Can white-rot fungi be a real wastewater treatment alternative for organic micropollutants removal? A review

Micropollutants are a diverse group of compounds that are detected at trace concentrations and may have a negative effect on the environment and/or human health. Most of them are unregulated contaminants, although they have raised a concern in the scientific and global community and future regulation might be written in the near future. Several approaches have been tested to remove micropollutants from wastewater streams. In this manuscript, a focus is placed in reactor biological treatments that use white-rot fungi. A critical review of white-rot fungal-based technologies for micropollutant removal from wastewater has been conducted, several capabilities and limitations of such approaches have been identified and a range of solutions to overcome most of the limitations have been reviewed and/or proposed. Overall, this review argues that white-rot fungal reactors could be an efficient technology to remove micropollutants from specific wastewater streams

Re-parametrisation of Adel-wheat allows reducing the experimental effort to simulate the 3D development of winter wheat

Eds. Risto Sievänen, Eero Nikinmaa, Christophe Godin, Anna Lintunen & Pekka NygrenA parameterisation of wheat architecture was developed, having high flexibility to simulate contrasted genotypes and growth conditions with a reasonably low number of parameters. Field measurements at 4-5 dates allowed to simulate crops from emergence to maturity with a good agreement between simulated and measured ground cover and GAI. Dynamics of leaf angles were shown to impact strongly ground cover

Removal of water pollutants by adsorption on activated carbon prepared from olive-waste cakes and by biological treatment using ligninolytic fungi

Se utilizan diferentes procesos para el tratamiento de las aguas residuales. Sin embargo, estas tecnologías son ineficaces, generan productos secundarios o son demasiado caras. El objetivo principal de esta tesis es la eliminación de diversos contaminantes del agua, incluyendo metales, tintes y productos farmacéuticos mediante dos tecnologías. La primera consiste en un tratamiento físico-químico de adsorción sobre carbón activo preparado a partir de un resido de la industria agroalimentaria. El segundo se trata de un tratamiento biológico con hongos. En cuanto a la adsorción sobre carbón activo, en una primera etapa se consideran aspectos tales como la preparación del adsorbente, su caracterización y el estudio del impacto ambiental asociado a su producción. Para la preparación de carbón activo se realiza la activación química a partir de orujo de oliva, utilizando ácido fosfórico como agente deshidratante. Se varían los parámetros principales del proceso para optimizar las condiciones de la activación. El carbón activo preparado, se caracteriza teniendo en cuenta sus propiedades de adsorción, su estructura química y su morfología. Los resultados muestran que el adsorbente más eficaz es el que se obtiene bajo las siguientes condiciones: una concentración igual a 60% de H3PO4, una relación de impregnación de 1,75, y una temperatura de pirolisis de 450°C. El adsorbente preparado en estas condiciones presenta buenas características en comparación con los que se encuentran en la literatura. Para minimizar el impacto ambiental, ciertas modificaciones podrían incorporarse en el proceso de preparación del adsorbente tales como la recuperación del gas derivado de la etapa de pirolisis y su utilización como fuente de energía, y la recuperación de ácido fosfórico después de lavar el carbón activado. Después de establecer las condiciones óptimas se evalúa la eficiencia del carbón activo para la eliminación de los contaminantes inorgánicos y orgánicos. Para los metales, cogiendo Cu2 + como un modelo, los ensayos de adsorción en columna muestran la alta capacidad del carbón activo para reducir KMnO4 en óxido insoluble de manganeso (MnO2) que impregna la superficie del adsorbente, cuya presencia mejora significativamente los resultados de la adsorción de Cu2+ sobre el carbón activo. En cuanto a los contaminantes orgánicos, el estudio muestra la eficacia del carbón activado para eliminar colorantes de los efluentes sintéticos y reales y productos farmacéuticos de soluciones de compuestos puros y formando parte de una mezcla de fármacos. En la mayoría de los casos los modelos de Langmuir y pseudo-primero orden presentan el mejor ajuste para la isoterma y la cinética, respectivamente. La temperatura afecta la adsorción de colorantes, sin embargo, la variación de pH no tiene ninguna influencia. Al contrario que en la adsorción de los fármacos. En cuanto al proceso biológico adaptado, se ha comprobado el potencial de tres hongos ligninolíticos (Trametes versicolor, Ganoderma lucidum y Irpex lacteus) para la decoloración de un colorante de la industria de curtidos. Los resultados indican que Trametes versicolor es la mejor cepa tanto en términos de extensión y rapidez en la decoloración. Tanto en procesos en discontinuo como en discontinuos repetidos en un reactor fluidizado por pulsos de aire y con reuso de biomasa muestra que la capacidad de decoloración del hongo es del 86-89% y no disminuye durante los discontinuos repetidos a pesar de la baja actividad enzimática detectada. Se ha evidenciado que la lacasa es una enzima involucrada en la biodegradación y que el fenómeno de adsorción que ocurre en la biomasa fúngica. Finalmente, la combinación del tratamiento mediante hongos y la adsorción en adsorbentes de bajo coste puede ser una estrategia adecuada para depurar efluentes complejos.Different processes are used for the treatment of wastewaters. However, they are either frequently ineffective, or they generate secondary products or worse, they are too expensive. The main objective of this dissertation is the removal of various contaminants in water including metals, dyes and pharmaceuticals products via two environmentally- friendly technologies. The first consists in a physico-chemical treatment- by adsorption on activated carbon prepared from olive-waste cakes. The second is about a biological treatment using white-rot fungi. First, the adsorbent preparation, its characterization and the study of the environmental impact associated with its production are considered. Chemical activation of the feedstock olive-waste cakes, using phosphoric acid as dehydrating agent, is adopted for activated carbon preparation and main process parameters (such as acid concentration, impregnation ratio, temperature of pyrolysis step) are varied to optimize the best conditions. The activated carbon prepared under the optimal conditions is then fully characterized considering its adsorption properties as well as its chemical structure and morphology. The results show that the most efficient adsorbent is that obtained under the following optimal conditions: an acid concentration equal to 60% H3PO4, an impregnation ratio of 1.75, and a pyrolysis temperature of 450 °C. The adsorption characteristics of the adsorbent prepared under such conditions presents good characteristics compared with the previous reports for activated carbon in the literature. To minimize the environmental impact, certain modifications could be incorporated in the process of adsorbent preparation such as recovery of the gas derived from the pyrolysis step, its reuse as an energy source, and the recovery of phosphoric acid after activated carbon washing. After establishing the optimal conditions, the efficiency of the optimal activated carbon for the removal of inorganic and organic pollutants is then evaluated. For heavy metals, considering the adsorption of Cu2+ ions as a model, column adsorption tests show the high capacity of the activated carbon to reduce KMnO4 into insoluble manganese (IV) oxide (MnO2) which impregnated the sorbent surface. The results also indicate that the adsorption of Cu2+ can be significantly improved by the presence of MnO2 fixed on activated carbon. Concerning the organic pollutants, the study shows the effectiveness of the activated carbon to remove dyes from individual and real effluents and pharmaceutical products from single and mixture solutions. Many models are used to understand the adsorption behavior and in the most cases Langmuir and pseudo-second order models present the best fit for the isotherm and kinetics, respectively. Temperature is found to affect the adsorption of dyes, however, the pH variation has no influence. The opposite case is found for drugs adsorption. Regarding the biological process adapted, the potential of three white-rot fungi (WRF) (Trametes versicolor, Ganoderma lucidum and Irpex lacteus) to decolorize the commercial tannery dye − Black Dycem – is investigated in solid and liquid media. The results indicate that Trametes versicolor is the best strain both in terms of extent and rapidity of decolorization. The experiment, performed in single and repeated batches in an air-pulsed bioreactor with biomass reuse of the fungus Trametes versicolor, shows that the decolorization capability of the fungus does not decrease during the repeated batches and the fungus is able to remove 86−89% of the dye despite the low enzyme activity detected. The results also show that the biodegradation mechanism plays a noticeable role in the decolorization process of the dye by means of laccase activity in addition to the adsorption phenomenon occurring on the fungal surface. Finally a combination of fungal treatment and adsorption on low cost adsorbents could be a suitable strategy to remove pollutants from complex effluents

Plasticity of winter wheat architecture modulated by sowing date and plant population density and its effect on Septoria tritici epidemics

Les pratiques culturales modifient l'architecture des couverts de manière à augmenter ou diminuer le développement des épidémies mais les processus mis en jeu sont complexes ; des modèles mécanistes simulant l'interaction entre plante et pathogène devraient aider à les clarifier. Les modèles de Plantes Virtuelles, qui permettent de décrire explicitement la structure tridimensionnelle de la plante, semblent particulièrement prometteurs pour exprimer les effets de l'architecture de la plante sur le développement des épidémies. L'objectif de cette étude est d'examiner la possibilité de simuler l'effet de l'architecture des plantes sur le développement de la maladie en utilisant un modèle Plante Virtuelle. Dans ce travail, nous nous intéressons au pathosystème blé-Septoria tritici, dans lequel l'architecture joue un rôle important. En effet, les spores de Septoria tritici sont propagées par les éclaboussures de pluie depuis les feuilles infectées du bas du couvert vers les nouvelles feuilles saines. Notre travail s'est appuyé sur un modèle pré-existant d'épidémie de la septoriose, Septo3D. L'architecture du blé a été étudiée pour une gamme de densités et de date de semis. Les différences de phyllochrone entre traitements ont été dans une gamme susceptible de modifier le développement de la septoriose. Ces variations ont été représentées par un modèle descriptif qui tient compte du nombre de feuilles final et de la photopériode. Une description détaillée des variables d'architecture à l'échelle des organes et du couvert a fourni une documentation originale et complète sur la plasticité de l'architecture du blé. Ces données ont été utilisées pour paramétrer la description du blé dans Septo3D. Globalement, les traitements étudiés ont conduit à de fortes différences de la densité de végétation au cours du temps. Les dynamiques de développement de la septoriose ont été suivies pour trois traitements de densités contrastées. Les cinétiques de la maladie simulées par le modèle étaient conformes aux mesures expérimentales. Bien que, l'approche nécessite davantage de validation, les résultats confirment que l'approche Plante Virtuelle apporte un nouvel éclairage sur les processus et les caractéristiques des plantes qui impactent les épidémies. En conclusion, nous proposons quelques perspectives en vue de nouvelles applications et améliorations de l'approche.Agronomic practices modify crop architecture in ways that may facilitate or hamper disease development. The processes involved are complex and mechanistic models simulating plant-pathogen interaction should help clarifying them. Virtual Plants, i.e. models in which the three-dimensional structure of the plant is explicitly described, appear specially promising to express the effects of the plant architecture on the epidemic development. The objective of this study is to examine the ability to simulate the effect of plant architecture on disease development using a Virtual Plant model.The work focuses on the pathosystem wheat-Septoria tritici, in which architecture plays an important role because spores of Septoria are propagated from infected leaves to upper healthy leaves by rain splash. We build on a pre-existing model of Septoria epidemics, Septo3D. Wheat architecture was examined for a range of sowing date and density treatments. Differences of phyllochron between treatments were in a range sufficient to likely modify epidemic development; they were well represented by a descriptive model depending on photoperiod and final leaf number. A detailed description of architectural variables at the organ and canopy scale provided an original and comprehensive documentation of the plastic response of wheat, which was used for parameterising the wheat description in Septo3D. Overall, the investigated treatments resulted in strong differences in the time course of vegetation density. Septoria dynamics were monitored in a subset of three treatments of contrasted densities. Simulated disease kinetics were consistent with field measurements. Although, the approach needs further validation, results support that virtual plant modelling provides new insights into the processes and plant traits that impact epidemics. We conclude with prospects for further improvements and applications

Plasticité de l'architecture du blé d'hiver modulée par la densité et la date de semis et son effet sur les épidémies de Septoria tritici

Agronomic practices modify crop architecture in ways that may facilitate or hamper disease development. The processes involved are complex and mechanistic models simulating plant-pathogen interaction should help clarifying them. Virtual Plants, i.e. models in which the three-dimensional structure of the plant is explicitly described, appear specially promising to express the effects of the plant architecture on the epidemic development. The objective of this study is to examine the ability to simulate the effect of plant architecture on disease development using a Virtual Plant model.The work focuses on the pathosystem wheat-Septoria tritici, in which architecture plays an important role because spores of Septoria are propagated from infected leaves to upper healthy leaves by rain splash. We build on a pre-existing model of Septoria epidemics, Septo3D. Wheat architecture was examined for a range of sowing date and density treatments. Differences of phyllochron between treatments were in a range sufficient to likely modify epidemic development; they were well represented by a descriptive model depending on photoperiod and final leaf number. A detailed description of architectural variables at the organ and canopy scale provided an original and comprehensive documentation of the plastic response of wheat, which was used for parameterising the wheat description in Septo3D. Overall, the investigated treatments resulted in strong differences in the time course of vegetation density. Septoria dynamics were monitored in a subset of three treatments of contrasted densities. Simulated disease kinetics were consistent with field measurements. Although, the approach needs further validation, results support that virtual plant modelling provides new insights into the processes and plant traits that impact epidemics. We conclude with prospects for further improvements and applications.Les pratiques culturales modifient l'architecture des couverts de manière à augmenter ou diminuer le développement des épidémies mais les processus mis en jeu sont complexes ; des modèles mécanistes simulant l'interaction entre plante et pathogène devraient aider à les clarifier. Les modèles de Plantes Virtuelles, qui permettent de décrire explicitement la structure tridimensionnelle de la plante, semblent particulièrement prometteurs pour exprimer les effets de l'architecture de la plante sur le développement des épidémies. L'objectif de cette étude est d'examiner la possibilité de simuler l'effet de l'architecture des plantes sur le développement de la maladie en utilisant un modèle Plante Virtuelle. Dans ce travail, nous nous intéressons au pathosystème blé-Septoria tritici, dans lequel l'architecture joue un rôle important. En effet, les spores de Septoria tritici sont propagées par les éclaboussures de pluie depuis les feuilles infectées du bas du couvert vers les nouvelles feuilles saines. Notre travail s'est appuyé sur un modèle pré-existant d'épidémie de la septoriose, Septo3D. L'architecture du blé a été étudiée pour une gamme de densités et de date de semis. Les différences de phyllochrone entre traitements ont été dans une gamme susceptible de modifier le développement de la septoriose. Ces variations ont été représentées par un modèle descriptif qui tient compte du nombre de feuilles final et de la photopériode. Une description détaillée des variables d'architecture à l'échelle des organes et du couvert a fourni une documentation originale et complète sur la plasticité de l'architecture du blé. Ces données ont été utilisées pour paramétrer la description du blé dans Septo3D. Globalement, les traitements étudiés ont conduit à de fortes différences de la densité de végétation au cours du temps. Les dynamiques de développement de la septoriose ont été suivies pour trois traitements de densités contrastées. Les cinétiques de la maladie simulées par le modèle étaient conformes aux mesures expérimentales. Bien que, l'approche nécessite davantage de validation, les résultats confirment que l'approche Plante Virtuelle apporte un nouvel éclairage sur les processus et les caractéristiques des plantes qui impactent les épidémies. En conclusion, nous proposons quelques perspectives en vue de nouvelles applications et améliorations de l'approche

Differences for traits associated with early N acquisition in a grain legume and early complementarity in grain legume-triticale mixtures

Early strategies of crop growth and N acquisition can be critical for determining competitive interactions between weeds and crops. Grain legumes and especially lupins are known to be poor competitors against weeds. Grain legumes are known to have low mineral soil N uptake abilities. However, inter-and intraspecific differences in N uptake ability in relation to below-ground traits have received little attention. Our objectives were (i) to measure differences among lupins for a set of traits associated with early growth and N acquisition; (ii) to examine how this variation compares to differences between lupin and a cereal, triticale, and (iii) to assess if mixing lupin with triticale provides a higher potential than does pure lupin regarding plant biomass and mineral soil N acquisition early in the crop cycle. Lupin (12 genotypes) and triticale plants were grown separately and in mixed species pairs in a replacement design for 1 and 2 months in three rhizotron experiments. Shoot and root biomass, root length, root expansion dynamics, N(2) fixation and mineral soil N uptake were measured. Differences among lupin species and genotypes regarding traits related to early growth and to mineral soil N uptake were observed, but all lupins demonstrated slow early growth and low ability to absorb mineral soil N compared to triticale. In lupin-triticale mixture, a contrast in early growth strategies between species induced a higher total soil mineral N uptake compared with pure lupin. Complementarity between lupin and triticale persisted during the second month, when interactions began. This complementarity may allow for reduced competition between species, favouring higher triticale biomass production than in pure triticale, without compromising lupin growth

Assessing the effect of canopy architecture as affected by sowing density on epidemics using a virtual wheat plant model coupled with a Septoria tritici epidemic model

International audienceno abstrac

Modelling the effect of wheat canopy architecture as affected by sowing density on Septoria tritici epidemics using a coupled epidemic-virtual plant model

International audienceBackground and Aims The relationship between Septoria tritici, a splash-dispersed disease, and its host is complex because of the interactions between the dynamic plant architecture and the vertical progress of the disease. The aim of this study was to test the capacity of a coupled virtual wheat-Septoria tritici epidemic model (Septo3D) to simulate disease progress on the different leaf layers for contrasted sowing density treatments.Methods A field experiment was performed with winter wheat 'Soissons' grown at three contrasted densities. Plant architecture was characterized to parameterize the wheat model, and disease dynamic was monitored to compare with simulations. Three simulation scenarios, differing in the degree of detail with which plant variability of development was represented, were defined.Key Results Despite architectural differences between density treatments, few differences were found in disease progress; only the lower-density treatment resulted in a slightly higher rate of lesion development. Model predictions were consistent with field measurements but did not reproduce the higher rate of lesion progress in the low density. The canopy reconstruction scenario in which inter-plant variability was taken into account yielded the best agreement between measured and simulated epidemics. Simulations performed with the canopy represented by a population of the same average plant deviated strongly from the observations.Conclusions It was possible to compare the predicted and measured epidemics on detailed variables, supporting the hypothesis that the approach is able to provide new insights into the processes and plant traits that contribute to the epidemics. On the other hand, the complex and dynamic responses to sowing density made it difficult to test the model precisely and to disentangle the various aspects involved. This could be overcome by comparing more contrasted and/or simpler canopy architectures such as those resulting from quasi-isogenic lines differing by single architectural traits

Plasticity of winter wheat modulated by sowing date, plant population density and nitrogen fertilisation: Dimensions and size of leaf blades, sheaths and internodes in relation to their position on a stem

International audienceMathematical models to describe crop-environment interaction on organ scale need to take crop or plant architecture into account. Up to now, architectural plant models are largely descriptive and parameters need to be estimated for each species, cultivar and environment. Required measurements are extensive and time-consuming. Hence investigating morphological patterns and their modulation as a response to environmental conditions may help to reduce measurement efforts and to predict plant architecture in crop models. In this paper, we describe the plasticity of winter wheat - expressed as the dimensions and sizes of leaf blades, sheaths and internodes in relation to their position on a stem - under the climatic conditions of the Paris region. Results are discussed with respect to: (i) genotypic variability, (ii) inter-annual variability, (iii) sowing date and plant population density, (iv) Nitrogen fertilisation and (v) tiller rank. Eight wheat cultivars grown in the same season showed similar patterns of leaf and internodes dimensions in relation to their position on the stem. For the cultivar 'Soissons', main stem architecture at flowering was remarkably stable when similar growth conditions were reproduced in the different seasons. Increased plant population density yielded longer juvenile, but shorter adult leaf blades and sheaths. Earlier sowing led to an increase in the number of juvenile phytomers - growing before the onset of stem elongation - on the main stem, whereas the number of adult phytomers was almost identical. Further there were little differences in the size of leaf blades, sheaths and internodes between the main stem and axillary tillers. We found remarkable differences in the size of adult leaf blades and sheaths in different growing seasons, with different timing of nitrogen fertilisation and we discuss decreased availability of nitrogen in the soil in spring as a likely cause. Data presented here can be used to enlarge the understanding of wheat plasticity regarding the regulation of organ size by temperature, light, plant-available nitrogen and size-mediated effects towards a mechanistic modelling of these responses

Can white-rot fungi be a real wastewater treatment alternative for organic micropollutants removal? A review

Micropollutants are a diverse group of compounds that are detected at trace concentrations and may have a negative effect on the environment and/or human health. Most of them are unregulated contaminants, although they have raised a concern in the scientific and global community and future regulation might be written in the near future. Several approaches have been tested to remove micropollutants from wastewater streams. In this manuscript, a focus is placed in reactor biological treatments that use white-rot fungi. A critical review of white-rot fungal-based technologies for micropollutant removal from wastewater has been conducted, several capabilities and limitations of such approaches have been identified and a range of solutions to overcome most of the limitations have been reviewed and/or proposed. Overall, this review argues that white-rot fungal reactors could be an efficient technology to remove micropollutants from specific wastewater streams