Effects of the application of microbiologically activated bio-based fertilizers derived from manures on tomato plants and their rhizospheric communities.

Bio-based fertilizers (BBFs) recovered from animal manure are promising products to optimise resources recovery and generate high agricultural yields. However, their fertilization value may be limited and it is necessary to enrich BBFs with microbial consortia to enhance their fertilization value. Three specific microbial consortia were developed according to the characteristics of three different BBFs produced from manure (bio-dried solid fraction, solid fraction of digestate and biochar) to enhance plant growth and product quality. A greenhouse pot experiment was carried out with tomato plants grown with microbiologically activated BBFs applied either as N-organic fertilizers or as an organic amendment. A next generation sequencing analysis was used to characterise the development of each rhizospheric community. All the activated BBFs gave enhanced tomato yields (fresh and dry weight) compared with the non-activated treatments and similar to, or higher than, chemical fertilization. Concerning the tomato fruits' organoleptic quality, lycopene and carotenoids concentrations were improved by biological activation. Metagenomic analysis points at Trichoderma as the main driver of the positive effects, with the effects of added bacteria being negligible or limited at the early stages after fertilization. In the context of the circular economy, the activated BBFs could be used to replace synthetic fertilisers, reducing costs and environmental burdens and increasing production.

Microbial community acclimatization enhances bioplastics biodegradation and biogas production under thermophilic anaerobic digestion.

This paper reports the results of a novel study of microbial acclimatization for bioplastics anaerobic degradation and conversion into biogas. Three sequential anaerobic digestion (AD) runs were carried out to favour microbial acclimatization to two different bioplastics, starch-based (SBS) and polyactic-acid (PLA). AD of SBS and PLA bioplastics was favoured by the acclimatization of the inoculum to the substrate after each run of AD. SBS conversion into biogas increased by 52 % (from 94 to 143 NL kgVS-1) and it was correlated with the enhanced growth of starch degrading bacteria such as Hydrogenispora, Halocella and Haloplasma. PLA anaerobic degradation increased by 97 % (from 395 to 779 NLbiogas kgVS-1) and it was related to the acclimatization of known PLA-degraders such as Tepidimicrobium, Methanothermobacter and Tepidanaerobacter. Microbial acclimatization appears a suitable and low-cost strategy to enhance bioplastics circularity by promoting their anaerobic biodegradation and conversion into biogas.

Assessing the anaerobic degradability and the potential recovery of biomethane from different biodegradable bioplastics in a full-scale approach.

The aim of the present study was to evaluate the anaerobic degradability and the potential recovery of biomethane from different bioplastics using a full-scale approach. Bioplastics were placed inside a real anaerobic digestion plant working under thermophilic conditions and quantitative and qualitative degradation of bioplastics was evaluated. Laboratory-scale experiments were used to determine the amount of biomethane produced by anaerobic degradation of bioplastics. Polylactic acid-based items may degrade completely using retention times compatible with anaerobic digestion plants contributing positively to biomethane production, i.e., in 90 days 397 ± 8 NL CH4 kgvolatile solids-1 were produced by polylactic acid-based cutlery. Starch-based shoppers showed a quick degradation of the starch component in the first month of anaerobic digestion, followed by a slow degradation of the polyester component. Anaerobic digestion and/or anaerobic digestion coupled to digestate composting may represent the best strategy to dispose these wastes meeting the principles of Circular Economy.

Polyphenol bioactivity evolution during the spontaneous fermentation of vegetal by-products.

Food industry by-products such as grape pomace (GP), tomato pomace (TP), and spent coffee grounds (SCG) are rich in polyphenols (PP) but are easily biodegradable. The aim of this study is to test Spontaneous Fermentation (SF) as treatment to modify PP profile and bioactivity. The results highlighted that the by-products' organic matter and the microbial populations drove the SF evolution; heterolactic, alcoholic, and their mixtures were the predominant metabolisms of TP, GP, and SCG + GP co-fermentation. Increases in the extractable amounts and antiradical activity occurred for all the biomasses. Regarding the aglycate-PPs (APP), i.e. the most bioreactive PPs, significant changes occurred for TP and GP but did not influence the anti-inflammatory bioactivity. The co-fermentation increased significantly chlorogenic acid and consumed most of the APPs, acting as a purification system to obtain a highly concentrated APP fraction, so that the extract might be employed for a specific purpose.

Degradation of bioplastics in organic waste by mesophilic anaerobic digestion, composting and soil incubation.

The aim of the study was to assess the effects of high concentrations (10 % w/w, data projected for 2030) of commercial bioplastics, i.e. starch based shopping bags (SBSB) and polylactic acid (PLA) tableware, in the organic fraction of municipal solid wastes (MSW) on compost quality obtained by pilot-scale dry mesophilic anaerobic digestion and subsequent composting of the digestate. After the biological processes, 48.1 % total solids (TS) of SBSB and 15 % TS of PLA degraded, resulting in a high bioplastics content (about 18 % TS) in compost. Subsequent compost incubation in soils indicated that bioplastics degraded by pseudo-zero order kinetics (0.014 and 0.010 mg C cm-2 d-1 for SBSB and PLA, respectively), i.e. complete degradation was expected in 1.6 years (SBSB) and 7.2 years (PLA), confirming the intrinsic biodegradability of bioplastics. Nevertheless, enhancing the rate and amount of bioplastics degradation during waste management represents a goal to decrease the amount of bioplastics reaching the environment.

The role of waste management in reducing bioplastics' leakage into the environment: A review.

Bioplastics are becoming more and more widespread as substitutes for petroleum-derived plastics due to their biodegradability. Bioplastics degradation under different environments has been described and reported to depend mainly on bioplastics' compositions and the environmental conditions. Incomplete degradation during waste management processes and leakage of bioplastics into the environment are becoming major concerns that need to be further investigated. In this context, the present paper aimed to review recent literature dealing with biodegradation of bioplastics under industrial (e.g. anaerobic digestion and composting) and natural (e.g. soil and water) environments, and to link it to the potential bioplastics' leakage into the environment. Reviewed data were used to estimate the potential role of waste management processes in decreasing the potential leakage of bioplastics. Depending on bioplastics' type and processing conditions, waste management can effectively reduce bioplastics' potential leakage, decreasing the concentration of these materials that can reach the natural environments.

Sisymbrium Officinale (the Singers' Plant) as an Ingredient: Analysis of Somatosensory Active Volatile Isothiocyanates in Model Food and Drinks.

Sisymbrium officinale (L.) Scop. (hedge mustard) is a wild common plant of the Brassicaceae family. It is known as "the singers' plant" for its traditional use in treating aphonia and vocal disability. The plant is rich in glucosinolates and isothiocyanates; the latter has been demonstrated to be a strong agonist in vitro of the Transient Receptor Potential Ankirine 1 (TRPA1) channel, which is involved in the somatosensory perception of pungency as well as in the nociception pathway of inflammatory pain. Volatile ITCs are released by the enzymatic or chemical hydrolysis of GLSs (glucosinolates) during sample crushing and/or by the mastication of fresh plant tissues when the plant is used as an ingredient. Some functional food and drink model preparations have been realised: honey enriched with seeds and flowers, infusions, cold drink (voice drink), artisanal beer, and a fermented tea (kombucha). Using SPME-GCMS chromatography, we analysed samples of the plant and of the food preparations adopting conditions that simulate the release of isothiocyanates (ITCs) during oral assumption. Two active compounds, iso-propylisothiocyanate and 2-butylisothiocyanate, have been assayed. The concentration of ITCs varies according to temperature, pH, grinding conditions, and different plant organs used. Kombucha-type fermentation seems to eliminate the ITCs, whereas they are retained in beer. The ITCs' concentration is higher when entire seeds and flowers are used.

Antioxidant and Anti-Inflammatory Activities of the Crude Extracts of Raw and Fermented Tomato Pomace and Their Correlations with Aglycate-Polyphenols.

Two tomato pomace (TP) were studied as feedstocks to obtain extracts that are rich in polyphenols. TPs prompt degradation impairs biomass safety, thus naturally present microflora were tested to perform conservation, and own lactic bacteria became predominant after 60 days of treatment. The extracts of TPs and TPs fermented (TPF) were chemically characterized and tested for antioxidant and anti-inflammatory activities. Flavonoids and phenolic acids were classed as aglycone-polyphenols (A-PP), the most bioactive polyphenol fraction. Fermentation led to a reduction of the A-PP amount, but no significant change in composition. Antioxidant power increased, despite the A-PP reduction, for the presence of fermentation metabolites having aromatic-substituent. TP and TPF both have anti-inflammatory properties that were strictly dependent upon the A-PP content. Fermentation preserved the anti-inflammatory activity and the Partial Least Square (PLS) identified as the most active molecules naringenin chalcone, kaempferol, gallic acid, and cinnamic acid, together with the definition of the active dose.

Isothiocyanates and Glucosinolates from Sisymbrium officinale (L.) Scop. ("the Singers' Plant"): Isolation and in Vitro Assays on the Somatosensory and Pain Receptor TRPA1 Channel.

Sisymbrium officinale (L.) Scop. is a wild common plant of the Brassicaceae family. It is known as "the singers' plant" for its traditional use in treating aphonia and vocal disability. Despite its wide use in herbal preparations, the molecular mechanism of action of S. officinale extracts is not known. The plant is rich in glucosinolates and isothiocyanates, which are supposed to be its active compounds. Some members of this family, in particular allylisothiocyanate, are strong agonists of the transient receptor potential ankyrin 1 (TRPA1) channel, which is involved in the somatosensory perception of pungency as well as in the nociception pathway of inflammatory pain. This study aims to isolate the glucosinolates and isothiocianates from fresh S. officinale to identify the major components and test their activity in in vitro assays with a cloned TRPA1 channel. Samples of cultivated S. officinale have been extracted and the active compounds isolated by column chromatography, HPLC and PTLC. The main components glucoputranjivin, isopropylisothiocyanate and 2-buthylisothiocianate have been tested on TRPA1. The glucosinolates glucoputranjivin and sinigrin turned out to be inactive, while isopropylisothiocyanate and 2-buthylisothiocyanate are potent agonists of TRPA1, with an EC50 in the range of the high potency natural agonists identified so far for this somatosensory channel.

Assessment of Tryptophan, Tryptophan Ethylester, and Melatonin Derivatives in Red Wine by SPE-HPLC-FL and SPE-HPLC-MS Methods.

Melatonin (MEL) is an indoleamine produced mainly by the pineal gland in vertebrates. It plays a significant role in the regulation of circadian rhythms, mitigation of sleeping disorders, and jet lag. This compound is synthetized from tryptophan (TRP) and it has been found in seeds, fruits, and fermented beverages, including wine. Wine is also a source of other tryptophan derivatives, the tryptophan ethylester (TEE) and MEL isomers (MISs), for which the biological properties need to be elucidated. An analytical method for the simultaneous quantification of TRP, TEE, and MEL was developed by a Solid Phase Extraction (SPE) of a preconcentration of wine followed by high performance liquid chromatography (HPLC) analysis either with fluorescence or mass spectrometer detectors. The analytical method showed a relative standard deviation (RSD) lower than 8%, except for TRP (RSD 10.5% in wine). The recovery was higher than 76%. The versatility of SPE preconcentrations allowed for the adequate preconcentration of wine sample as well as detection of low concentrations, an important aspect especially for MEL (detection limit 0.0023 µg/L). The proposed method proved to be suitable for assessing the investigated compounds in some red wine samples, where 74.4⁻256.2 µg/L and 0.038⁻0.063 µg/L of TEE and MEL were detected, respectively. Five MISs were also found in wine samples in concentrations up to 1.97 µg/L.

Low iron availability and phenolic metabolism in a wild plant species (Parietaria judaica L.).

Plant phenolics encompass a wide range of aromatic compounds and functions mainly related to abiotic and biotic environmental responses. In calcareous soils, the presence of bicarbonate and a high pH cause a decrease in iron (Fe) bioavailability leading to crop yield losses both qualitatively and quantitatively. High increases in phenolics were reported in roots and root exudates as a consequence of decreased Fe bioavailability suggesting their role in chelation and reduction of inorganic Fe(III) contributing to the mobilization of Fe oxides in soil and plant apoplast. Shikimate pathway represents the main pathway to provide aromatic precursors for the synthesis of phenylpropanoids and constitutes a link between primary and secondary metabolism. Thus the increased level of phenolics suggests a metabolic shift of carbon skeletons from primary to secondary metabolism. Parietaria judaica, a spontaneous plant well adapted to calcareous environments, demonstrates a high metabolic flexibility in response to Fe starvation. Plants grown under low Fe availability conditions showed a strong accumulation of phenolics in roots as well as an improved secretion of root exudates. P. judaica exhibits enhanced enzymatic activities of the shikimate pathway. Furthermore, the non-oxidative pentose phosphate pathway, through the transketolase activity supplies erythrose-4-phosphate, is strongly activated. These data may indicate a metabolic rearrangement modifying the allocation of carbon skeletons between primary and secondary metabolism and the activation of a nonoxidative way to overcome a mitochondrial impairment. We suggest that high content of phenolics in P. judaica play a crucial role in its adaptive strategy to cope with low Fe availability.

Application of the split root technique to study iron uptake in cucumber plants.

The regulation exerted by the Fe status in the plant on Fe deficiency responses was investigated in Cucumis sativus L. roots at both biochemical and molecular levels. Besides the two activities strictly correlated with Fe deficiency response, those of the Fe(III)-chelate reductase and the high affinity Fe transporter, we considered also H(+)-ATPase (EC 3.6.3.6) and phosphoenolpyruvate carboxylase (EC 4.1.1.31), that have been shown to be involved in this response. Both enzymatic activities and gene expression were monitored using a split root system. Absence of Fe induced the expression of the four transcripts, accompanied by an increase in the corresponding enzymatic activities. The application of the split root technique gave some information about the regulation of Fe uptake. In fact, 24 h after split root application, transcripts were still high and comparable to those of the -Fe control in the Fe-supplied half side, while in the -Fe side there was a drop in the expression and the relative enzymatic activities. Major changes occurred after 48 and 72 h. The coordinated regulation of these responses is discussed.

Adaptive strategies of Parietaria diffusa (M.&K.) to calcareous habitat with limited iron availability.

The study of native plants growing in hostile environments is useful to understand how these species respond to stress conditions. Parietaria diffusa (M.&K.) is able to survive in highly calcareous soils and extreme environments, such as house walls, without displaying any chlorotic symptoms. Here, we have investigated the existence of Strategy I complementary/alternative mechanism(s) involved in Fe solubilization and uptake and responsible for Parietaria's extraordinary efficiency. After assessing the specific traits involved in a calcicole-behaviour in the field, we have grown plants in conditions of Fe deficiency, either direct (-Fe) or induced by the presence of bicarbonate (+FeBic). Then, the growth performance, physiological and biochemical responses of the plants were investigated. The study shows that in Parietaria+FeBic, the classical responses of Strategy I plants are activated to a lower extent than in -Fe. In addition, there is a greater production of phenolics and organic acids that are both exuded and accumulated in the roots, which in turn show structures similar to 'proteoid-like roots'. We suggest that in the presence of this constraint, Parietaria undergoes some metabolic rearrangements that involve PEP-consuming reactions and an enhancement of the shikimate pathway.

Iron deficiency differently affects metabolic responses in soybean roots.

Iron deficiency responses were investigated in roots of soybean, a Strategy I plant species. Soybean responds to iron deficiency by decreasing growth, both at the root and shoot level. Chlorotic symptoms in younger leaves were evident after a few days of iron deficiency, with chlorophyll content being dramatically decreased. Moreover, several important differences were found as compared with other species belonging to the same Strategy I. The main differences are (i) a lower capacity to acidify the hydroponic culture medium, that was also reflected by a lower H(+)-ATPase activity as determined in a plasma membrane-enriched fraction isolated from the roots; (ii) a drastically reduced activity of the phosphoenolpyruvate carboxylase enzyme; (iii) a decrease in both cytosolic and vacuolar pHs; (iv) an increase in the vacuolar phosphate concentration, and (v) an increased exudation of organic carbon, particularly citrate, phenolics, and amino acids. Apparently, in soybean roots, some of the responses to iron deficiency, such as the acidification of the rhizosphere and other related processes, do not occur or occur only at a lower degree. These results suggest that the biochemical mechanisms induced by this nutritional disorder are differently regulated in this plant. A possible role of inorganic phosphate in the balance of intracellular pHs is also discussed.

Adaptive responses to iron-deficiency in callus cultures of two cultivars of Vitis spp.

The correlation between iron chlorosis resistance and induction of adaptive mechanisms in grapevine calli belonging to cultivars with different susceptibility to iron chlorosis has been investigated. Fe(III)-chelate reductase was clearly linked to the Fe-efficiency status of the genotype. When growing on iron deprived medium (-Fe) calli of the Fe-efficient genotype "Cabernet sauvignon" showed a remarkable increase in enzyme activity, up to five times higher, with respect to +Fe cultures. Moreover, 31P-NMR revealed that in -Fe medium the increase of vacuolar Pi content of the Fe-efficient cultures was more pronounced than that recorded for the Fe-inefficient Vitis riparia. Furthermore, Fe starvation also enhanced the production of phenolic compounds in calli of "Cabernet sauvignon" with respect to those of Vitis riparia. The role of H(+)-ATPase as a marker of Fe-efficiency in tissue culture remains ambiguous in the case of grapevines.