Influence of the feedstock material on the compost maturity, stability and reactivity

Compost samples from different origins have been characterized in order to obtain information about their composition, humic-like substances content, maturity and stability. The composts used in the present study were obtained from manure (CAP), algae (CA), domestic waste (VCRU), sewage sludge (CT) and animal waste (CE). Different techniques have been used to gather physical-chemical parameters of the raw composts, their equilibrium solutions and the extracted humic-like substances. The analysis of the parameters collected in the characterization process allowed to stablish the degree of maturity and stability of the composts. Results indicate that the compost originated from algae exhibits the highest degree of maturity. Also, metal complexation was analyzed in the CE compost with the aim of assessing the contribution of the different fractions of dissolved organic matter.0366_RES2VALHUM_1_P - Valorização de resíduos orgânicos: produção de substâncias húmicas, cofinanciada pelo Fundo Europeu de Desenvolvimento regional (FEDER) através do Programa INTERREG V-A Espanha-Portugal (POCTEP) 2014-2020

Comparison of cadmium binding by humic and fulvic acids extracted from compost samples of different feedstock

Compost is a bio-sustainable material produced by the controlled decomposition of the organic wastes. Composting can be employed for the urban organic waste treatment in alternative to incineration or landfill disposal [1]. The properties of compost are closely related to the presence of humic-like substances (HS). Both fulvic acids (FA) and humic acids (HA) contain a significant amount of carboxylic acids and phenolic groups that are responsible for some of their properties like solubility and ability to complex metal ions [2]. In the scope of the project Res2ValHum [3], composts produced from different feedstock were analysed and compared regarding the ability of the FA and the HA extracts to bind Cd2+. The free cadmium ion concentration was measured using the electroanalytical technique AGNES (absence of gradients and Nernstian equilibrium stripping) [4]. The cadmium binding by FA and HA extracts of two compost samples: compost of algae (CA) and compost of sludge sewage (CSS) is illustrated in Figure 1. Results indicate that the extent of the binding of cadmium by FA is similar despite the nature of the compost. In opposition, the HA extracts from the algae compost exhibit a larger capacity to bind cadmium ion in comparison to the extracted from the sludge sewage compost. These results indicate that the nature of the feedstock seem to affect more the structure of the HA (in comparison to the FA) formed during the composting process. The chemical characterization of these extracts by different analytical techniques are in course in order to fully understand the referred effect.0366_RES2VALHUM_1_P - Valorização de resíduos orgânicos: produção de substâncias húmicas, cofinanciada pelo Fundo Europeu de Desenvolvimento regional (FEDER) através do Programa INTERREG V-A Espanha-Portugal (POCTEP) 2014-202

Comparison of cadmium binding by humic and fulvic acids extracted from two composts of different origin

Composting has been proven to be an environmentally friendly process for urban organic waste, that can represent an opportunity for new uses under the circular economy framework. The binding of cadmium to fulvic-like and humic-like acids extracted from compost of algae and urban residues were evaluated, and the results show significant differences. The fulvic and humic acids from algae compost bind cadmium more efficiently than those from urban residues compost. Furthermore, data from humic acids from both composts display significantly higher ability to bind to cadmium than both their corresponding fulvic acids and the generic soil extracted humic matter.  Cooperation Program Interreg V-A Spain-Portugal (POCTEP) 2014-2020 and the European Union through the European Regional Development Fund -FEDER within the scope of the project «RES2VALHUM -Valorization of Organic Waste: Production of Humic Substances» (0366_RES2VALHUM_1_P).The authors want to thank LIPOR for the supply of COUR sample. Members of the USC are also grateful to CRETUS Strategic Partnership (ED431E 2018/01) co-funded by FEDER and the Galician Competitive Research Group GRC ED431C/12.Members of the Department of Chemistry are also grateful toCenter of Chemistrythrough projects UID/QUI/00686/2016 and UID/QUI/00686/2019 (CQUM) funded by Foundation for Science and Technology (FCT, Portugal

Characterization of organic matter at different stages of a composting process

The characterization of the organic matter from raw organic wastes, unmatured compost and maturated compost was performed by different techniques: gravimetric, FTIR-ATR, TGA and from the ability of their extracts to bind Cd2+ (evaluating the free cadmium ion by AGNES). Although the amount of humic-like and fulvic-like acids did not change significantly, the structure and properties of the organic matter changed with composting and maturation. These changes resulted in an increase of the stability of the organic material toward thermal decomposition and in an increase of the capacity to bind cadmium.0366_RES2VALHUM_1_P - Valorização de resíduos orgânicos: produção de substâncias húmicas, cofinanciada pelo Fundo Europeu de Desenvolvimento regional (FEDER) através do Programa INTERREG V-A Espanha-Portugal (POCTEP) 2014-2020

Thermoelectric properties of topological chains coupled to a quantum dot

Topological one-dimensional superconductors can sustain zero energy modes protected by diferent kinds of symmetries in their extremities. Observing these excitations in the form of Majorana fermions is one of the most intensive quests in condensed matter physics. We are interested in another class of one-dimensional topological systems in this work, namely topological insulators. Which present symmetry-protected end modes with robust properties and do not require the low temperatures necessary for topological superconductivity. We consider a device in the form of a single electron transistor coupled to the simplest kind of topological insulators, namely chains of atoms with hybridized sp orbitals. We study the thermoelectric properties of the device in the trivial, non-trivial topological phases and at the quantum topological transition of the chains. We show that the device’s electrical conductance and the Wiedemann–Franz ratio at the topological transition have universal values at very low temperatures. The conductance and thermopower of the device with diatomic sp-chains, at their topological transition, give direct evidence of fractional charges in the system. The former has an anomalous low-temperature behavior, attaining a universal value that is a consequence of the double degeneracy of the system due to the presence of zero energy modes. On the other hand, the system can be tuned to exhibit high values of the thermoelectric fgure of merit and the power factor at high temperatures.Campus San Juan de Luriganch

Sensitivity of South American tropical forests to an extreme climate anomaly

The tropical forest carbon sink is known to be drought sensitive, but it is unclear which forests are the most vulnerable to extreme events. Forests with hotter and drier baseline conditions may be protected by prior adaptation, or more vulnerable because they operate closer to physiological limits. Here we report that forests in drier South American climates experienced the greatest impacts of the 2015–2016 El Niño, indicating greater vulnerability to extreme temperatures and drought. The long-term, ground-measured tree-by-tree responses of 123 forest plots across tropical South America show that the biomass carbon sink ceased during the event with carbon balance becoming indistinguishable from zero (−0.02 ± 0.37 Mg C ha −1 per year). However, intact tropical South American forests overall were no more sensitive to the extreme 2015–2016 El Niño than to previous less intense events, remaining a key defence against climate change as long as they are protected

Xylanase Production by Talaromyces amestolkiae Valuing Agroindustrial Byproducts

In general, agroindustrial byproducts can be easily assimilated by several microorganisms due to their composition, which is rich in carbohydrates. Therefore, they could be appropriate for use as raw materials in a sustainable refinery concept, including the production of hydrolytic enzymes with industrial applicability. In this work, xylanase production by the filamentous fungi Talaromyces amestolkiae in submerged culture was evaluated using five agroindustrial byproducts, namely, wheat bran, citrus pulp, rice bran, peanut skin, and peanut shell. Firstly, the aforementioned byproducts were characterized in terms of cellulose, xylan, lignin, and extractives. Next, production studies were performed, and wheat bran generated the highest enzymatic activity (5.4 U·mL−1), probably because of its large amount of xylan. Subsequently, a factorial design was performed to evaluate the independent variables yeast extract, wheat bran, K2HPO4, and pH, aiming to improve the variable response, xylanase activity. The condition that promoted the highest production, 13.02 U·mL−1 (141% higher than the initial condition), was 20 g·L−1 wheat bran, 2.5 g·L−1 yeast extract, 3 g·L−1 K2HPO4, and pH 7. Thus, industrial byproducts with a high content of xylan can be used as a culture medium to produce xylanase enzymes with a Talaromyces strain through an economical and sustainable approach

Effect of Elderberry (Sambucus nigra L.) Extract Supplementation in STZ-Induced Diabetic Rats Fed with a High-Fat Diet

Elderberry (Sambucus nigra L.) lipophilic and polar extract dietary supplementation effects were evaluated according to diabetes management indices, using an in vivo model. A research pipeline was constructed, that ranged from extract preparation, partial chemical characterization and toxicity evaluation, to examining the elderberry extract dietary supplementation effects on biofluid and tissues. Extracts toxicity was screened using an Aliivibrio fischeri bioluminescence model. A concentration of up to 60 mg/L was selected, and rat doses for oral supplementation were computed applying the interspecies correlation between A. fischeri and rats. Wistar type 2 diabetic rats, induced by streptozotocin (STZ), were fed a high-fat diet and supplemented for 4 weeks at doses of 190 and 350 mg/kg body weight/day of lipophilic and polar extract, respectively. As far as we know, lipophilic elderberry extract supplementation was assessed for the first time, while polar extract was administrated at higher doses and for a shorter period compared to previous studies, aiming to evaluate subacute supplementation effects. The polar extract modulated glucose metabolism by correcting hyperglycemia, while the lipophilic extract lowered insulin secretion. Both extracts lowered insulin resistance, without remarkable alterations to hematological indices, sera lipids and sera and tissular trace element homeostasis. In conclusion, elderberries are a potential source of bioactive compounds for formulations to be used as co-adjuvants in diabetes management

Sensitivity of South American tropical forests to an extreme climate anomaly

NERC Knowledge Exchange Fellowship (NE/V018760/1) to E.N.H.C.The tropical forest carbon sink is known to be drought sensitive, but it is unclear which forests are the most vulnerable to extreme events. Forests with hotter and drier baseline conditions may be protected by prior adaptation, or more vulnerable because they operate closer to physiological limits. Here we report that forests in drier South American climates experienced the greatest impacts of the 2015–2016 El Niño, indicating greater vulnerability to extreme temperatures and drought. The long-term, ground-measured tree-by-tree responses of 123 forest plots across tropical South America show that the biomass carbon sink ceased during the event with carbon balance becoming indistinguishable from zero (−0.02 ± 0.37 Mg C ha−1 per year). However, intact tropical South American forests overall were no more sensitive to the extreme 2015–2016 El Niño than to previous less intense events, remaining a key defence against climate change as long as they are protected.Publisher PDFPeer reviewe