The Autocatalytic Chemical Reaction of a Soluble Biopolymer Derived from Municipal Biowaste.

The paper discusses the perspectives of further implementation of the autocatalytic properties of a soluble biopolymer (SBP) derived from municipal biowastes for the realisation of a biorefinery producing value-added bio-products for consumer use. The reaction of an SBP and water is reported to cause the depolymerisation and oxidation of the pristine SBP organic matter with the formation of carboxyl-functionalised polymers having lower molecular weight and CO2. These findings demonstrate the oxidation of the SBP via water, which could only occur through the production of O and OH radicals catalysed by the SBP. According to the adopted experimental plan, the anaerobic digestate supplied by an Italian municipal biowaste treatment plant was hydrolysed in pH 13 water at 60 °C. The dry product was re-dissolved in plain water at pH 10 and used as a control against the same solution with hydrogen peroxide at 0.1-3 H2O2 moles per SBP carbon mole added. The control and test solutions were kept at room temperature, in the dark or in a climatic chamber under irradiation with simulated solar light, until the pH of the solutions remained constant. Afterwards, the solutions were processed to recover and analyse the crude soluble products. The present work reports the results obtained for the control solution and for the test solutions treated in the presence and absence of H2O2, with and without pH control, in the dark and under irradiation with simulated solar light.

Mild Chemical Treatment of Unsorted Urban Food Wastes.

Municipal biowastes are conventionally treated by assessed anaerobic and aerobic fermentation to produce biogas, anaerobic digestate, and compost. Low-temperature hydrolysis and the oxidation of the digestate and compost, which are still at the experimental stage, are known to yield water-soluble value-added chemical specialities for use in different sectors of the chemical industry and in agriculture. The present paper reports the application of the two chemical reactions to the biowastes before fermentation. The products obtained in this manner are compared with those obtained from the chemical reactions applied to the fermented biowastes. Based on the experimental results, the paper discusses the expected environmental and economic benefits of the above chemical processes and products in comparison with the products obtained by other known biotechnologies for the valorisation of biomass as a feedstock for the biobased chemical industry. The results point out that a sustainable biowaste-based refinery that produces biofuel and biobased chemicals may be developed by integrating chemical and fermentation technologies.

Bioherbicidal activity of a germacranolide sesquiterpene dilactone from Ambrosia artemisiifolia L.

Ambrosia artemisiifolia L. (common ragweed) is an invasive plant whose allelopathic properties have been suggested by its field behaviour and demonstrated through phytotoxicity bioassays. However, the nature of the molecules responsible for the allelopathic activity of common ragweed has not been explored. The main objective of this study was to identify the phytotoxic molecules produced by A. artemisiifolia. A preliminary investigation has indicated that a methanol extract of A. artemisiifolia completely inhibited the germination of cress and radish. Semi-preparative fractionation of the methanol extract allowed separating of phytotoxic fraction which contained a single compound. The structure of this compound was elucidated by liquid chromatography-mass spectrometry (LC-MS)/MS, high-resolution mass spectral, nuclear magnetic resonance, and Fourier transform infrared spectra as sesquiterpene lactone isabelin (C15H16O4). The effect of pure isabelin was tested on four different weed species, confirming the inhibitory activity of molecule. The results indicate directions for the future studies about herbicidal specific activity of isabelin, as pure molecule or in the crude extract, as a potential candidate for biological weed control.

Processed vs. non-processed biowastes for agriculture: effects of post-harvest tomato plants and biochar on radish growth, chlorophyll content and protein production.

The aim of this work was to address the issue of processed vs. non-processed biowastes for agriculture, by comparing materials widely differing for the amount of process energy consumption. Thus, residual post harvest tomato plants (TP), the TP hydrolysates obtained at pH 13 and 60 °C, and two known biochar products obtained by 650 °C pyrolysis were prepared. All products were characterized and used in a cultivation of radish plants. The chemical composition and molecular nature of the materials was investigated by solid state 13C NMR spectrometry, elemental analysis and potentiometric titration. The plants were analysed for growth and content of chlorophyll, carotenoids and soluble proteins. The results show that the TP and the alkaline hydrolysates contain lignin, hemicellulose, protein, peptide and/or amino acids moieties, and several mineral elements. The biochar samples contain also similar mineral elements, but the organic fraction is characterized mainly by fused aromatic rings. All materials had a positive effect on radish growth, mainly on the diameter of roots. The best performances in terms of plant growth were given by miscanthus originated biochar and TP. The most significant effect was the enhancement of soluble protein content in the plants treated with the lowest energy consumption non processed TP. The significance of these findings for agriculture and the environment is discussed.

Determination of forchlorfenuron in fruits by solid phase or QuECHERS extraction and LC-UV or LC/MS/MS.

Forchlorfenuron, N-(2-chloro-4-pyridinyl)-N'-phenylurea, is a plant growth regulator used to increase the size of kiwifruit, apples, table grapes, and peaches and to promote increased yields of potatoes, rice, and wheat. This study reports the comparison of the performances of two extraction methods [Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) and SPE] and two analytical methods (LC-UV and a LC/MS/MS) when determining forchlorfenuron in apples, kiwis, and grapes. Both extraction methods gave recoveries of forchlorfenuron from fruits >70%. The QuEChERS method was cheaper, safer, and less time-consuming than the SPE method and can be recommended for routine analysis. The LOQ was 2 and 10 microg/kg for the LC/MS/MS and LC-UV analysis, respectively. The LOD was 1 and 5 microg/kg for the LC/MS/MS and LC-UV analysis, respectively. The sensitivity of the LC-UV analysis was adequate to measure residue levels five times lower than the maximum residue limit (MRL) of the product. The QuEChERS and SPE methods were applied to monitoring the persistence of forchlorfenuron in field-treated kiwis, and it was found that the residual concentration was already much lower than the MRL 7 days after treatment.

Organically modified clays as binders of fumonisins in feedstocks.

This study reports an investigation on the ability of organically modified clays to bind mycotoxins, fumonisins B1 (FB1) and B2 (FB2). Organically modified clays are commercia materials prepared from natural clays, generally montmorillonite, by exchanging the inorganic cation with an ammonium organic cation. A screening experiment conducted on 13 organically modified clays and 3 nonmodified clays, used as controls, has confirmed that the presence of an organic cation in the clay interlayer promoted the adsorption of both fumonisins. On the basis of the results of the screening test, four modified clays and a Na-montmorillonite were selected for the determination of the adsorption kinetics and isotherms. On all the tested materials adsorption took place within one hour of contact with fumonisins solutions. Adsorption isotherms have pointed out that the modified clays exhibited a higher adsorptive capacity than the unmodified clay. It was also demonstrated that, notwithstanding the reduced structural difference between FB1 and FB2, they were differently adsorbed on the modified clays. Addition of 2% modified clays to contaminated maize allowed a reduction of more than 70% and 60% of the amount of FB1and FB2 released in solution. Although in vivo experiments are required to confirm the effectiveness of the organically modified clays, these preliminary results suggest that these materials are promising as fumonisins binders.

Organo-clays and nanosponges for acquifer bioremediation: adsorption and degradation of triclopyr.

To avoid the problem of groundwater contamination, mitigation techniques have been proposed that consist of creating barriers made of suitable materials that can facilitate the adsorption and degradation of the pollutants. This study aims at evaluating the capacity of two organo-clays (Dellite 67 G and Dellite 43 B) and one nanosponge to adsorb the herbicide, triclopyr. Triclopyr was chosen because it is a good example of a moderately mobile, leacheable molecule. The rate of degradation of the molecule in the soil, both with and without the presence of the materials under examination, was also determined. Both the organo-clays adsorbed more than 90% of the herbicide. The nanosponge and the soil adsorbed less than 10% triclopyr. When the soil was added with the two organoclays, adsorption increased to 92%. When added to the soil, the materials accelerated the degradation of triclopyr. The half-life in soil was 30 days, whereas in soil with Dellite 67 G and Dellite 43 B it was 10 and 6 days respectively. The addition of the nanosponge to the soil decreased the half life by 50%. These results lead us to suggest that they be used in creating reactive barriers for the remediation of soils and aquifers.

Buffer strip effect on terbuthylazine, desethyl-terbuthylazine and S-metolachlor runoff from maize fields in Northern Italy.

The effectiveness of a 6 m wide vegetative buffer strip for reducing runoff of S-metolachlor, terbuthylazine and desethyl-terbuthylazine was studied in 2007-2008 in Northern Italy. Two cultivated fields, with and without the buffer strip, were compared. Residues of the chemicals were investigated in runoff water collected after runoff events and their dissipation in the soil was studied. The highest concentration of the chemicals in water occurred in samples collected from the unbuffered field at the first runoff events. Losses of terbuthylazine and S-metolachlor in runoff waters were particularly high in 2007 (2.6% and 0.9% of the amount applied, respectively). Soil half-life of terbuthylazine and S-metolachlor ranged between 12.1 and 8.9 days and 16 and 7 days, respectively. The presence of desethyl-terbuthylazine was related to parent compound degradation. The buffer strip allowed an important reduction of chemical content in water (> 90%), in particular during the first runoff events.

Dissipation of propanil and 3,4 dichloroaniline in three different rice management systems.

This study focused on the dissipation of propanil and 3,4 dichloroaniline (3,4 DCA) over time in the soil, field water, inlet water, and outlet water of paddy fields under three management systems: conventional water seeding (CON), conventional water seeding with supplied liquid manure (LMA), and dry seeding (DRY). Propanil dissipation in water was also investigated under laboratory conditions. The field study was conducted from 2004 to 2006 at Vercelli, northern Italy. Propanil and 3,4 DCA showed rapid dissipation in water and soil environments both in the field and in the laboratory. Under controlled conditions, chemical hydrolysis was not detected for either compounds for up to 100 d at pHs of 5, 7, and 9. In the laboratory, the half-life of propanil in irrigation water was 1.1 d; its half-life in soil was routinely measured at <1.0 d (between 0.17 and 1.77 d). 3,4 DCA was found to persist much longer. Measured in all three study years at 50 d after treatment, its concentration ranged between 44 µg kg (CON) and 140 µg kg (DRY). Propanil and 3,4 DCA concentrations in paddy water were particularly high in samples collected at 4 d (2004) and 2 d (2005) after treatment. Maximum concentrations were 54.4 µg L (CON) for propanil (2005) and 113.7 µg L (LMA) for 3,4 DCA (2004). The concentrations of propanil and 3,4 DCA in inlet water were never above 1.1 and 0.3 µg L, respectively, whereas the highest concentration of each compound in outlet water was in samples collected first after treatment in 2005 and 2006. Both chemicals dissipated rapidly in all the soil-water environments but displayed no important differences among the three management systems. In conclusion, propanil and 3,4 DCA did not persist longer in paddy fields. A risk of water network contamination by these compounds may occur only early after herbicide spraying. A water-holding period after herbicide spraying may reduce this risk.

Changes in chemical and biological parameters during co-composting of anaerobically digested sewage sludges with lignocellulosic material.

This study reports a pilot experiment of composting of anaerobically digested sewage sludges deriving from the production of biogas in a wastewater treatment plant. Two composting piles (about 15 m(3) each) were prepared by mixing 50% and 30% (v/v) sludges with lignocellulosic material. The composting process was monitored through determination of the main physicochemical properties. The stability of the composts was assessed by determination of the respiration index and dehydrogenase activity. The collected data indicated that, at both sludges concentrations, the process produced a compost suitable for agricultural applications as far as the physicochemical properties were concerned. On the other hand, in the pile containing 50% sludges, the maximum temperature of the thermophilic phase was lower than the temperature required (55°C) to ensure the sanitization of the compost. The germination and growth indexes of Lepidium sativum indicated the lack of phytotoxicity of the final materials. The suitability of the composts as field improvers and horticultural substrates has been attested through plant bioassays conducted on maize and chrysanthemum.

Evaluation of the field dissipation of fungicides and insecticides used on fruit bearing trees in northern Italy.

The dissipation of the fungicides captan, cyprodinil, fludioxonil, dithianon, and tebuconazole and of the insecticides chlorpyrifos, fenitrothion, and malathion was studied, following a single treatment of different cultivars of pears, apples, and peaches. The study was conducted in northern Italy, over two successive growing seasons (2004 and 2005). The treatments were performed by the farmers involved, in line with their usual practice. At various time intervals from treatment to harvest, representative samples of fruit were collected and analyzed for pesticide residues. In some cases, concentrations lower than the maximum residue levels (MRLs) were found immediately after treatment. In all trials a rapid decline in pesticide concentrations was observed leading to residues at harvest greatly below the MRLs.

Removal of fenhexamid and pyrimethanil from aqueous solutions by clays and organoclays.

The ability of a sodium montmorillonite (CLONa) and two commercial available organoclays having interlayer organic cations possessing different functional groups (CLO20A and CLO30B) was investigated for adsorbing two pesticides namely fenexamid (FEX) and pyrimethanyl (PMT). The two organoclays displayed a higher affinity with the pesticides than the unmodified clay, but the improvement in adsorption capacity varied according to the characteristics of the pesticide and the interlayer organic cation. FEX was adsorbed to a greater extent than PMT by both organoclays, which may be due to the higher hydrophobicity of FEX thereby indicating considerable hydrophobic interaction between the adsorbent/adsorbate systems. Our findings may find application in the removal of water-soluble pesticides from aquifers.

Effectiveness of control strategies against Botrytis cinerea in vineyard and evaluation of the residual fungicide concentrations.

This investigation was undertaken to test different control strategies against Botrytis cinerea vineyards. Two commercial vineyards, "Barbera" and "Moscato," located in Piedmont (Northern Italy) were divided into seven plots and treated with different combinations of fungicides including fenhexamid, pyrimethanil, fludioxonil + cyprodinil, iprodione, and boscalid, a new carboxamide compound. An integrated strategy including a chemical (pyrimethanil) and a biocontrol agent (Trichoderma spp. t2/4ph1) was also included. At harvest, the percentage of bunches and berries attacked by B. cinerea and the concentration of the chemical fungicides were determined. All the pesticide residues at harvest were below the maximum residue level (MRL), except when two applications of pyrimethanil per season were applied. Boscalid was the most effective active ingredient against B. cinerea among the tested chemicals. When boscalid application was followed by a treatment with pyrimethanil, its efficacy was similar to that shown by two treatments of pyrimethanil. However, this second strategy was not feasible due to the risks of resistance development in the pathogen and to the residue accumulation as indicated by the analysis.

Fate and degradation of triasulfuron in soil and water under laboratory conditions.

The behavior and fate of triasulfuron (TRS) in water and soil systems were examined in laboratory studies. The degradation of TRS in both buffer solution and soil was highly pH-sensitive. The rate of degradation could be described with a pseudo first-order kinetic and was much faster at pH 4 than at pH 7 and 9. Aqueous hydrolysis occurred by cleavage of the sulfonylurea bridge to form 2-(2-chloroethoxy) benzenesulfonamide (CBSA) and [(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] (AMMT). AMMT was unstable in aqueous solutions in any pH condition but it degraded more quickly at pH 4 and 9. CBSA did not degrade in aqueous solutions or in enriched cultures but it underwent a quick degradation in the soil. The rates of TRS degradation in sterile and non-sterile soils were similar, suggesting that microorganisms played a minimal role in the breakdown process. This hypothesis is supported by the results of studies on the degradation of TRS by enriched cultures during which the molecule underwent a prevalently chemical degradation.

The effect of isabelin, a sesquiterpene lactone from Ambrosia artemisiifolia on soil microorganisms and human pathogens.

Ambrosia artemisiifolia L. (common ragweed) is an invasive weed, which is well known for the strong allergenic effect of its pollen as well as for its invasiveness and impact in crop fields (e.g. causing yield losses). This species produces a broad range of sesquiterpenoids. In recent years, new bioactive molecules have been discovered in this plant, e.g. isabelin, a sesquiterpene dilactone. The bioactivity of isabelin has been already demonstrated on allergy-related receptors and its inhibitory effect on seeds of various plant species. Isabelin was tested for potential antimicrobial effects by using a selection of soil-borne bacteria and fungi and three human pathogens as model organisms. For the majority of microorganisms tested, no antimicrobial activity of isabelin was observed. However, isabelin revealed strong antimicrobial activity against the Gram-positive soil bacterium Paenibacillus sp. and against the Gram-positive, multidrug-resistant Staphylococcus aureus. The observed inhibitory activity of isabelin can enlighten the importance to study similar compounds for their effect on human pathogens and on soil and rhizosphere microorganisms.

Evaluation of the bioavailability of the herbicide prosulfocarb through adsorption on soils and model soil colloids, and through a simple bioassay.

Adsorption isotherms of prosulfocarb were determined on soils with different physicochemical properties. The extent of adsorption increased with the organic carbon content, but the results also suggested the involvement of some inorganic soil surfaces. In order better to understand the role of each soil surface, adsorption-desorption isotherms were determined on model soil colloids consisting of a soil humic acid, a montmorillonite, a synthetic aluminium hydroxide and their associations. The highest adsorption was observed on the humic acid, but it was also confirmed that the montmorillonite interacted with prosulfocarb. In contrast, the aluminium hydroxide was not active and its association with montmorillonite provoked a decrease in adsorption compared with montmorillonite alone. Except for humic acid, the highest adsorption took place on the ternary association montmorillonite-aluminium hydroxide-humic acid. On each surface tested, the adsorption was largely reversible and decreased at increasing pH. The herbicidal activity of prosulfocarb was tested by the determination of the germination and growth of a typical weed, Lolium multiflorum Lam, in contact with prosulfocarb solutions at different concentrations. The herbicide did not prevent the germination of the seeds but inhibited the growth of the roots and leaves. The same test was performed in the presence of the ternary system to evaluate the influence of adsorption on the plant bioavailability. It was concluded that the presence of an adsorptive surface reduced the herbicidal activity and that the simple bioassay proposed could be useful in predicting the extent of adsorption in a given soil.

Cultivating Chlorella vulgaris and Scenedesmus quadricauda microalgae to degrade inorganic compounds and pesticides in water.

This work evaluates the possibility of cultivating Scenedesmus quadricauda and Chlorella vulgaris microalgae in wastewater from the hydroponic cultivation of tomatoes with the aim of purifying the water. S. quadricauda and C. vulgaris were also used in purification tests carried out on water contaminated by the following active ingredients: metalaxyl, pyrimethanil, fenhexamid, iprodione, and triclopyr. Fifty-six days after the inoculum was placed, a reduction was found in the concentration of nitric nitrogen, ammonia nitrogen, and soluble and total phosphorus. The decrease was 99, 83, 94, and 94 %, respectively, for C. vulgaris and 99, 5, 88, and 89 %, respectively, for S. quadricauda. When the microalgae were present, all the agrochemicals tested were removed more quickly from the water than from the sterile control (BG11). The increase in the rate of degradation was in the order metalaxyl > fenhexamid > iprodione > triclopyr > pyrimethanil. It was demonstrated that there was a real degradation of fenhexamid, metalaxyl, triclopyr, and iprodione, while in the case of pyrimethanil, the active ingredient removed from the substrate was absorbed onto the cells of the microalgae. It was also found that the agrochemicals used in the tests had no significant effect on the growth of the two microalgae. The experiment highlighted the possibility of using cultivations of C. vulgaris and S. quadricauda as purification systems for agricultural wastewater which contains eutrophic inorganic compounds such as nitrates and phosphates and also different types of pesticides.

Cinosulfuron: chemical and biological degradability, adsorption and dissipation in flooded paddy field sediment.

Cinosulfuron is a sulfonylurea herbicide largely used in the extensive cultures of flooded rice in North Italy. The degradation of cinosulfuron has been investigated in sterile aqueous solutions at 30 degrees C at different pH values. It was rapidly degraded at acidic pH (half-lives 3, 9 and 43 days at pH 4, 5 and 6, respectively) while the half-life was > 1 year at pH 7 and 9. Two degradation products formed by cleavage of the sulfonylurea bridge were identified by LC-MS. Degradation by selected mixed microbial cultures tested in aerobic and anaerobic conditions was very slow and attributable to chemical hydrolysis due to the acidic pH of the cultural broths. Degradation took place in freshly collected rice field water treated for two years with cinosulfuron but, in this case also, chemical hydrolysis prevailed over microbial degradation. In contrast, in flooded sediment simulating the paddy field environment, the dissipation rate of cinosulfuron was higher than expected from chemical hydrolysis according to the pH of the system, indicating the involvement of soil microflora. Although the herbicide exhibited a reduced affinity for the sediment surfaces demonstrated by the low value of the K(f) Freundlich coefficient (0.87 on a micromolar basis), the rapid dissipation observed in the simulated paddy field should prevent its leaching to ground water.

Moniliformin analysis in maize samples from North-West Italy using multifunctional clean-up columns and the LC-MS/MS detection method.

A fast clean-up method has been developed to purify maize extracts and to detect moniliformin (MON) in maize samples from North-West Italy over a four-year period (2008-2011). The method is based on the use of MycoSep® 240 Mon clean-up columns (Romer Labs®). Samples were extracted using acetonitrile/water (84:16, v/v), and the extracts were purified with previously described clean-up columns. The liquid chromatography-tandem mass spectrography (LC-MS/MS) analysis has been carried out by means of hydrophilic interaction chromatography (HILIC), combined with negative electrospray mass spectrometry. The method has a recovery of 76-91% (relative standard deviation, RSD%: 6-14%), a limit of detection (LOD) of 1 µg kg⁻¹ and a limit of quantification (LOQ) of 4 µg kg⁻¹. Naturally contaminated maize (108 samples) was analysed for MON content. The average percentages of positive samples was 93% with the following ranges (µg kg⁻¹): 33-2606 (2008);

Refuse derived soluble bio-organics enhancing tomato plant growth and productivity.

Municipal bio-refuse (CVD), containing kitchen wastes, home gardening residues and public park trimmings, was treated with alkali to yield a soluble bio-organic fraction (SBO) and an insoluble residue. These materials were characterized using elemental analysis, potentiometric titration, and 13C NMR spectroscopy, and then applied as organic fertilizers to soil for tomato greenhouse cultivation. Their performance was compared with a commercial product obtained from animal residues. Plant growth, fruit yield and quality, and soil and leaf chemical composition were the selected performance indicators. The SBO exhibited the best performance by enhancing leaf chlorophyll content, improving plant growth and fruit ripening rate and yield. No product performance-chemical composition relationship could be assessed. Solubility could be one reason for the superior performance of SBO as a tomato growth promoter. The enhancement of leaf chlorophyll content is discussed to identify a possible link with the SBO photosensitizing properties that have been demonstrated in other work, and thus with photosynthetic performance.