A Coating Based on Bioactive Compounds from Streptomyces spp. and Chitosan Oligomers to Control Botrytis cinerea Preserves the Quality and Improves the Shelf Life of Table Grapes

Botrytis cinerea is the most harmful postharvest disease of table grapes. Among the strategies that can be envisaged for its control, the use of coatings based on natural products is particularly promising. The study presented herein focuses on the assessment of the antagonistic capacity of two Streptomyces species and their culture filtrates against B. cinerea. Firstly, the secondary metabolites were characterized by gas chromatography-mass spectrometry, with N1-(4-hydroxybutyl)-N3-methylguanidine acetate and 2R,3S-9-[1,3,4-trihydroxy-2-butoxymethyl]guanine acetate as the main compounds produced by S. lavendofoliae DSM 40217; and cyclo(leucyloprolyl) and cyclo(phenylalanylprolyl) as the most abundant chemical species for S. rochei DSM 41729. Subsequently, the capacity of S. lavendofoliae DSM 40217 and S. rochei DSM 41729 to inhibit the growth of the pathogen was tested in dual culture plate assays, finding 85-90% inhibition. In agar dilution tests, their culture filtrates resulted in effective concentration values (EC₉₀) in the 246-3013 μg·mL^-1 range. Upon the formation of conjugate complexes with chitosan oligomers (COS) to improve solubility and bioavailability, a synergistic behavior was observed, resulting in lower EC₉₀ values, ranging from 201 to 953 μg·mL^-1. Ex situ tests carried out on 'Timpson' and 'Red Globe' table grapes using the conjugate complexes as coatings were found to maintain the turgor of the grapes and delay the appearance of the pathogen by 10-15 days at concentrations in the 750-1000 µg·mL^-1 range. Hence, the conjugate complexes of COS and the selected Streptomyces spp. culture filtrates may be put forward as promising protection treatments for the sustainable control of gray mold.

Comparison of the Ammonia Trapping Performance of Different Gas-Permeable Tubular Membrane System Configurations

The technology of gas-permeable tubular membranes (GPMs) is promising in reducing ammonia emissions from livestock manure, capturing NH₃ in an acidic solution, and obtaining final products suitable for valorization as fertilizers, in line with the principles of the circular economy. This study aimed to evaluate the performance of several e-PTFE membrane systems with different configurations for the recovery of NH₃ released from pig slurry. Ten different configurations were tested: only a submerged membrane, only a suspended membrane in the same chamber, only a suspended membrane in an annex chamber, a submerged membrane + a suspended membrane in the same chamber, and a submerged membrane + a suspended membrane in an annex chamber, considering in each case the scenarios without and with agitation and aeration of the slurry. In all tests, sulfuric acid (1N H₂SO₄) was used as the NH₃ capture solution, which circulated at a flow rate of 2.1 L·h^-1. The results showed that NH₃-N removal rates ranged from 36-39% (for systems with a single submerged or suspended membrane without agitation or aeration of the slurry) to 70-72% for submerged + suspended GPM systems with agitation and aeration. In turn, NH₃-N recovery rates were found to be between 44-54% (for systems with a single membrane suspended in an annex compartment) and 88-91% (for systems based on a single submerged membrane). However, when choosing a system for farm deployment, it is essential to consider not only the capture and recovery performance of the system, but also the investment and operating costs (ranging from 9.8 to 21.2 €/kg N recovered depending on the selected configuration). The overall assessment suggests that the simplest systems, based on a single membrane, may be the most recommendable.

Evaluation of Different Capture Solutions for Ammonia Recovery in Suspended Gas Permeable Membrane Systems

Gas permeable membranes (GPM) are a promising technology for the capture and recovery of ammonia (NH3). The work presented herein assessed the impact of the capture solution and temperature on NH3 recovery for suspended GPM systems, evaluating at a laboratory scale the performance of eight different trapping solutions (water and sulfuric, phosphoric, nitric, carbonic, carbonic, acetic, citric, and maleic acids) at 25 and 2 °C. At 25 °C, the highest NH3 capture efficiency was achieved using strong acids (87% and 77% for sulfuric and nitric acid, respectively), followed by citric and phosphoric acid (65%) and water (62%). However, a remarkable improvement was observed for phosphoric acid (+15%), citric acid (+16%), maleic acid (+22%), and water (+12%) when the capture solution was at 2 °C. The economic analysis showed that water would be the cheapest option at any working temperature, with costs of 2.13 and 2.52 €/g N (vs. 3.33 and 3.43 €/g N for sulfuric acid) in the winter and summer scenarios, respectively. As for phosphoric and citric acid, they could be promising NH3 trapping solutions in the winter months, with associated costs of 3.20 and 3.96 €/g N, respectively. Based on capture performance and economic and environmental considerations, the reported findings support that water, phosphoric acid, and citric acid can be viable alternatives to the strong acids commonly used as NH3 adsorbents in these systems.

Pilot Plant for the Capture of Ammonia from the Atmosphere of Pig and Poultry Farms Using Gas-Permeable Membrane Technology

Gas-permeable membrane (GPM) technology is a possible solution to reduce ammonia (NH₃) emissions from livestock housing. This paper presents the results obtained with an NH₃-capture prototype based on the use of expanded polytetrafluoroethylene (ePTFE) membranes in real conditions in a gestating sow house and a free-range laying hen house, comparing them with the results obtained in controlled laboratory conditions for the same type of waste. The NH₃ present in the air of the livestock housing was captured by reaction with an acidic solution flowing inside the membranes. The periods of continuous operation of the pilot plant were 232 days at the pig farm and 256 days at the poultry farm. The NH₃ recovery rate at the end of those periods was 2.3 and 0.4 g TAN·m^-2·d^-1 in the pig and the poultry farms, respectively. The limiting factor for the capture process was the NH₃ concentration in the air, with the highest recovery occurring in the most concentrated atmosphere. Differences in NH₃ capture were observed between seasons and farms, with capture efficiencies of 1.62 and 0.33 g·m^-2·d^-1 in summer and 3.85 and 1.20 g·m^-2·d^-1 in winter for pig and poultry farms, respectively. The observed differences were mainly due to the higher ventilation frequency in the summer months, which resulted in a lower NH₃ concentration inside the houses compared to the winter months. This is especially important when considering the real applicability of this technology. The results obtained suggest that GPM technology holds promise for limiting NH₃ emissions from livestock housing with NH₃ ambient concentrations close to 20 ppm or as part of manure storage facilities, given that it allows for recovery of nitrogen in a stable and concentrated solution, which can be used as a fertilizer.

On the composition of gastroliths from broiler breeders

The purpose of this study was to ascertain the composition and origin of certain gastroliths or gizzard stones from broiler breeders (Gallus gallus domesticus). Fourier transform infrared spectroscopy (FTIR) and X-ray powder diffraction techniques were used as analysis tools. The main components resulted to be organic fibre and minerals referred to a pegmatite rock (quartz, feldspar albite and haematite) used as grit. Although the generally accepted purpose of gastroliths in chicken is the crushing and grinding of foodstuff in the ventriculus, the importance of mineral uptake from grit of iron and other essential elements such as Al, Ca, K, Cl, P, Ti, Mn, Mg, Cu, Zn and Zr (in ppm) as a secondary effect of the abrasion and dissolution of gastroliths should not be disregarded.

Hygienization and control of Diplodia seriata fungus in vine pruning waste composting and its seasonal variability in open and closed systems

After the ban on sodium arsenite, waste management alternatives to the prevalent burning method, such as the hygienization and biodegradation in solid phase by composting, are required for the pruned material from grapevines affected by various fungi. In this work the dynamics of a fungus associated with vine decay (Diplodia seriata) during the composting process of a mixture of laying hen manure and vine pruning waste (2:1w/w) have been investigated in an open pile and a discontinuous closed biodigester. Through the optimization of the various physical-chemical parameters, hygienization of the infected waste materials was attained, yielding class-A organo-mineral fertilizers. Nevertheless, important differences in the efficiency of each system were observed: whereas in the open pile it took 10days to control D. seriata and 35 additional composting days to achieve full inactivation, in the discontinuous biodigester the fungus was entirely inactivated within the first 3-7days. Finally, the impact of seasonal variability was assessed and summer temperatures shown to have greater significance in the open pile.

Estimation of PCB content in agricultural soils associated with long-term fertilization with organic waste

Polychlorinated biphenyl (PCB) pollution related to the use of organic waste as fertilizers in agricultural soils is a cause of major concern. In the study presented herein, PCB concentration was studied through a field trial conducted in two agricultural soils in the province of Palencia (Spain) over a 4-year period, assessing the impact of irrigation and of different types of organic waste materials. The amounts of organic waste added to the soil were calculated according to the nitrogen needs of the crop, and the concentration of PCBs was determined before and after the application of the organic waste. The resulting persistence of the total PCB content in the agricultural soils, compared with the PCB concentration in the original soils, ranged from 27% to 90%, with the lowest value corresponding to irrigated soils treated with municipal solid waste compost (MSWC) and the highest value to non-irrigated soils treated with composted sewage sludge (CSS). An estimate of the PCB content in agricultural soils after the application of organic waste materials until year 2050 was obtained, resulting in a value below 5 ng·g(-1), considered a background value for soils in sites far away from potential pollution sources.

Rhodamine B removal with activated carbons obtained from lignocellulosic waste

By-products from the wax production process from carnauba palm (leaves), from the extraction of oil from macauba seeds (endocarp) and from pine nut production (shell) have been assessed for activated carbon production, using H3PO4 or CaCl2 for their chemical activation. The resulting activated charcoals have been thoroughly characterized by elemental and thermal analysis, X-ray diffraction, infrared spectroscopy, electron scanning microscopy and N2 adsorption behavior. Subsequently, their adsorption capacity for the removal of rhodamine B (RhB) from aqueous solutions has been evaluated by studying different parameters: contact time, pH, adsorbent dose, initial dye concentration and solution temperature. The adsorption of RhB followed Freundlich's model in all cases. Kinetic studies indicate that the pseudo-second order model can be used for describing the dynamics of the adsorption process. Thermodynamic parameters have also been evaluated, indicating its endothermic and spontaneous nature. Finally, a preliminary analysis of the impact of cellulose content in the carbon precursor materials has been conducted, by using a mixture of native cellulose with one of the lignocellulosic materials.

Composting and vermicomposting experiences in the treatment and bioconversion of asphaltens from the Prestige oil spill

This work illustrates the effectiveness of composting and vermicomposting in degrading fuel-in-water emulsions from oil spills (chapapote), and the isolation of potentially useful microorganisms for its biodegradation. Firstly, an alternative to the biodegradation of asphaltens from the Prestige oil spill (still present in some chapapote rafts in the Cantabrian coast) by means of the application of composting techniques to a microbial partnership acclimated to fuel-oil is offered. Our aim is that, after a relatively short period of time, the microorganisms can obtain its source of carbon and energy from asphaltens. The addition of metabolic co-substrates, like cow bed and potato peelings, allows the fragmentation of complex compounds into smaller structures, susceptible to further degradation. Afterwards, a maturation of the compost by means of a treatment with earthworms (Eisenia foetida) is necessary. Thus, through the vermicomposting it will be possible to obtain a valued product, useful in the processes of ground amendment, with little presence of asphaltens and occluded polycyclic aromatic hydrocarbons, rich in humus, and with an important bacterial flora of Bacillus genera, so that it can be typical of co-activators and accelerating products in composting processes. Along with this article, we show some parameters that control the evolution of the compost products (evolved gases, acidity, temperature and humidity); the chemical and microbiological analytical results; and the germination assays of vermicomposting. Results reveal that by using microorganisms living in either earthworm intestines (Stenotrophomonas maltophilia) or vermiculture substrates (Scedosporium apiospermium), it is possible to degrade and to eliminate the polycyclic asphaltens into CO(2) and H(2)O, helped by evaporation, dissolution and/or photo-oxidation processes. The obtained end product has contents of interesting vegetal nutrients and, mainly, it displays very high germination indices.