Search Results (482)

In the valorization of organic waste within circular bioeconomy frameworks, compost and insect frass are increasingly used as soil amendments, yet their molecular composition and the metabolic signatures of biological processing remain poorly characterized. In this study, high-resolution magic angle spinning (HRMAS) nuclear magnetic resonance (NMR) was applied to intact compost and frass samples to explore their metabolic profiles and assess the potential of this technique to detect bioindicators of vermi- and insect-associated biotransformation without destructive sample preparation. HRMAS NMR experiments included water-suppressed one-dimensional ¹H spectra and selected two-dimensional experiments (¹H–¹³C HSQC and ¹H–¹³C HMBC) to support signal assignment. The analysis revealed clear differences between compost with and without vermicomposting activity, with low-molecular-weight resonances assigned to glycine betaine (betaine), a characteristic metabolite associated with biotransformation. In Tenebrio molitor frass, ¹H-HRMAS spectra displayed a distinct set of small-molecule signals, including betaine resonances detected for the first time in this matrix. Time-resolved monitoring showed that betaine signals remained stable during the studied period. These findings demonstrate that HRMAS NMR provides a minimally invasive, versatile platform for direct characterization of compost and frass, supporting the identification of metabolic signatures linked to vermi- and insect-mediated processing. Full article

Winery residues generated by the wine industry represent an important sustainability challenge but also a valuable resource for producing vermicompost-derived products with potential agricultural applications through vermicomposting. This study evaluated the effects of aqueous vermicompost extracts produced from winery residues on the early in vitro development and physiological performance of garden cress (Lepidium sativum L.) and cucumber (Cucumis sativus L.) seedlings. Seedlings were cultivated on peat-based pellets (Jiffy-7^®) under controlled conditions and treated with two extract concentrations (10% and 20%, w/v) or distilled water (control). After 30 days, morphological traits (shoot height, leaf number and biomass) and biochemical parameters (photosynthetic pigments and total phenolics) were assessed. Both species showed high survival rates (>85%) and no phytotoxic symptoms. Compared with the control, VE20% increased chlorophyll a, chlorophyll b, and total chlorophyll contents in garden cress by 40.3%, 35.9%, and 38.9%, respectively, whereas VE10% increased chlorophyll a, total chlorophyll, and carotenoid contents in cucumber by 15.7%, 11.5%, and 25.0%, respectively. Total phenolic content did not differ significantly among treatments in either species (p > 0.05). These findings indicate that vermicompost extracts produced from winery residues exhibited low phytotoxic potential under the experimental conditions tested and influenced photosynthetic pigment accumulation without adversely affecting seedling growth. These responses warrant further investigation under ex vitro and field conditions to determine whether the observed physiological changes translate into relevant agronomic effects. Full article

The accumulation of agricultural waste poses significant agronomic and environmental challenges in tropical smallholder farming systems where organic wastes remain underutilized. This study evaluated the effectiveness of vermicomposting with Eisenia fetida in enhancing nutrient recovery and improving the quality of organic fertilizers produced from agricultural waste. Four substrate treatments—poultry manure and vegetable waste (T1), cow dung, chicken manure, and vegetable waste (T2), cow dung and vegetable waste (T3), and a control without earthworms (T4)—were assessed over a period of 60 days. Key physicochemical properties evaluated included bulk density, pH, electrical conductivity, organic carbon, total nitrogen, available phosphorus and potassium, and the C:N ratio. Vermicomposting significantly improved nutrient composition, with the C:N ratio decreasing from 26.43 in the control treatment to 12.23, indicating enhanced compost maturity. Treatment T2 recorded the highest concentrations of total nitrogen (2.63%), phosphorus (1.21%), and potassium (1.45%). A significant reduction in organic carbon also indicated enhanced mineralization during the decomposition process. Compared with traditional composting, vermicomposting improved nutrient availability, compost maturity, and overall compost quality. These findings demonstrate that vermicomposting is an effective resource recovery strategy for converting agricultural waste into nutrient-rich organic fertilizer while supporting sustainable and climate-resilient agricultural systems. Full article

The accumulation of agricultural residues represents a major environmental challenge in developing countries, particularly in tropical regions where inadequate waste management contributes to environmental degradation. Vermicomposting has emerged as a sustainable technology capable of transforming organic waste into nutrient-rich fertilizers through the combined activity of earthworms and microorganisms. This study evaluated the influence of different agricultural residues on the physicochemical properties of vermicompost under tropical conditions in Mozambique. The experiment was conducted at the experimental field of the Catholic University of Mozambique—Faculty of Engineering in Chimoio district, using three substrate types: leguminous residues (T1), cereal residues (T2), and horticulture residues (T3). Each treatment was combined with poultry manure in a 1:1 ratio. Vermicomposting was carried out using Eisenia fetida. Because treatments were not independently replicated, results are presented as descriptive physicochemical characterizations (means ± SD of analytical subsamples). All treatments produced vermicompost with physicochemical characteristics consistent with established maturity criteria: pH 8.03–9.07, moisture 50–76%, and electrical conductivity 527–939 µS/cm, C/N ratio ranged from 15.56 to 20.19, total nitrogen ranged from 1.2 to 1.8%, phosphorus from 0.6 to 0.9%, and potassium from 1.1 to 1.5%. T1 (leguminous residues + poultry manure) showed the highest nutrient concentrations and lowest C/N ratio. These descriptive findings suggest that vermicomposting represents a promising strategy for recycling agricultural residues into vermicompost with characteristics consistent with established maturity criteria, highlighting the importance of substrate selection. The findings suggest that vermicomposting is a promising strategy for sustainable waste management and soil fertility improvement in tropical smallholder systems. Full article

A sustainable method of improving soil fertility and developing climate-resilient cropping systems is vermicomposting agricultural waste. This study hypothesized that vermicompost derived from mixed organic agricultural wastes would significantly improve soil fertility, crop productivity, and drought resilience compared to single-substrate treatments and the unamended control. The effects of vermicompost generated from mixed organic wastes using Eisenia fetida on soil quality, crop performance, and drought resilience of lettuce (Lactuca sativa, Eden variety) were evaluated in this study using a randomized complete block design. Crop performance indicators included germination, growth characteristics, biomass, SPAD chlorophyll content, and yield, while soil physicochemical properties, including pH, organic carbon, total nitrogen, available phosphorus, exchangeable potassium, electrical conductivity (EC), and cation exchange capacity (CEC), were assessed both before and after amendment application. The effects of drought stress were evaluated using leaf surface temperature, wilting score, recovery time, and survival rate. The results demonstrated that vermicompost application significantly improved soil fertility and crop performance relative to the control treatment (p < 0.05). The best-performing treatment (T2) increased soil organic carbon by approximately 22–28%, total nitrogen by 18–24%, available phosphorus by 20–27%, and exchangeable potassium by 16–21% compared with the control. Fresh biomass increased by approximately 14–17%, marketable yield improved by 16–24%, and SPAD chlorophyll values increased by nearly 20%, indicating enhanced photosynthetic efficiency and nutrient uptake. T2 showed the most resilience under drought stress, with ~94.9% survival rate, reduced wilting severity, shortened recovery time and sustained stable leaf temperature (~27.8 °C), whereas low-performing treatments and the control recorded survival rates of only ~70–78%. Mixed organic waste substrates consistently outperformed single-substrate treatments, demonstrating synergistic effects on nutrient cycling, microbial activity, soil structural quality, and drought tolerance. These findings provide quantitative evidence that vermicomposting can simultaneously enhance soil fertility, crop productivity, and drought resilience, highlighting its strong potential as a scalable climate-smart strategy for sustainable agriculture, circular bioeconomy development, and organic waste valorization in smallholder farming systems. Full article

Replacing peat in green roof substrates with sustainable alternatives while maintaining plant performance and ecosystem services remains a critical challenge. We studied biochar-substrate interactions across four commercial green roof formulations (based on the type of organic component) in a greenhouse experiment: pure vermicompost, vermicompost + fen peat, fen peat, and mixed fen/high-moor peat. Substrates were amended with straw biochar, pine bark biochar, or left unamended (5% v/v, n = 4 replicates) and planted with a grass seed mixture mimicking early green roof establishment. Plant growth, nutrient contents (nitrate and phosphate contents), and microbial indicators (microbial biomass carbon (MBC), qCO₂, and enzyme activities) were measured 30 days after the experiment began. Straw biochar in vermicompost boosted nitrate (90.8 mg kg⁻¹) and root N (3.1%) compared to the control, while pine bark biochar in mixed peat released phosphate (+375%) and maximized MBC (874 µg g⁻¹). Biochar intensified substrate effects, suppressing CO₂ in peat through liming effects (pH from 4.6 to 6.5–7.1) but priming respiration in vermicompost via labile C supply. PCA explained 63% of the variance, with nitrate, plant N, and microbial parameters driving substrate separation. These short-term greenhouse results demonstrate critical biochar-substrate specificity for green roof substrate development, emphasizing formulation-specific matching over universal biochar application. Full article

Municipal organic waste management remains a major challenge for sustainable urban development, particularly in regions requiring decentralized treatment alternatives that reduce landfill dependency and promote circular resource recovery. This study compared Takakura composting and vermicomposting for the stabilization of municipal organic waste under decentralized operational conditions in the Ecuadorian Amazon and developed a Composite Circular Resource Recovery and Process Performance Index (CRRPPI) to evaluate resource recovery efficiency. Municipal organic waste was treated through Takakura composting, vermicomposting, and uncontrolled decomposition (control). Operational performance was assessed using material conversion efficiency, process productivity, nutrient recovery efficiency, nutrient productivity, and final physicochemical characteristics. These indicators were integrated into the CRRPPI framework to provide a multidimensional assessment of circular resource recovery performance. Takakura composting showed the highest operational efficiency, achieving material conversion efficiencies of up to 0.80, process productivity values of 1.23 kg day⁻¹, and superior nutrient recovery efficiencies for nitrogen (0.835), phosphorus (0.730), and potassium (0.880). The highest CRRPPI values were obtained for Takakura treatments (0.835–0.842), while vermicomposting showed intermediate performance, and the control treatment presented the lowest resource recovery efficiency (0.216). Sensitivity analysis confirmed ranking stability under ±20% weighting variations, and ANOVA followed by Tukey’s HSD test identified significant differences among treatments (p < 0.05). The results indicate that Takakura composting is an effective strategy for decentralized municipal organic waste valorization and nutrient recirculation. Furthermore, the proposed CRRPPI provides a practical exploratory framework for integrated evaluation of biological stabilization technologies by simultaneously considering operational performance and circular resource recovery. Full article

Vermicomposting is an eco-friendly biotechnology for organic waste valorization. As the primary product of earthworm biotransformation, vermicompost is a high-value bio-organic fertilizer abundant in diverse biologically active components. To date, most studies have focused on quality variation during the earthworm transformation process, while research on quality variations in the resulting vermicompost fertilizer during long-term storage remains scarce. To explore the shelf-life of vermicompost fertilizer and its key influencing indicators, this study investigated the changes in quality indicators in sealed-packaged vermicompost over a 180-day period using two typical vermicompost, namely cattle manure vermicompost (CM) and straw-amended cattle manure vermicompost (CMS). The temporal dynamics of physicochemical properties, nutrient contents, humification indices, enzyme activities, and microbial communities were monitored. The vermicompost quality was evaluated, and core quality drivers were identified using an integrated principal component analysis-partial least squares (PCA-PLS) approach. The results indicated that moisture content (MC), total organic carbon (TOC), and total nitrogen (TN) declined progressively, whereas available phosphorus (AP) and available potassium (AK) peaked at day 150 and day 120, respectively, and the humification rate (HR) increased by 2.6–4.0-fold. Bacterial diversity and relative abundance slightly decreased, accompanied by taxonomic differentiation, whereas fungal communities maintained stable diversity. Most enzyme activities, including urease, phosphatase, catalase, and dehydrogenase, reached their maxima at day 120. Comprehensive quality scores peaked at day 150, with a marked decline observed by day 180. The recommended shelf-life of vermicompost fertilizer is 150 days. The key quality determinants include TN, electrical conductivity (EC), pH, actinomycete abundance, TOC, TP, bacterial abundance, AP, AK, and HR. These findings provide theoretical support and references for the storage management and quality control of commercial vermicompost products in practice. Full article

Applying sludge from wastewater treatment plants to agricultural soils is a major pathway for microplastics (MPs) to reach terrestrial ecosystems, with critical implications for food and environmental safety. A longitudinal analysis (13 months) was conducted to evaluate vermicomposting (with Eisenia andrei) as a remediation strategy, comparing fresh sludge, worm casts, mature vermicompost, and control (earthworm-free) compost. MPs were isolated by chemical digestion and density separation and characterized by optical microscopy and μ-Raman spectroscopy. The MP content of fresh casts (584 ± 45 MP·g⁻¹; p = 0.036), driven by the mechanical and digestive activity of earthworms, showed a significant increase relative to sludge, in contrast to the invariant results observed in the control compost. The MP content of the vermicompost initially increased to 755 ± 88 MP·g⁻¹ after 3 months of maturation due to gradual fragmentation by microbial degradation. However, after 13 months, the MP content in vermicompost, compared to the initial sludge, decreased by 62% (reduction of 625 ± 49 MP·g⁻¹; p < 0.001), more than the 56% (reduction of 560 ± 83 MP·g⁻¹; p = 0.001) observed in the control compost, suggesting a net long-term decrease. Morphological, colorimetric, and compositional changes, reflected by browning and reduced particle size and natural fiber content, revealed a temporal lag, with earlier transformation in vermicomposted samples. Overall, the findings show the potential of vermicomposting to reduce the MP content of sewage sludge used as a soil amendment. Full article

Soilless horticultural media offer a solution to limited arable land but are often nutrient-inert, requiring efficient nutrient management strategies. This study aimed to evaluate the potential of seaweed biochar-amended vermicompost (VC) as a nutrient-supplying growing medium for tomato (Solanum lycopersicum L.) seedling establishment and vegetative growth. Coco peat was progressively replaced with VC (0–100%, w/w) under fertilized and unfertilized conditions during seedling development, and selected treatments were further evaluated during vegetative growth. Growth parameters, including emergence, plant height, leaf area, stem diameter, biomass, and chlorophyll content, were measured. Treatments significantly affected (p < 0.05) all parameters. The highest VC level (100%) reduced seedling emergence by 10.42% compared to the control but significantly improved seedling height (13.69 cm) and leaf area (49.45 cm² plant⁻¹) under fertilized conditions. During vegetative growth, the control (0% VC) produced the highest biomass (9.55 g) and plant height (67.43 cm), while higher VC rates (75–100%) enhanced chlorophyll content and maintained acceptable plant growth. Overall, VC showed potential as a sustainable growing medium component for tomato production, although plant responses varied according to growth stage and incorporation rate. Reduced emergence at higher VC levels indicates that further research is needed to optimize substrate management strategies for seedling establishment. Full article

The valorization of agro-industrial residues and sewage sludge into value-added products through vermicomposting represents a promising strategy for nutrient recycling and waste reduction. This study evaluated the effects of aqueous extracts obtained from five vermicomposts (VC1-VC5) produced from different mixtures of vineyard and winery residues and sewage sludge on cucumber (Cucumis sativus L.) seedlings grown under in vitro conditions. The aqueous extracts (10%, w/v) were characterized in terms of pH, electrical conductivity, and total polyphenolic content, and applied to cucumber seedlings cultivated for 30 days under sterile and controlled in vitro conditions using commercially available peat pellets (Jiffy-7^®). Seedling development was monitored throughout the experiment, and morphological and biochemical parameters were assessed at the end of the 30-day assay. All extracts supported seedling development, with no evidence of phytotoxicity. The application of VC2 and VC4 extracts resulted in significant increases in fresh and dry weight, while VC2 led to higher chlorophyll and carotenoid contents. Conversely, VC3 and VC5 extracts were associated with slight reductions in growth parameters and photosynthetic pigment content. Correlation analysis suggested positive associations between biomass accumulation and chlorophyll content, and negative association between total polyphenolic content and stem growth. Overall, the results indicate that aqueous vermicompost extracts were not phytotoxic under the tested conditions, although their effects appear to depend on extract composition, highlighting the importance of feedstock selection for sustainable horticultural applications. Full article

Soil degradation and organic matter depletion threaten the sustainability of Mediterranean agroecosystems, highlighting the need for effective and sustainable soil restoration strategies. This study evaluated the short-term effects of composts and vermicomposts derived from chestnut sawdust and food waste on soil functionality and broccoli quality under field conditions using a multi-indicator assessment framework. Six fertilization treatments, including composts, vermicomposts, horse manure, mineral NPK fertilization, and an unfertilized control, were tested in broccoli-cultivated plots. Organic amendments significantly improved soil chemical, biochemical, and biological properties compared with mineral fertilization and the unfertilized control. Vermicompost 10/90 (10% sawdust:90% wet waste) produced the strongest effects, increasing soil organic carbon and organic matter by about 85%, cation exchange capacity by 45%, and dehydrogenase activity by 83% compared with the unfertilized control. Compost and vermicompost treatments also enhanced microbial biomass carbon, enzymatic activities, and QBS-ar values, indicating improved soil biological quality and microarthropod diversity. Broccoli quality was significantly influenced by fertilization regime. Vermicompost 10/90 increased vitamin C by 154%, vitamin E by 54%, total proteins by 18%, and total carbohydrates by 17% compared with the unfertilized control. Organic amendments also enhanced total phenolics, flavonoids, and antioxidant activity relative to NPK and control treatments. Principal component and correlation analyses revealed strong positive relationships among organic matter accumulation, microbial activity, enzymatic processes, soil biodiversity, and crop nutritional quality. Overall, the integrated multi-indicator approach demonstrated that waste-derived organic amendments improve soil functionality and crop quality simultaneously, supporting their use as sustainable tools for circular and resilient Mediterranean agricultural systems. Full article

The increasing production of sewage sludge (SS) from wastewater treatment plants presents significant environmental challenges worldwide, requiring sustainable treatment strategies that enable resource recovery while minimizing environmental risks. Although composting is widely recognized as an effective method for SS stabilization, current technologies still exhibit limitations, including inefficient oxygen transfer, uneven aeration, high greenhouse gas emissions, and insufficient control of emerging contaminants. This review aims to synthesize current knowledge on SS composting with a focus on strategies for improving operation performance and reducing environmental impacts. Recent studies indicate that composting performance is strongly influenced by factors such as temperature, moisture content, aeration, carbon-to-nitrogen (C:N) ratio, and the use of suitable bulking agents. In addition to conventional approaches, alternative technologies—including co-composting, in-vessel systems, vermicomposting, and pretreatment methods—are discussed as pathways for improving system efficiency. Special attention is given to emerging innovations such as nanobubble aeration, which shows potential to enhance oxygen transfer and reduce anaerobic zones, although its application in composting remains insufficiently explored. The review highlights critical knowledge gaps related to aeration optimization, contaminant behaviour, and process integration, identifying opportunities where further scientific research can significantly advance SS composting toward more efficient and environmentally sustainable systems. Full article

Background: Estrogen deficiency negatively affects alveolar bone by disrupting key regulators of bone remodeling. Humic acids (HAs) are natural compounds with recognized antioxidant and anti-inflammatory properties that may attenuate bone resorption. This study investigated the effects of HAs on alveolar bone in an experimental model of estrogen depletion. Methods: Female C57BL/6 mice were randomly assigned to four groups: Sham, Sham + HA, ovariectomized (OVX), and OVX + HA. Estrogen deficiency was induced by bilateral ovariectomy. HAs derived from vermicomposted biomass were administered daily by oral gavage (80 mg/kg) for 28 days. At the end of the experimental period, mandibles were collected for structural, mineral, and histological analyses. Bone elemental composition was assessed using scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM/EDS). Alveolar bone loss was evaluated by histomorphometry, while RANKL and osteoprotegerin (OPG) expression were assessed by immunohistochemistry. Osteoclasts were quantified by tartrate-resistant acid phosphatase (TRAP) staining. Data were analyzed using two-way ANOVA followed by Bonferroni’s post hoc test. Results: Ovariectomy resulted in reduced calcium and phosphorus content, increased alveolar bone loss, elevated RANKL immunolabeling, increased osteoclast numbers, and a higher RANKL/OPG ratio (p < 0.05). HA treatment increased calcium and phosphorus content and attenuated alveolar bone loss in OVX animals (p < 0.05). Additionally, HA treatment partially increased OPG expression and reduced the RANKL/OPG ratio (p < 0.05), without significantly affecting RANKL immunolabeling or osteoclast numbers. Conclusions: HA therapy attenuated alveolar bone resorption in a model of estrogen depletion, possibly associated with modulation of the RANKL/OPG balance. Full article

Sustainable phosphorus (P) management in agriculture requires a circular economy approach through the use of so-called bio-based fertilizers (BBFs). The properties of BBFs vary widely depending on raw materials and production processes. However, it is still unknown how these properties, and particularly the dominant P compounds determine not only the efficiency of BBFs in supplying P to crops, but also their effects on soil functioning and crop quality. This study aimed to evaluate the efficiency of a representative set of BBFs, and relate this efficiency to their composition and dominant P compounds. To this end, 14 BBFs were studied: four from water purification (struvite, vivianite, and sewage sludge with and without composting), four composts (municipal solid waste (MSW), vineyard residues, and two using olive husks), three vermicomposts (two homemade and one commercial), fish meal, digestate, and a commercial organic fertilizer. Phosphorus forms in BBFs were determined using ³¹P nuclear magnetic resonance spectroscopy (P-NMR). The BBFs were compared to a single superphosphate (SSP) in a pot experiment growing wheat in two different alkaline soils, one rich in iron (Fe) oxides and one rich in carbonates. The effects on critical elements in grain [magnesium, Fe, zinc (Zn), manganese, and copper] and enzyme activities related to soil functioning and P cycling were also assessed. The dominant P compound in the BBFs was orthophosphate (73.8–89.5% of the total P in the NaOH–EDTA extracts). The MSW had the highest polyphosphate content (4.1%), a complex inorganic P compound. The organic P content ranged from 9.2% (fish meal) to 25.5% (Moge). Sewage sludge and composted sludge contributed high levels of phosphonates (4.1 and 5.6% of extracted P). The most abundant organic P compound class was inositol hexakisphosphates (IHPs), and myo-IHP (phytate) was the dominant IHP stereoisomer (1.2–6.4%) followed by D-chiro-IHP and scyllo-IHP. Plant dry matter and grain yield with most BBFs were not significantly different from that of SSP in both soils, likely due to the high concentrations of phosphate in relatively soluble forms in most of the BBFs. Vivianite and sewage sludge resulted in significantly higher grain yield than SSP (43% and 40%, respectively) in the carbonate-rich soil, likely due to progressive phosphate dissolution, which decreased the precipitation rate of insoluble calcium (Ca) phosphates. The highest P recoveries were obtained with horse manure vermicompost (65% and 15% higher than SSP in the Fe oxide-rich and in the carbonate-rich soil, respectively), partially attributed to the decreased precipitation rate of insoluble Ca phosphates with the added organic matter. Some BBFs increased micronutrient concentrations in grains and most decreased the P-to-Zn ratio relative to SSP. Overall, phosphatase and β-glucosidase activities increased with carbon-rich BBFs. Most of the studied BBFs could effectively replace fertilizers from non-renewable sources, in some cases with better crop P recoveries. Furthermore, some BBFs could provide additional benefits to grain quality, in terms of micronutrient supply for humans, and soil functioning. Full article