BUSCADOR RECOLECTA

8 Páginas.-- 5 Figuras.-- 2 Tablas, The relationships between extracellular polymeric substances (EPS), soluble microbial product production, metal solubility, and methanogenic activity were investigated. The individual, and joint, toxic effects of nickel and cobalt on methanogenic consortia fed with glucose as model substrate were studied using biomethane potential assays. Cobalt was found to be less toxic to methanogens than nickel at each concentration tested, and the combined effects of Ni and Co on methane production in the bimetal experiment was higher than the sum of the effects of each metal alone. The protein content of EPS, and extracellular soluble protein fractions, decreased with increasing concentrations of total metals. Meanwhile, no significant change in response to metal stress was apparent for carbohydrate content of EPS or extracellular soluble carbohydrate. Decreasing protein content of EPS was accompanied by reduced methanogenic activity and an increase in the soluble metal fraction. The strong associations observed between these variables could be due to the critical role of EPS in protecting microbial cells against nickel and cobalt stress, possibly by capturing metal cations through their functional groups, thus reducing metal availability to the microbial cells in the methanogenic consortia underpinning the anaerobic digestion process., This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 861088. Antonio Serrano is grateful to the Economic Transformation, Industry, Knowledge and Universities Department of the Andalucia Autonomous Government for his Emergia fellowship (EMERGIA20_00114)., Peer reviewed

16 Páginas.-- 6 Figuras
Este trabajo es financiado por el proyecto M2ex “Exploiting metal-microbe applications to expand the circular economy”, cuyo Investigador Principal es el Dr. Fernando G. Fermoso (Instituto de la Grasa-CSIC), Introduction: Digestate originating from anaerobic digestion of non-source-separated organic fraction of municipal solid waste (OFMSW) is produced abundantly worldwide and generally discarded in landfills. However, it can be a valuable resource for many bioeconomy strategies as land restoration, only if a consolidated understanding of the contaminants’ presence and behaviour in digestate-amended soil is achieved. This study aimed to investigate the fate of trace metals, namely Zn, Cu, Pb, and Cr found in the digestate, along the soil profile after digestate application on soil, and the influence that other contaminants as pharmaceutical compounds can have on their behaviour in the soil system.

Methods: For that, a 90-day soil column experiment was conducted using a fine loamy sand soil topped with a layer of digestate-amended soil. Digestate-amended soil had a soil to digestate proportion of 14 to 1 (dry weight). Two experimental conditions were tested: soil amended with digestate, and soil amended with digestate spiked with the antidiabetic drug metformin. Soil samples were taken at 4 depths on days 1, 7, 21, 35 and 90, and total trace metals concentrations and fractionation were determined via atomic absorption spectroscopy.

Results: Results showed that Zn, Cu, Pb ad Cr initially present in the digestate were transferred from the digestate-amended soil layer to the underlying soil layer over time, although in low amounts. Nevertheless, no transfer was detected to the deeper soil layers. Trace metals in soil were predominantly in immobile and less bioavailable forms associated with clay and silicate mineral groups, whereas in the digestate-amended soil they were in more bioavailable forms, which could be related to metals’ migration in the soil layers below. Results also show that the presence of metformin had no influence on trace metal behaviour, giving insight also on possible interactions with other potentially present contaminants as microplastics.

Conclusion: The current study showed that OFMSW digestate can be a promising organic nutrient-rich matrix for land restoration even if it may contain high metals’ concentrations because low metal mobility along the soil profile can be expected., This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 861088., Peer reviewed

Exploiting metal-microbe applications to expand the circular economy (M2ex) GA no 861088, 1 Excel file, Digestate originating from anaerobic digestion of non-source-separated organic fraction of municipal solid waste (OFMSW) is produced abundantly worldwide and generally discarded in landfills. However, it can be a valuable resource for many bioeconomy strategies as land restoration, only if a consolidated understanding of the contaminants’ presence and behaviour in digestate-amended soil is achieved. This study aimed to investigate the fate of trace metals, namely Zn, Cu, Pb, and Cr found in the digestate, along the soil profile after digestate application on soil, and the influence that other contaminants as pharmaceutical compounds can have on their behaviour in the soil system. For that, a 90-day soil column experiment was conducted using a fine loamy sand soil topped with a layer of digestate-amended soil. Digestate-amended soil had a soil to digestate proportion of 14 to 1 (dry weight). Two experimental conditions were tested: soil amended with digestate, and soil amended with digestate spiked with the antidiabetic drug metformin. Soil samples were taken at 4 depths on days 1, 7, 21, 35 and 90, and total trace metals concentrations and fractionation was determined via atomic absorption spectroscopy. Results showed that Zn, Cu, Pb ad Cr initially present in the digestate were transferred from the digestate-amended soil layer to the underlying soil layer over time, although in low amounts. Nevertheless, no transfer was detected to the deeper soil layers. Trace metals in soil were predominantly in immobile and less bioavailable forms associated with clay and silicate mineral groups, whereas in the digestate-amended soil they were in more bioavailable forms, which could be related also to metals’ migration in the soil layers below. Results also show that the presence of metformin had no influence on trace metal behaviour, giving insight also on possible interactions with other potentially present contaminants as microplastics. The current study showed that OFMSW digestate can be a promising organic nutrient-rich matrix for land restoration even if it may contain high metals’ concentrations because low metal mobility along the soil profile can be expected., This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 861088., Peer reviewed

13 Páginas.-- · Figuras.-- 3 Tablas, Harnessing microbial capabilities for metal recovery from secondary waste sources is an eco-friendly and sustainable approach for the management of metal-containing wastes. Soluble microbial products (SMP) and extracellular polymeric substances (EPS) are the two main groups of extracellular compounds produced by microorganisms in response to metal stress that are of great importance for remediation and recovery of metals. These include various high-, and low, molecular weight components, which serve various functional and structural roles. These compounds often contain functional groups with metal binding potential that can attenuate metal stress by sequestering metal ions, making them less bioavailable. Microorganisms can regulate the content and composition of EPS and SMP in response to metal stress in order to increase the compounds specificity and capacity for metal binding. Thus, EPS and SMP represent ideal candidates for developing technologies for selective metal recovery from complex wastes. To discover highly metal-sorptive compounds with specific metal binding affinity for metal recovery applications, it is necessary to investigate the metal binding affinity of these compounds, especially under metal stressed conditions. In this review we critically reviewed microbial EPS and SMP production as a response to metal stress with a particular emphasis on the metal binding properties of these compounds and their role in altering metal bioavailability. Furthermore, for the first time, we compiled the available data on potential application of these compounds for selective metal recovery from waste streams., This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 861088., Peer reviewed

10 Páginas.-- 6 Figuras.-- 2 Tablas, Dosing trace metals into anaerobic digestors is proven to improve biogas production rate and yield by stimulating microorganisms involved in the metabolic pathways. Trace metal effects are governed by metal speciation and bioavailability. Though chemical equilibrium speciation models are well-established and widely used to understand metal speciation, the development of kinetic models considering biological and physicochemical processes has recently gained attention. This work proposes a dynamic model for metal speciation during anaerobic digestion which is based on a system of ordinary differential equations aimed to describe the kinetics of biological, precipitation/dissolution, gas transfer processes and, a system of algebraic equations to define fast ion complexation processes. The model also considers ion activity corrections to define effects of ionic strength. Results from this study shows the inaccuracy in predicting trace metal effects on anaerobic digestion by typical metal speciation models and the significance of considering non-ideal aqueous phase chemistry (ionic strength and ion pairing/complexation) to define speciation and metal labile fractions. Model results show a decrease in metal precipitation and increase in metal dissolved fraction and methane production yield with increase in ionic strength. Capability of the model to dynamically predict trace metal effects on anaerobic digestion under different conditions, like changing dosing conditions and initial iron to sulphide ratio, was also tested and verified. Dosing iron increases methane production and decreases hydrogen sulphide production. However, when iron to sulphide ratio is greater than 1, methane production decreases due to increase in dissolved iron which reaches inhibitory concentration levels., This research is supported by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 861088, Peer reviewed

12 Páginas.-- 8 Figuras.-- 1 Tabla, Trace metals (TM) are often added to anaerobic digestors (AD) to improve digestor performance and methane yield. Though numerous experimental studies are done to study TM effects, a model based on ADM1 will help plant operators in case of metal deprivation as there are analytical limitations in quantifying metal speciation which controls TM effects on AD. This study developed a complete dynamic model based on ADM1 with least and unavoidable model input information to study TM speciation and its influence on AD. In addition to the biochemical and gas stripping processes described in ADM1, the model introduced new physicochemical processes with effects of operational conditions like pH, temperature and ionic strength. The biogeochemical processes influencing TM speciation include microbial uptake, precipitation (sulphides, phosphates, carbonates), adsorption (onto biomass, soluble inerts and precipitates), inorganic complexation and organic complexation (with EDTA, VFAs, amino acids (AAs)). The model was tested under different scenarios: variable EDTA concentration and dosing form, variable substrate and variable ionic strength. Complexation of TMs with EDTA and AAs influences metal bioavailability and methane yield. Supplementing EDTA reduces TM dosing and dosing EDTA as metal-EDTA complex is more effective than supplementing metals and EDTA separately. TM-AA complexation depends on substrates as amino acid compounds vary with substrates. Ionic strength influences TM adsorption and precipitation processes and hence is an important operational parameter controlling the system like pH and temperature. The model has been compared to experimental data obtained from this study and has been successfully applied to predict cobalt deprivation in an anaerobic digestor., This research was supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 861088. Susan George and Maria Rosaria Mattei also acknowledge support from the National Recovery and Resilience Plan (NRRP), Mission 4 Component 2 Investment 1.4, funded by the European Union NextGenerationEU, Project Title National Research Center for Agricultural Technologies - Agritech, Project code CN00000022, Grant Assignment Decree No. 1032 adopted on 17/06/2022 by the Italian Ministry of University and Research (MUR)., Peer reviewed

7 Páginas.-- 4 Figuras.-- 2 Tablas, This study proposes an evaluation of the Diffusive Gradients in Thin films (DGT) technique to assess the labile fraction of trace metals and metalloids in anaerobic digestates. Experiments were performed in presence and absence of air to determine whether maintaining anaerobic conditions is mandatory during DGT deployments. A theoretically expected linear accumulation profile was observed for Fe, Mn, Ni, Mo, and As(III) in a manure-derived digestate and for Mn in distillery waste-derived digestate, whereas Al and Cu were detected without a consistent trend over time. The DGT technique can thus be used to evaluate the labile fraction of some trace elements in these digestates. The labile fraction of some elements was shown to evolve over 72 h when deployments were performed in the presence of air. We thus strongly recommend to systematically perform time-series deployments to identify and consider only the elements with a linear accumulation trend and to maintain anaerobic conditions., This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No 861088. The authors thanks Patrice Fondanèche for ICP-MS analysis and Emanuelle Ducloux for sampling., Peer reviewed

20 Páginas.-- 13 Figuras.-- 5 Tablas. Este trabajo es financiado por el proyecto M2ex “Exploiting metal-microbe applications to expand the circular economy”, cuyo Investigador Principal es el Dr. Fernando G. Fermoso (Instituto de la Grasa-CSIC), We propose a mathematical model to simulate the establishment and growth of a drinking water distribution system biofilm, focusing on the influence of ionic strength on bacterial adhesion and persistence of Legionella pneumophila. Specifically, we consider how ionic strength affects interaction energies during the initial phase of biofilm formation and we include the dependence of the attachment flux, modelled as a linear rate with respect to free floating cells, on it. The model also incorporates a novel necrotrophic kinetics to simulate the Legionella pneumophila metabolism. The biofilm is modelled as a 1D free boundary domain, and its evolution is governed by hyperbolic–parabolic PDEs. The initial attachment phase is modelled by considering a vanishing initial value for the free boundary. The model is investigated numerically highlighting the impact of the necrotrophic kinetic parameters, the influence of ionic strength on the initial stage of biofilm formation through bacterial attachment, and how variations in nutrient levels affect system dynamics. The numerical results demonstrate that: the ionic strength mainly governs bacterial adhesion for young biofilms and affects the biofilm ecology also in presence of a biocide; the necrotrophic metabolism of Legionella pneumophila favours its persistence in oligotrophic biofilms., This research has been supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 861088. This paper has been performed under the auspices of the G.N.F.M. of I.N.d.A.M., Peer reviewed

Exploiting metal-microbe applications to expand the circular economy (M2ex) GA no 861088, 12 pages, 3 tables, 7 images., The antidiabetic drug metformin and antiepileptic drug lamotrigine are contaminants of emerging concern that have been detected in biowaste-derived amendments and in the environment, and their fate must be carefully studied. This work aimed to evaluate their sorption behaviour on soil upon digestate application. Experiments were conducted on soil and digestate-amended soil as a function of time to study kinetic processes, and at equilibrium also regarding the influence of trace metals (Pb, Ni, Cr, Co, Cu, Zn) at ratio pharmaceutical/metal 1/1, 1/10, and 1/100. Pharmaceutical desorption experiments were also conducted to assess their potential mobility to groundwater. Results revealed that digestate amendment increased metformin and lamotrigine adsorbed amounts by 210% and 240%, respectively, increasing organic matter content. Metformin adsorption kinetics were best described by Langmuir model and those of lamotrigine by Elovich and intraparticle diffusion models. Trace metals did not significantly affect the adsorption of metformin in amended soil while significantly decreased that of lamotrigine by 12–39%, with exception for Cu2+ that increased both pharmaceuticals adsorbed amounts by 5 – 8%. This study highlighted the influence of digestate amendment on pharmaceutical adsorption and fate in soil, which must be considered in the circular economy scenario of waste-to-resource., This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 861088., Peer reviewed

12 Páginas.-- 7 Figuras.-- 3 Tablas.
Este trabajo es financiado por el proyecto M2ex “Exploiting metal-microbe applications to expand the circular economy”, cuyo Investigador Principal es el Dr. Fernando G. Fermoso (Instituto de la Grasa-CSIC), The antidiabetic drug metformin and antiepileptic drug lamotrigine are contaminants of emerging concern that have been detected in biowaste-derived amendments and in the environment, and their fate must be carefully studied. This work aimed to evaluate their sorption behaviour on soil upon digestate application. Experiments were conducted on soil and digestate-amended soil as a function of time to study kinetic processes, and at equilibrium also regarding the influence of trace metals (Pb, Ni, Cr, Co, Cu, Zn) at ratio pharmaceutical/metal 1/1, 1/10, and 1/100. Pharmaceutical desorption experiments were also conducted to assess their potential mobility to groundwater. Results revealed that digestate amendment increased metformin and lamotrigine adsorbed amounts by 210% and 240%, respectively, increasing organic matter content. Metformin adsorption kinetics were best described by Langmuir model and those of lamotrigine by Elovich and intraparticle diffusion models. Trace metals did not significantly affect the adsorption of metformin in amended soil while significantly decreased that of lamotrigine by 12-39%, with exception for Cu2+ that increased both pharmaceuticals adsorbed amounts by 5 - 8%. This study highlighted the influence of digestate amendment on pharmaceutical adsorption and fate in soil, which must be considered in the circular economy scenario of waste-to-resource., This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 861088., Peer reviewed

16 Páginas.-- 6 Figuras.-- 2 Tablas.
Este trabajo es financiado por el proyecto M2ex “Exploiting metal-microbe applications to expand the circular economy”, cuyo Investigador Principal es el Dr. Fernando G. Fermoso (Instituto de la Grasa-CSIC), Given the increasing pressure on water bodies, it is imperative to explore sustainable methodologies for wastewater treatment and reuse. The simultaneous presence of multiples contaminants in complex wastewater, such as the liquid effluents from biogas plants, can compromise biological treatment effectiveness for reclaiming water. Vertical subsurface flow constructed wetlands were established as low-cost decentralized wastewater treatment technologies to treat the liquid fraction of digestate from municipal organic waste with metals, antibiotics, and antibiotic resistance genes, to allow its reuse in irrigation. Twelve lab-scale planted constructed wetlands were assembled with gravel, light expanded clay aggregate and sand, testing four different treating conditions (liquid digestate spiked with oxytetracycline, sulfadiazine, or ofloxacin, at 100 μg/ L, or without dosing) during 3 months. Physicochemical parameters (pH, chemical oxygen demand (COD), nutrients, metals, and antibiotics), the microbial communities dynamics (through 16S high-throughput sequencing) and antibiotic resistance genes removal (qPCR) were monitored in influents and effluents. Systems removed 85.8%-96.9% of organic matter (as COD), over 98.1% of ammonium and phosphate ions, and 69.3%-99.4% of nitrate and nitrite ions, with no significant differences between the presence or absence of antibiotics. Removal of Fe, Mn, Zn, Cu, Pb and Cr exceeded 82% in all treatment cycles. The treatment also removed oxytetracycline, sulfadiazine and ofloxacin over 99%, and decreased intl1, tetA, tetW, sul1 and qnrS gene copies. Nonetheless, after 3 months of ofloxacin dosing, qnrS gene started being detected. Removal processes relied on high HRT (14 days) and various mechanisms including sorption, biodegradation, and precipitation. Microbial community diversity in liquid digestate changed significantly after treatment in constructed wetlands with a decrease in the initial Firmicutes dominance, but with no clear effect of antibiotics on the microbial community structure. Removals above 85% and 94% were observed for Streptococcus and Clostridium, respectively. Results suggest that vertical subsurface flow constructed wetlands were a suitable technology for treating the liquid digestate to reuse it in irrigation agricultural systems, contributing to the circular bioeconomy concept. However, a more profound understanding of effective wastewater treatment strategies is needed to avoid antibiotic resistance genes dissemination., The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Skłodowska-Curie Grant Agreement no. 861088., Peer reviewed

28 Páginas.-- 6 Figuras.-- 3 Tablas, Favourable effects of trace metals (TMs) on regulating anaerobic digestion (AD) performance are extensively utilised to improve methane yield. This study discusses a model-based approach to find out the best TM dosing strategies. The model has been applied to compare continuous, preloading, pulse dosing and in-situ loading. Simulations were also carried out to comprehend appropriate dosing form, dosing time and quantity of metals to be dosed. Model results show that the best way to dose TMs is repeated pulse dosing at low concentration levels in the optimum range with high frequency. Best dosing strategy for the system in this study was found to be 5 µM pulse loading at 5 days intervals as it gave maximum methane production and low effluent metal loss. Preferable dosing form depends on reactor configuration and this has been verified after model calibration with experimental data. Easily dissociable metal chlorides are ideal for continuous reactors., This research was supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 861088. Susan George and Maria Rosaria Mattei also acknowledge support from the National Recovery and Resilience Plan (NRRP), Mission 4 Component 2 Investment 1.4, funded by the European Union NextGenerationEU, Project Title National Research Center for Agricultural Technologies - Agritech, Project code CN00000022, Grant Assignment Decree No. 1032 adopted on 17/06/2022 by the Italian Ministry of University and Research (MUR)., Peer reviewed

21 Páginas.-- 8 Figuras.
Este trabajo es financiado por el proyecto M2ex “Exploiting metal-microbe applications to expand the circular economy”, cuyo Investigador Principal es el Dr. Fernando G. Fermoso (Instituto de la Grasa-CSIC), Panicum virgatum and Pennisetum alopecuroides, two non-food bioenergy crops, were evaluated for their capacity to phyto-manage trace metals (Pb, Zn, Ni, Fe, Mn, Co, Cr, and Cu) from municipal solid waste digestate after its application to a marginal soil. For that, 90-day vertical soil column mesocosm (columns with 0.6 × 0.2 m) experiments were carried out to assess 1) the impact of digestate application on the health of marginal soil, 2) plant effect on digestate-borne trace metals’ mobility along the soil profile (measuring total metal levels and fractionation in different soil layers by atomic absorption spectroscopy, and 3) plant growth performance and trace metal (Pb, Zn, and Cu) uptake capacity. The results showed that trace metals were mostly confined in the 0–0.2 m soil horizon over the course of the experimental period, migrating from the digestate-amended soil layer (0–0.1 m) to the layer underneath (0.1–0.2 m) within the first 21 days and remaining stable afterward. No evidence of the trace metals’ mobility to deeper soil layers was detected. Migration of trace metals was reduced in the presence of P. virgatum and P. alopecuroides, suggesting a phytoremediation (phytostabilization) effect. For both plant species, no trace metal accumulation in the roots was observed (bioconcentration factor <1), although both plants showed a potential for Zn translocation for aboveground tissues (translocation factor >1). The growth of both plants was positively affected by municipal solid waste digestate application, which also improved soil quality (increased concentration of total organic carbon and available phosphorus, as well as cation exchange capacity and water holding capacity)., The authors declare that financial support was received for the research, authorship, and/or publication of this article. This project has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no. 861088., Peer reviewed

22 Páginas.-- 16 Figuras.-- 5 Tablas.
Este trabajo es financiado por el proyecto M2ex “Exploiting metal-microbe applications to expand the circular economy”, cuyo Investigador Principal es el Dr. Fernando G. Fermoso (Instituto de la Grasa-CSIC), In this work, we propose a multidimensional continuum model for plasmid dissemination in biofilms via horizontal gene transfer. The model is formulated as a system of nonlocal partial differential equations derived from mass conservation laws and reaction kinetics principles. Biofilm is modelled as a homogeneous, viscous, incompressible fluid with a velocity given by Darcy's law. The model considers plasmid-carrying cells as distinct volume fractions and their vertical and horizontal gene transfer via conjugation and natural transformation. The model encompasses local detoxification of biofilm due to plasmid-borne resistance gene and its effect at the community scale. The equations are solved numerically and simulations are performed to investigate how transformation and conjugation regulate the dynamics and the ecology of plasmid spread in both a multidimensional and one-dimensional biofilm system. Model results are able to predict relevant experimentally observed results in plasmid spread, such as the respective intensity of different horizontal gene transfer mechanisms and the importance of selective pressure. Moreover, model results predict coexistence of plasmid-carrying and plasmid-free bacteria even in conditions when one should out-compete the other, offering a simple modelling explanation on global plasmid persistence in bacterial communities., This research has been supported by the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 861088., Peer reviewed