•Fungi can be promising candidates for the removal of organic load and nutrients from municipal wastewater.•T. versicolor and A. luchuensis use biosorption and metabolism activity for phosphorus ...removal.•Adjustment of pH to 5.5 has an effect on ammonia nitrogen and total organic carbon removal.•Bioaugmentation by fungi has been proposed as a promising strategy for municipal wastewater treatment.
Discharge of organic load from treated wastewater may cause environmental eutrophication. Recently, fungi have gained much attention due to their removal of pharmaceutical substances by enzymatic degradation and adsorption. However, the fungal effect in removing nutrients is less investigated. Therefore, two fungal species, the white-rot fungus T. versicolor as a laboratory strain and the mold A. luchuensis as an environmental isolate from the municipal wastewater treatment plant, were studied to determine the fungal potential for phosphorus, nitrogen, and the total organic carbon removal from municipal wastewater, carrying out a batch scale experiment to a fluidized bed pelleted bioreactor. During the batch scale experiment, the total removal (99.9 %) of phosphorus by T. versicolor was attained after a 6 h-long incubation period while the maximal removal efficiency (99.9 %) for phosphorus from A. luchuensis was gained after an incubation period of 24 h. Furthermore, both fungi showed that the pH adjustment to 5.5 kept the concentration of nitrogen constant and stabilized the total organic carbon reduction process for the entire incubation period. The results from the fluidized bed bioreactor demonstrated opposite tendencies on a nutrient removal comparing to a batch experiment where no significant effect on phosphorus, nitrogen, and total organics carbon reduction was observed. The obtained results from this study of batch and fluidized bed bioreactor experiments are a promising starting point for a successful fungal treatment optimization and application to wastewater treatment.
•A process for apple juice clarification is proposed using an immobilized laccase.•A low-cost support “coconut fiber” was used with success in the laccase immobilization.•The derivative showed better ...stability in relation to the free enzyme with possibility of reuse.•This immobilized enzyme can be used to remove phenol compounds from apple juice.•The enzyme can be removed from the final product because it is bound in a solid matrix.
Waste materials from agroindustry constituted from lignocellulose have been used in the immobilization process of technological interest enzymes to reduce costs, increasing the value of such products. In the present study, green coconut husk was used to obtain fibers (CF) that were treated through thermal decompression in combination with either acid or alkaline medium. A solid support for enzyme immobilization was prepared using the pretreated CF activated with glyoxyl or glutaraldehyde and was used to immobilize the laccase enzyme (EC 1.10.3.2) produced by Trametes versicolor. Immobilized enzyme retained up to 59±1% of the initial activity and showed maximum immobilization profile of 98±1%. The thermal stability was higher when laccase was immobilized on alkaline pretreated support with increments of 6.8-fold (laccase-glutaraldehyde-FC) up to 16.5-fold (laccase-glyoxyl-FC) of the soluble enzyme. The laccase-glutaraldehyde-CF achieved excellent results in the clarification of apple juice, reducing 61±1% of the original juice color and 29±1% of its turbidity, retaining up to 100% of the initial activity after a 10-times reuse assay. This study is pioneer in the utilization of low-cost support for laccase immobilization with application in the juice fruits clarification.
Laccases have wide range of substrate specificity and find applications from pulp industry to waste water remediation. Laccases have also been used in combined pretreatment of biomass hydrolyzates to ...remove enzymatic and fermentation inhibitors. In this study, laccase production by Trametes versicolor strains isolated from different regions of the United States was induced using copper salts. T. versicolor crude culture filtrates (CCF), without any purification step, were tested for removal of model inhibitor compounds as well as in poplar and rice straw pretreatment hydrolyzates. Phenolic inhibitors were removed by 76% and 94% from the dilute acid hydrolyzates of rice straw and poplar, respectively, when incubated with the CCF for 12h, at room temperature. Xylo-oligosaccharide concentrations present in rice straw hydrolyzates were reduced by 64% when incubated with T. versicolor CCF. T. versicolor CCF could be a low cost technology for decreasing enzymatic and fermentation inhibitors.
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•Pallet wood was the best substrate for the immobilization of Trametes versicolor.•Trickling packed and fluidized bed reactors were proved for HWW treatment.•The use of complex ...pellets for HWW in fluidized bed reactor resulted not scalable.•High removals of PhACs were obtained with a trickling packed reactor for 49days.
Hospital wastewater is a major source of pharmaceutically active compounds (PhACs), which are not all removed in conventional wastewater treatment plants. White rot fungi can degrade PhACs, but their application has been limited to non-sterile conditions due to the competition with other microorganisms for growth. In this study, immobilization of Trametes versicolor on different lignocellulosic supports was studied as strategy to ensure fungal survival under continuous treatment conditions. A fluidized bed reactor and a trickling packed-bed reactor with T. versicolor immobilized on pallet wood were employed for the removal of ibuprofen, ketoprofen and naproxen. Best results were obtained with the trickling packed-bed reactor, which operated for 49days with high removal values in real hospital wastewater.
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•Trametes versicolor is capable of simultaneous biodegrading CAP and removing Cd.•Nine transformation products (TPs) were identified, including six novel TPs.•Two novel CAP ...biodegradation pathways were proposed through the TPs.•Biodegradation and adsorption were the main mechanism of CAP removal by T. versicolor.•Cellular accumulation and surface adsorption were the main mechanism of Cd removal.
The recalcitrant chloramphenicol (CAP) combined with heavy metals cadmium (Cd) commonly co-existed in the environment, posing threat to environment health. The capacity of Trametes versicolor to remove/biodegrade CAP in air-pulse fluidized-bed reactor was evaluated, even under Cd stress. T. versicolor could remove 44 % CAP of 5 mg/L in 15 days, even 51 % CAP under 1 mg/L Cd stress. Sustained Cd stress inhibited CAP biodegradation and Cd removal in a 5-batches of a 5-days cycle sequential batch reactor. Nine transformation products and two novel pathways were proposed, with initial multi-step transformation reaction into CP2 and allylic alcohol, respectively. Furthermore, the main mechanism of Cd removal by T. versicolor was extracellular surface bioadsorption and intracellular accumulation. This study filled the gap of the mechanism of simultaneous CAP removal/biodegradation and Cd removal by white-rot fungi T. versicolor, which offer a theoretical basis for future application of biological removal of CAP containing wastewater.
The elimination of 81 pharmaceuticals (PhACs) by means of a biological treatment based on the fungus Trametes versicolor was evaluated in this work. PhAC removal studied in different types of ...wastewaters (urban, reverse osmosis concentrate, hospital, and veterinary hospital wastewaters) were reviewed and compared with conventional activated sludge (CAS) treatment. In addition, hazard indexes were calculated based on the exposure levels and ecotoxicity for each compound and used for the evaluation of the contaminants removal. PhAC elimination achieved with the fungal treatment (mean value 76%) was similar or slightly worse than the elimination achieved in the CAS treatment (85%). However, the fungal reactor was superior in removing more hazardous compounds (antibiotics and psychiatric drugs) than the conventional activated sludge in terms of environmental risk reduction (93% and 53% of reduction respectively). Fungal treatment can thus be considered as a good alternative to conventional treatment technologies for the elimination of PhACs from wastewaters.
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•Efficiency of fungal treatment was evaluated in different wastewater effluents.•Removal of up to 81 pharmaceuticals in all treatments was estimated.•Reduction of environmental risk after fungal treatment was also assessed.•Antibiotics and psychiatric drugs were better removed by fungal treatment.•Fungal treatment showed promising results from an ecotoxicological point of view.
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•TX100 or RL had significant influence on the interactions of Lac with phenol.•Both surfactants changed the binding site of Lac bound to phenol.•Single TX100 or RL decreased the ...binding energy between phenol and Lac.•The behavior of water molecules was also transformed due to the formation of HBs.
Some surfactants can enhance the removal of phenol by laccase (Lac) in various industrial effluents. Their behavior and function in the biodegradation of phenolic wastewater have been experimentally reported by many researchers, but the underlying molecular mechanism is still unclear. Therefore, the interaction mechanisms of phenol with Lac from Trametes versicolor were investigated in the presence or absence of Triton X-100 (TX100) or rhamnolipid (RL) by molecular docking and molecular dynamics (MD) simulations. The results indicate that phenol contacts with an active site of Lac by hydrogen bonds (HBs) and van der Waals (vdW) interactions in aqueous solution for maintaining its stability. The presence of TX100 or RL results in the significant changes of enzymatic conformations. Meanwhile, the hydrophobic parts of surfactants contact with the outside surface of Lac. These changes lead to the decrease of binding energy between phenol and Lac. The migration behavior of water molecules within hydration shell is also inevitably affected. Therefore, the amphipathic TX100 or RL may influence the phenol degradation ability of Lac by modulating their interactions and water environment. This study offers molecular level of understanding on the function of surfactants in biosystem.
In ruminant nutrition, there is an increasing interest for ingredients that do not compete with human nutrition. Ruminants are specialists in digesting carbohydrates in plant cell walls; therefore ...lignocellulosic biomass has potential in ruminant nutrition. The presence of lignin in biomass, however, limits the effective utilization of cellulose and hemicellulose. Currently, most often chemical and/or physical treatments are used to degrade lignin. White rot fungi are selective lignin degraders and can be a potential alternative to current methods which involve potentially toxic chemicals and expensive equipment. This review provides an overview of research conducted to date on fungal pretreatment of lignocellulosic biomass for ruminant feeds. White rot fungi colonize lignocellulosic biomass, and during colonization produce enzymes, radicals and other small compounds to breakdown lignin. The mechanisms on how these fungi degrade lignin are not fully understood, but fungal strain, the origin of lignocellulose and culture conditions have a major effect on the process. Ceriporiopsis subvermispora and Pleurotus eryngii are the most effective fungi to improve the nutritional value of biomass for ruminant nutrition. However, conclusions on the effectiveness of fungal delignification are difficult to draw due to a lack of standardized culture conditions and information on fungal strains used. Methods of analysis between studies are not uniform for both chemical analysis and in vitro degradation measurements. In vivo studies are limited in number and mostly describing digestibility after mushroom production, when the fungus has degraded cellulose to derive energy for fruit body development.
Optimization of fungal pretreatment is required to shorten the process of delignification and make it more selective for lignin. In this respect, future research should focus on optimization of culture conditions and gene expression to obtain a better understanding of the mechanisms involved and allow the development of superior fungal strains to degrade lignin in biomass.
The biomixture is the major constituent of a biopurification system and one of the most important factors in its efficiency; hence the selection of the components is crucial to ensure the efficient ...pesticides removal. Besides, bioaugmentation is an interesting approach for the optimization of these systems.
A mixed culture of the fungus Trametes versicolor SGNG1 and the actinobacteria Streptomyces sp. A2, A5, A11, and M7, was designed to inoculate the biomixtures, based on previously demonstrated ligninolytic and pesticide-degrading activities and the absence of antagonism among the strains. The presence of lindane and/or the inoculum in the biomixtures had no significant effect on the development of culturable microorganisms regardless the soil type. The consortium improved lindane dissipation achieving 81–87% of removal at 66 d of incubation in the different biomixtures, decreasing lindane half-life to an average of 24 d, i.e. 6-fold less than t1/2 of lindane in soils. However, after recontamination, only the bioaugmented biomixture of silty loam soil enhanced lindane dissipation and decreased the t1/2 compared to non-bioaugmented. The biomixture formulated with silty loam soil, sugarcane bagasse, and peat, inoculated with a fungal-actinobacterial consortium, could be appropriate for the treatment of agroindustrial effluents contaminated with organochlorine pesticides in biopurification systems.
•Lindane did not affect the growth of culturable microorganisms in the biomixtures.•Bioaugmentation improved lindane dissipation in the biomixtures of the three soils.•The consortium decreased lindane t1/2 to 6-fold less than t1/2 reported for soils.•After recontamination only the inoculated silty loam-biomixture reduced the t1/2.•This is the first report on fungal-actinobacterial bioaugmentation of biomixtures.
The contribution of the sorption processes in the elimination of pharmaceuticals (PhACs) during the fungal treatment of wastewater has been evaluated in this work. The sorption of four PhACs ...(carbamazepine, diclofenac, iopromide and venlafaxine) by 6 different fungi was first evaluated in batch experiments. Concentrations of PhACs in both liquid and solid (biomass) matrices from the fungal treatment were measured. Contribution of the sorption to the total removal of pollutants ranged between 3% and 13% in relation to the initial amount. The sorption of 47 PhACs in fungi was also evaluated in a fungal treatment performed in 26days in a continuous bioreactor treating wastewater from a veterinary hospital. PhACs levels measured in the fungal biomass were similar to those detected in conventional wastewater treatment (WWTP) sludge. This may suggest the necessity of manage fungal biomass as waste in the same manner that the WWTP sludge is managed.
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•Analytical methodology for PhACS in fungal biomass was developed.•Pharmaceuticals sorbed in the biomass in degradation experiments was measured.•Between 3 and 13% of PhACs elimination can be attributed to sorption processes.•Accumulation of PhACs in fungi is similar to that in sludge of conventional treatments.
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