of 2,2′‐azino‐bis(3‐ethylbenzthiazoline‐6‐sulfonic acid) at different pHs and temperatures. The PAN/laccase derivative was hyperactivated at pH 3, up to 3 times higher than the free enzyme, and performed better at 50°C after 6 h of incubation, with relative activity up to 33% higher than the free enzyme. However, both enzymes denatured when the conditions reached pH 8 and 70°C. The PAN/laccase retained 89% of the initial activity after 30 days of storage at 5°C. It was possible to reuse the enzymatic derivative for 5 cycles, with up to 50% residual activity, under 50°C and pH 3. These results show the potential of this new support for laccase immobilization and further applications of industrial interest.
Functionalization of polyacrylonitrile particles for laccase immobilization.
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