Montserrat Sarrà

Degradation of pharmaceuticals in non-sterile urban wastewater by Trametes versicolor in a fluidized bed bioreactor

The constant detection of pharmaceuticals (PhACs) in the environment demonstrates the inefficiency of conventional wastewater treatment plants to completely remove them from wastewaters. So far, many studies have shown the feasibility of using white rot fungi to remove these contaminants. However, none of them have studied the degradation of several PhACs in real urban wastewater under non-sterile conditions, where mixtures of contaminants presents at low concentrations (ng L(-1) to μg L(-1)) as well as other active microorganisms are present. In this work, a batch fluidized bed bioreactor was used to study, for the first time, the degradation of PhACs present in urban wastewaters at their pre-existent concentrations under non-sterile conditions. Glucose and ammonium tartrate were continuously supplied as carbon and nitrogen source, respectively, and pH was maintained at 4.5. Complete removal of 7 out of the 10 initially detected PhACs was achieved in non-sterile treatment, while only 2 were partially removed and 1 of the PhACs analyzed increased its concentration. In addition, Microtox test showed an important reduction of toxicity in the wastewater after the treatment.

Hospital wastewater treatment by fungal bioreactor: removal efficiency for pharmaceuticals and endocrine disruptor compounds.

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 8185 μg in sterile treatment and 8426 μg 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.

Effects of compost stability and contaminant concentration on the bioremediation of PAHs-contaminated soil through composting

The objective of this study was to investigate the effect of two factors: the stability degree (0.37-4.55 mg O(2) g(-1) Organic Matter h(-1)) of different composts derived from the organic fraction of municipal solid wastes and the concentration of a complex mixture of PAHs including fluorene, phenanthrene, anthracene, fluoranthene, pyrene and benzo(a)anthracene in the bioremediation of soil. The two factors were systematically studied applying central composite design methodology. The obtained results demonstrated that compost stability degree was particularly important during the first stage of the process. Stable composts enhanced the levels of degradation in soil-compost mixture and a degradation rate of 92% was achieved in this period, but only 40% was degraded with the least stable compost. The PAHs concentration was also important during the process, since the degradation rates increased with the increase in the PAHs concentration. Moreover, all the individual PAHs demonstrated a notable decrease in their concentrations after the incubation period, but pyrene was degraded to lower levels in some treatments compared to others PAHs.

Metabolites from the biodegradation of triphenylmethane dyes by Trametes versicolor or laccase

The feasibility of degrading triphenylmethane dyes by Trametes versicolor and laccase has been investigated for the following dyes: Acid Fuchsin, Brilliant Green 1, Basic Fuchsin, Methyl Green or Acid Green 16. The toxicity level of triphenylmethane dyes is linked to their basic character, but significant detoxification is obtained when there is biodegradation. Identification of enzymatic degradation products by (1)H NMR made it possible to propose a general rule for the laccase attack on triphenylmethane compounds. The enzyme completely degrades the molecular part of the canonical resonance substructures of dyes, because no N-substituted, mono-N and di-N,N substituted p-amine aromatic residues seem to be wholly degraded. No enzymatic degradation is observed in the cases of either the non-substituted or trisubstituted-N,N,Np-amine aromatic residues. On the other hand, for all the dyes tested, no aromatic residues are detected after fungal treatment; this means that T. versicolor is more capable of performing further degradation than is laccase. The results of this study demonstrated that compounds with a triphenylmethane structure can be degraded by T. versicolor even if they are highly toxic. The enzyme laccase plays an important role in the attack on the structure and a general rule for predicting which products would be obtained after the enzymatic treatment is suggested.

The relationships between biomass concentration, determined by a capacitance-based probe, rheology and morphology of Saccharopolyspora erythraea cultures

Saccharopolyspora erythraea was grown in submerged culture at two agitation speeds, 750 and 1000 rpm, on a soluble medium with glucose as the main carbon source. There was good agreement during the growth phase between a commercial capacitance probe and biomass concentrations as determined by dry weight measurements. However, later in the cultures when the biomass concentration was declining, the two methods diverged due to part of the biomass solids becoming inactive lysed cells. The higher agitation speed resulted in more fragmentation of the mycelia and a lower viscosity, but the output from the biomass probe was unaffected by these changes.

Olive oil mill waste waters decoloration and detoxification in a bioreactor by the white rot fungus Phanerochaete flavido-alba.

Olive oil mill wastewater (OMW) is produced as waste in olive oil extraction. With the purpose of treating this highly polluting waste, a number of experiments were conducted in a laboratory‐scale bioreactor with the white rot fungus Phanerochaete flavido‐alba ( P. flavido‐alba). It is known that this fungus is capable of decolorizing OMW in static or semistatic cultures at Erlenmeyer scale and at 30 °C. The objective of this work was to prove that P. flavido‐alba could decolorize OMW in submerged cultures and that it is capable of reducing OMW toxicity at room temperature (25 °C) and in a laboratory‐scale bioreactor. In the experiments conducted, manganese peroxidase (MnP) and laccase enzymes were detected; however, unlike other studies, lignin peroxidase was not found to be present. Decoloration obtained after treatment was 70%. The reduction of aromatic compounds obtained was 51%, and the toxicity of the culture medium was reduced by up to 70%. We can therefore state that P. flavido‐alba is capable of reducing important environmental parameters of industrial effluents and that prospects are positive for the use of this process at a larger scale, even when working at room temperature.

Degradation of selected agrochemicals by the white rot fungus Trametes versicolor

Use of agrochemicals is a worldwide practice that exerts an important effect on the environment; therefore the search of approaches for the elimination of such pollutants should be encouraged. The degradation of the insecticides imiprothrin (IP) and cypermethrin (CP), the insecticide/nematicide carbofuran (CBF) and the antibiotic of agricultural use oxytetracycline (OTC) were assayed with the white rot fungus Trametes versicolor. Experiments with fungal pellets demonstrated extensive degradation of the four tested agrochemicals, at rates that followed the pattern IP>OTC>CP>CBF. In vitro assays with laccase-mediator systems showed that this extracellular enzyme participates in the transformation of IP but not in the cases of CBF and OTC. On the other hand, in vivo studies with inhibitors of cytochrome P450 revealed that this intracellular system plays an important role in the degradation of IP, OTC and CBF, but not for CP. The compounds 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (DCCA) and 3-phenoxybenzoic acid (PBA) were detected as transformation products of CP, as a result of the breakdown of the molecule. Meanwhile, 3-hydroxycarbofuran was detected as a transformation product of CBF; this metabolite tended to accumulate during the process, nonetheless, the toxicity of the system was effectively reduced. Simultaneous degradation of CBF and OTC showed a reduction in toxicity; similarly, when successive additions of OTC were done during the slower degradation of CBF, the fungal pellets were able to degrade both compounds. The simultaneous degradation of the four compounds successfully took place with minimal inhibition of fungal activity and resulted in the reduction of the global toxicity, thus supporting the potential use of T. versicolor for the treatment of diverse agrochemicals.

Adsorption Step in the Biological Degradation of a Textile Dye

This research documents the removal of the dye Gris Lanaset G from aqueous solutions by fungal pellets. Adsorption of the dye by dead biomass pellets of Trametes versicolor was determined and compared with dye removal by enzymatic degradation. Six kinetic equations were fitted to the experimental adsorption data obtained. The results indicate that kinetics such as the Elovich equation, which considers that the rate‐controlling step is the diffusion of the dye molecules, show the best fit. Nonlinear Langmuir and Freundlich equations were also fitted into the adsorption data, and it can be concluded that the adsorption equilibrium can be interpreted by the Langmuir isotherm. Adsorption plays an important role in the process of the elimination of color from textile wastewater, although not all of the elimination is due to this physical process when the microorganism is active. The removal of color (around 90%) with active microorganisms is greater than that obtained with the adsorption process.

A comparative life cycle assessment of two treatment technologies for the Grey Lanaset G textile dye: biodegradation by Trametes versicolor and granular activated carbon adsorption

PurposeThe aim of this study is to use life cycle assessment (LCA) to compare the relative environmental performance of the treatment using Trametes versicolor with a common method such as activated carbon adsorption. This comparison will evaluate potential environmental impacts of the two processes. This work compiles life cycle inventory data for a biological process that may be useful for other emergent biotechnological processes in water and waste management. LCA was performed to evaluate the use of a new technology for the removal of a model metal-complex dye, Grey Lanaset G, from textile wastewater by means of the fungus T. versicolor. This biological treatment was compared with a conventional coal-based activated carbon adsorption treatment to determine which alternative is preferable from an environmental point of view.Materials and methodsThe study is based on experimental research that has tested the novel process at the pilot scale. The analysis of the biological system ranges from the production of the electricity and ingredients required for the growth of the fungus and ends with the composting of the residual biomass from the process. The analysis of the activated carbon system includes the production of the adsorbent material and the electricity needed for the treatment and regeneration of the spent activated carbon. Seven indicators that measure the environmental performance of these technologies are included in the LCA. The indicators used are climate change, ozone depletion, human toxicity, photochemical oxidant formation, terrestial acidification, freshwater eutrophication, marine eutrophication, terrestrial ecotoxicity, freshwater ecotoxicity, marine ecotoxicity, metal depletion and fossil depletion.ResultsThe results show that the energy use throughout the biological process, mainly for sterilisation and aeration, accounts for the major environmental impacts with the inoculum sterilisation being the most critical determinant. Nevertheless, the biological treatment has lower impacts than the physicochemical system in six of these indicators when steam is generated directly on site. A low-grade carbon source as an alternative to glucose might contribute to reduce the eutrophication impact of this process.ConclusionsThe LCA shows that the biological treatment process using the fungus T. versicolor to remove Grey Lanaset G offers important environmental advantages in comparison with the traditional activated carbon adsorption method. This study also provides environmental data and an indication of the potential impacts of characteristic processes that may be of interest for other applications in the field of biological waste treatment and wastewater treatment involving white-rot fungi.

Non conventional biological treatment based on Trametes versicolor for the elimination of recalcitrant anticancer drugs in hospital wastewater

This work presents a study about the elimination of anticancer drugs, a group of pollutants considered recalcitrant during conventional activated sludge wastewater treatment, using a biological treatment based on the fungus Trametes versicolor. A 10-L fluidized bed bioreactor inoculated with this fungus was set up in order to evaluate the removal of 10 selected anticancer drugs in real hospital wastewater. Almost all the tested anticancer drugs were completely removed from the wastewater at the end of the batch experiment (8 days) with the exception of Ifosfamide and Tamoxifen. These two recalcitrant compounds, together with Cyclophosphamide, were selected for further studies to test their degradability by T. versicolor under optimal growth conditions. Cyclophosphamide and Ifosfamide were inalterable during batch experiments both at high and low concentration, whereas Tamoxifen exhibited a decrease in its concentration along the treatment. Two positional isomers of a hydroxylated form of Tamoxifen were identified during this experiment using a high resolution mass spectrometry based on ultra-high performance chromatography coupled to an Orbitrap detector (LTQ-Velos Orbitrap). Finally the identified transformation products of Tamoxifen were monitored in the bioreactor run with real hospital wastewater.