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Open access Jul 2026

Exploratory Assessment of Some Regional Food Wastes as Potential Biofertilizers: Effects on Vegetative Growth and Phytochemical Profile of Phaseolus vulgaris L.

Developing innovative green strategies regarding the integration of by-products and waste from the food industry for sustainable agriculture and a circular economy represents a current challenge of great interest. The present exploratory study evaluated four regional potential food-waste-derived biofertilizers under controlled greenhouse conditions. Eggshell powder (EGP), whey, sea buckthorn pomace powder (SBPP), and grape pomace hydroalcoholic extract (GPHAE), used separately or in combination, were tested to observe the response of a relevant crop, Phaseolus vulgaris L. var. communis Auria Bacăului, in terms of vegetative growth parameters and its phytochemical profile. Plant biometric parameters, some representative metabolites (chlorophyll, carotenoids, polyphenolic compounds, and amino acids), and antioxidant activity were investigated using appropriate analytical techniques. The results demonstrated that bean plants grown on soil amended with EGP exhibit high biometric values, validating the efficacy of this by-product as a potential biofertilizer. The mixture of water and GPHAE used on the amended soils with EGP, and with EGP and SBPP, induces a positive effect on the total chlorophyll content accumulated in the bean samples (0.204–0.212 mg/g) compared to similar samples sprayed only with water. The mixture of water, whey, and GPHAE resulted in free amino acid accumulation in beans regardless of soil amendment. The highest synergetic effect on amino acid accumulation was found between this fertigation solution and the soil supplemented with EGP. The overall results of the present work confirm the potential of these regional food by-products and waste as biofertilizers, offering a dual solution for food industry waste management and sustainable agricultural development.

E. Bran, Luminița-Bianca Grosu, Gabriel-Alin Iosob et al. · 0 citations
Open access Aug 2026

Biostimulant Extracts from Tetradesmus obliquus Cultivated in Rice Parboiling Effluent Improve Rice Germination and Generate PUFA-rich Residues in a Circular Biorefinery Strategy

The valorization of agro-industrial effluents (AIEs) as cultivation media for microalgae represents a promising strategy for integrating wastewater remediation with bioproduct generation. The increasing demand for sustainable and climate-resilient agricultural systems, combined with the need to reduce microalgal production costs, has intensified interest in circular biorefinery approaches capable of converting industrial residues into bioactive compounds. In this context, Tetradesmus obliquus demonstrates strong potential for the production of agricultural biostimulants and nutritionally valuable metabolites. In this study, T. obliquus biomass cultivated in Bold’s basal medium (BBM) and rice parboiling AIE underwent biochemical characterization and aqueous extraction. Germination and seed vigor assays evaluated the biostimulant effects of the extracts on four rice cultivars ( Oryza sativa L.) under standard and cold-stress conditions, while the residual biomass underwent lipid profiling by gas chromatography–mass spectrometry. AIE-derived biomass showed higher total carbohydrate content (197.12 mg g⁻ 1 ) than BBM biomass (121.33 mg g⁻ 1 ), whereas BBM biomass presented higher chlorophyll levels (5.37 mg g⁻ 1 ). Amino acid profiles also differed between cultivation systems; BBM extracts contained higher proportions of glutamic acid, valine, and glycine, whereas AIE extracts showed enrichment in alanine, proline, and histidine, indicating metabolic adaptation to effluent-based cultivation. Despite these compositional differences, both extracts promoted comparable biostimulant effects, particularly at treatments 3L·100 kg⁻ 1 seed, achieving germination rates above 97% in IRGA 424 RI relative to the control. These findings demonstrate that T. obliquus cultivated in AIE preserves bioactive functionality and supports circular biorefinery strategies integrating wastewater remediation, agricultural biostimulant production, and lipid valorization for potential aquaculture applications.

Diego Serrasol do Amaral, D. T. Bueno, Paula Freitas Filoda et al. · 0 citations
Open access Jul 2026

Utilization of Sweet Potato Leaf Extract (Ipomoea batatas L.) as a Bioflocculant in Clean Water Treatment

The increasing demand for clean water due to population growth and human activities is not matched by its availability, as many regions still face pollution from domestic and industrial waste. This study explores the potential of sweet potato leaf extract (Ipomoea batatas L.) as a natural bioflocculant in water treatment. Sweet potato leaves contain secondary metabolites such as flavonoids, saponins, and tannins, which contribute to coagulation–flocculation processes. The extract was applied to contaminated water samples and evaluated for its effectiveness in reducing turbidity, suspended solids, and other water quality parameters. The results show that the extract significantly improved water quality at optimal concentrations, outperforming the control. Moreover, it is environmentally friendly as it does not produce hazardous residues. Therefore, sweet potato leaf extract has potential as an economical, sustainable, and safe alternative bioflocculant for clean water treatment.

Hotman Saragi Napitu, Muhammad Farhan, Giovani Mei et al. · 0 citations
Open access 2026

Effect of Methylobacterium on the yield and quality of cauliflower (Brassica oleracea)

Abstract The soil used is sandy in texture, low in nutrients, and low in organic matter, and therefore has low cation exchange capacity. Therefore, the objective was to evaluate the effectiveness of improving their physicochemical and biological properties by inoculating the roots with a solution of Methylobacterium and liquid compost in cauliflower cultivation, as well as integrating a treatment through an automated drip irrigation system. This biostimulant, biofertilizer, and biocontrol agent solution was used, which has applications in agriculture to improve soil health and crop productivity. The experiment was set up under a completely randomized block design with four treatments (T0, T1, T2, and T3), corresponding to doses of 0, 250, 333, and 400 mL per 200 L of water, respectively. The results indicated that treatment T3 significantly optimized the plant's physiological response to salt stress, increasing both its antioxidant capacity and chlorophyll α concentration. Likewise, physical characterization revealed significant differences in the morphological parameters of cauliflower, suggesting greater metabolic resistance and improved nutritional quality. Finally, ultrastructural analysis of the epidermis and stomata using microscopy showed that, while the control treatment (T0) had a collapsed surface, treatment T3 showed a functional and turgid ultrastructure. This demonstrates that the inoculation applied mitigates the phytotoxic impact of the substrate and optimizes the metabolic potential of the crop.

J. A. Legua Cárdenas, E. Macavilca Ticlayauri, M. S. Sánchez Calle et al. · 0 citations
Open access Aug 2026

Foliar Application of a Sargassum spp.-Based Biostimulant Improves Fruit Quality and Antioxidant Enzyme Activity in Melon

Seaweed-derived biostimulants are promising tools for improving crop performance and fruit quality in sustainable horticulture. This study evaluated the effects of foliar application of a liquid Sargassum spp. extract on the commercial quality, nutraceutical attributes, and antioxidant response of melon fruit (Cucumis melo L. cv. ‘Cruiser’). Four extract concentrations (0, 1.5, 3.0, and 4.5%, v/v) were applied in a randomized complete block design with six replications. Compared with the control, the 1.5% treatment increased (p ≤ 0.05) fruit firmness (33.5%), total soluble solids (25.4%), flesh thickness (16.5%), and ascorbic acid content (51.2%). Total phenolic and flavonoid contents also increased by 22.9% and 22.4%, respectively (p ≤ 0.05). Antioxidant enzyme activities increased in a concentration-dependent manner (p ≤ 0.05), highlighted by a 207.1% increase in catalase activity at 4.5% with catalase. In contrast, the highest concentration reduced carbohydrate content by 49.3% (p ≤ 0.05), while fruit yield remained unaffected (p > 0.05). Overall, 1.5% provided the best balance between commercial and nutraceutical quality while avoiding the adverse biochemical responses observed at 4.5%. These findings suggest the potential use of Sargassum spp. extract as a biostimulant for sustainable melon production under the conditions of this study.

Melisa C. Hermosillo-Alba, Bernardo Murillo-Amador, Alain Buendía-García et al. · 0 citations
Open access Jul 2026

Valorization of Citrus maxima Peel Waste Using Different Drying Methods: Phytochemical Profiling for Eco-Friendly Natural Fertilizer Development for Plant Growth

This study aims to optimize the utilization of Citrus maxima peel waste into an organic fertilizer rich in flavonoids and pectin by evaluating various drying methods. This optimization is undertaken as an effort to achieve sustainable agricultural waste management while creating value-added goods that enhance plant growth. The research treatments included of oven and sun-dried and three different types of solvents (n-hexane, ethanol, and ethyl acetate) with four replications. Pectin is extracted through acid heating and measured gravimetrically as calcium pectate. Macronutrients (N, K) is frequently analyzed using the Kjeldahl and Flame Photometry methods, whereas volatile substances are identified using GC-MS. The results show that sun drying maintains the highest pectin content (15.28%), but oven drying maintains the highest flavonoid content (237.25 mg CAE/g). Total Nitrogen (0.84%) and K2O (0.47%) content were higher in controlled oven-dried than in sun-dried samples. GC-MS analysis identified the compounds heneicosane, benzene, phenol, heptadecane, eicosane, and tetracosane as dominant when using non-polar n-hexane and ethyl acetate solvents. In contrast, ethanol solvents contained the dominant compounds is a-D-Mannofuranoside (mannofuranoside), hydroxymethylfurfural, and fatty acid. These compounds contribute to soil biological activity. The high nitrogen and potassium content in all analyzed samples confirms the suitability of Citrus maxima peel as an organic input for the development of environmentally friendly fertilizers. The integration of pectin as a nutrient carrier and its nitrogen & K2O profile, flavonoids, and rich metabolite contents indicate that the utilization of Citrus maxima peel has great potential and could serve as a sustainable alternative for the development of eco-friendly bio-based fertilizers to enhance plant growth, taking into considering the research findings that solvent polarity and drying conditions play a decisive role in shaping the metabolite profile of Citrus maxima peel extracts. Keywords: Citrus maxima, flavonoid, pectin, drying method, nutrient, GC-MS .

M. Kadir, N. Munir · 0 citations