New environmentally friendly bio-based micronutrient fertilizer by biosorption: From laboratory studies to the field

Electrodialysis treatment of rhamnolipids hydrolysate and its waste water for use as water-soluble fertilizer

Rhamnolipids can serve as a precursor for rhamnose production, but using ion exchange resin in purifying rhamnolipids hydrolysate results in excessive high-salinity wastewater, making the process environmentally and economically unfeasible. This study introduced electrodialysis technology as an alternative for purifying rhamnolipids hydrolysate, significantly reducing wastewater to less than 5 % compared to the resin method. To achieve zero wastewater discharge, the electrodialysis-treated wastewater was repurposed into a water-soluble fertilizer containing 7.1 g/L of rhamnolipids, 11.4 g/L of fatty acid, 2.4 g/L of amino acid, and 8.2 g/L of potassium. Unlike traditional fertilizers, the nutritional components with rhamnolipids showed remarkable potential in enhancing tomato plant growth, flowering, and fruit quality. Taken together, the electrodialysis treatment of rhamnolipids hydrolysate largely reduced the water volume, the economic cost, and took a full use of the final wastewater as efficient water-soluble fertilizers, making it applicable for large-scale rhamnose production.

Screening of Cu4 O3 NPs efficacy and its anticancer potential against cervical cancer

Cu4 O3 is the least explored copper oxide, and its nanoformulation is anticipated to have important therapeutic potential especially against cancer. The current study aimed to biosynthesize Cu4 O3 nanoparticles (NPs) using an aqueous extract of pumpkin seeds and evaluate its antiproliferative efficacy against cervical cells after screening on different cancer cell lines. The obtained NPs were characterized by different spectroscopic analyses, such as UV-vis, thermogravimetric, energy dispersive X-ray, and Fourier-transform infrared spectroscopy (FTIR). In addition, high-resolution transmission electron microscopes (HR-TEM) were used to observe the morphology of the biosynthesized NPs. The UV-vis spectra showed a peak at around 332 nm, confirming the formation of Cu4 O3 NPs. Moreover, FTIR and TAG analyses identified the presence of various bioactive phytoconstituents that might have worked as capping and stabilization agents and comparative stable NPs at very high temperatures, respectively. The HR-TEM data showed the spherical shape of Cu4 O3 NPs in the range of 100 nm. The Cu4 O3 NPs was screened on three different cancer cell lines viz., Hela, MDA-MB-231, and HCT-116 using cytotoxicity (MTT) reduction assay. In addition, Vero was taken as a normal epithelial (control) cell. The high responsive cell line in terms of least IC50 was further assessed for its anticancer potential using a battery of biological tests, including morphological alterations, induction of apoptosis/ROS generation, regulation of mitochondrial membrane potential (MMP), and suppression of cell adhesion/migration. Vero cells (control) showed a slight decline in % cell viability even at the highest tested Cu4 O3 NPs concentration. However, all the studied cancer cells viz., MDA-MB-231, HCT 116, and HeLa cells showed a dose-dependent decline in cell viability after the treatment with Cu4 O3 NPs with a calculated IC50 value of 10, 11, and 7.2 µg/mL, respectively. Based on the above data, Hela cells were chosen for further studies, that showed induction of apoptosis from 3.5 to 9-folds by three different staining techniques acridine orange/ethidium bromide (AO/EB), 4',6-diamidino-2-phenylindole (DAPI), and propidium iodide (PI). The enhanced production of reactive oxygen species (>3.5-fold), modulation in MMP, and suppression of cell adhesion/migration were observed in the cells treated with Cu4 O3 NPs. The current study obtained the significant antiproliferative potential of Cu4 O3 NPs against the cervical cancer cell line, which needs to be confirmed further in a suitable in vivo model. Based on our results, we also recommend the green-based, eco-friendly, and cost-effective alternative method for synthesizing novel nanoformulation.

Tannery waste as a renewable source of nitrogen for production of multicomponent fertilizers with biostimulating properties

The studies presented in this work show that solid tannery waste-like shavings can be used as high-protein materials for fertilizer production following the concept of the circular economy. To select appropriate process parameters (mass ratio of shavings meal to the hydrolyzing agent (S:L), hydrolysis medium concentration, temperature) and to ensure the highest possible hydrolysis efficiency, it is useful to apply the well-known response surface methodology (RSM). The analyses revealed that chromium shavings (SCr) were most preferably treated with 10% KOH in a ratio of S:L 1:1 with the process being carried out at 160 °C (6.59% N). The optimal hydrolysis conditions for non-chromium (S) shavings were: S:L ratio 1:2, 10% H₂SO₄, and temperature 160 °C (4.08% N). Chromium concentrations in hydrolysates from S and SCr shavings obtained under optimal conditions were 15.2 mg/kg and 9483 mg/kg, respectively. Hydrolysate samples were analyzed by reversed-phase high-pressure liquid chromatography (RP-HPLC) that revealed that the type of hydrolysis (acidic/alkaline) affects the amino acid profile. Approximately 4.5 times more amino acids were extracted in the KOH environment than during acidic treatment. The hydrolysates contained mainly glycine, alanine, and proline, which are primarily responsible for stimulating plant growth by supporting chlorophyll synthesis, chelating micronutrients, improving pollen fertility, or resistance to low temperatures. The conversion of tannery waste into fertilizer requires the control of contaminant levels, especially chromium, which can oxidize to the carcinogenic form Cr(VI) that is hazardous to humans and the environment.

Biomass-based micronutrient fertilizers and biofortification of raspberries fruits

The increasing amount of bio-waste creates the need to develop a method for efficient management based on processes that are more environmentally friendly than incineration and composting. This research aimed to utilize the waste of raspberry seeds after supercritical CO2 extraction. The biomass was enriched with micronutrients by the biosorption process to prepare micronutrient fertilizers for organic farming and biofortification of raspberries fruits. It was observed that at 100% dose of micronutrients, raspberry crop yield increased by 3%, and transfer of micronutrients to fruit biomass increased by 4.7%, 6.4%, and 8.8% (Cu, Mn, Zn, respectively) compared to commercial fertilizer. The supply of micronutrients at a dose of 150% led to a significant increase in micronutrient content of 3%, 41%, and 8% (Cu, Mn, and Zn, respectively) compared to commercial fertilizer. Research shows that the application of higher doses of micronutrients leads to the enrichment of edible parts of fruits, and fertilizers ensure environmental safety. The fruits contained on average 11.5% more microelements compared to the groups fertilized with the commercial product. The fruit yield (9.09-10.4 Mg per hectare) and the sugar content (9.82-10.2%) were also the highest. The micronutrients released from fertilizers and available to plants throughout the vegetation period affect the increase in yield, especially in the case of plants fruiting several times a year.

Innovative bio-waste-based multilayer hydrogel fertilizers as a new solution for precision agriculture

The aim of the research work was to present a multilayer hydrogel capsule with controlled nutrient release properties as an innovative fertilizer designed for sustainable agriculture. Preparation of the capsules included the following steps: sorption of micronutrients (Cu, Mn, Zn) on eggshells (1) and their immobilization in sodium alginate, with the crosslinking agent being the NPK solution (2). The capsules were coated with an additional layer of a mixture of biopolymers (0.79% alginate, 0.24% carboxymethylcellulose and 8.07% starch)by means of dipping and spraying techniques. The biocomposites were characterized by limited (<10% within 100 h for the structures encapsulated by the dipping method) release of fertilizer ions (except for small K⁺ ions). The hydrogel fertilizer formulations were analyzed for physicochemical properties such as macro- and micronutrient content, surface morphology analysis, coating structure evaluation, mechanical properties, swelling and drying kinetics. High nutrient bioavailability was confirmed in vitro (extraction in water and neutral ammonium citrate). Germination and pot tests have revealed that the application of multicomponent hydrogel fertilizers increases the length of cucumber roots by 20%, compared to the commercial product.

Innovative NPK Fertilizers based on Polyacrylamide and Polyvinyl Alcohol with Controlled Release of Nutrients

The aim of the present work was the preparation and properties evaluation of two innovative fertilizers based on multicomponent polymers characterized by a controlled release of nutrients. One method was based on a multi-component liquid containing different amounts of microelements NPK 12-5-6 fertilizers with polyacrylamide hydrogel beads. The second method concerned the cross-linking of biodegradable polyvinyl alcohol with multi-component NPK fertilizers. Polyacrylamide-based compositions with the highest amount of NPK salts as well as polyvinyl alcohol-based fertilizers in dense gel form, based on 60 phr crosslinking concentrate have shown optimal properties. Regardless of the type of fertilizers used, their components were released slowly. The obtained fertilizers were classified according to the kinetics of nutrient release. Fertilizers made from polyacrylamide based fertilizers have been classified into a group of controlled release fertilizers (CRF), while those made from biodegradable environmentally friendly polyvinyl alcohol have been defined as slow released fertilizers (SRF).

Tannery waste-derived biochar as a carrier of micronutrients essential to plants

The leather tannery industry generates about 33 Mt/year of solid waste with different properties, turning its management into a challenge. One of the valorization methods of tannery wastes is the production of biochar by pyrolysis of leather scratches. Biochar's sorption properties and its high nitrogen content (10%) make it suitable for its application as a soil conditioner or carrier of microelements for fertilizers. The paper presents an innovative spray method to enrich biochar with cationic micronutrients: Cu, Mn, Zn. Enriched biochar contained 1095 mg/kg Cu(II), 1334 mg/kg Mn(II) and 1205 mg/kg Zn(II). The high bioavailability of nutrients and the effectiveness of the new fertilizer were demonstrated in extraction in vitro tests - the analysis of leachability of elements to water and bioavailability of micro-nutrients. The functional properties of enriched biochar were examined in vivo (germination, pot) tests. A high biomass increase (approximately 10%) was observed compared to the group fertilized with a commercial product. The proposed solution benefits the environment in that it is made from alternative resources from which innovative fertilizers are produced according to the circular economy concept.

Valorization of poultry slaughterhouse waste for fertilizer purposes as an alternative for thermal utilization methods

Slaughterhouse waste and dead animals are mainly disposed of by incineration, which generates greenhouse gases and NO_x. These wastes are a source of nutrients that can be recovered by circular economy techniques if material recycling is given a priority over energy recovery. To valorize high-protein animal waste (containing bones, meat, feather) for fertilizer purposes, the waste was processed by acid solubilization and neutralized with potassium hydroxide solution, which yielded a liquid fertilizer with plant growth biostimulating properties (due to the amino acids presence). The composition analysis showed that new fertilizers met all quality requirements set by the law, contain ~0.5% m/m amino acids and are microbiologically pure. The fertilizer was enriched with microelements to the level of 0.2% m/m and tested for biological effectiveness in germination tests and field studies. Compared with the commercial formulation, the fertilizer increased stem length and chlorophyll content (by 8.2% and 27.0%, respectively), wheat crop yield and grain micronutrients density (Cu by 31.2%, Mn by 10.5%, Zn by 33.9%) and improved the wheat flour baking properties. The described solution propose a safe way to utilize hazardous waste via technological mobile installation, enabling no transportation of waste, which is an important aspect of sanitary-epidemiological risk minimization.

Hydrogel Alginate Seed Coating as an Innovative Method for Delivering Nutrients at the Early Stages of Plant Growth

Seed coating containing fertilizer nutrients and plant growth biostimulants is an innovative technique for precision agriculture. Nutrient delivery can also be conducted through multilayer seed coating. For this purpose, sodium alginate with NPK, which was selected in a preliminary selection study, crosslinked with divalent ions (Cu(II), Mn(II), Zn(II)) as a source of fertilizer micronutrients, was used to produce seed coating. The seeds were additionally coated with a solution containing amino acids derived from high-protein material. Amino acids can be obtained by alkaline hydrolysis of mealworm larvae (Gly 71.2 ± 0.6 mM, Glu 55.8 ± 1.3 mM, Pro 48.8 ± 1.5 mM, Ser 31.4 ± 1.5 mM). The formulations were applied in different doses per 100 g of seeds: 35 mL, 70 mL, 105 mL, and 140 mL. SEM-EDX surface analysis showed that 70 mL of formulation/100 g of seeds formed a continuity of coatings but did not result in a uniform distribution of components on the surface. Extraction tests proved simultaneous low leaching of nutrients into water (max. 10%), showing a slow release pattern. There occurred high bioavailability of fertilizer nutrients (even up to 100%). Pot tests on cucumbers (Cornichon de Paris) confirmed the new method’s effectiveness, yielding a 50% higher fresh sprout weight and four times greater root length than uncoated seeds. Seed coating with hydrogel has a high potential for commercial application, stimulating the early growth of plants and thus leading to higher crop yields.

New directions for agricultural wastes valorization as hydrogel biocomposite fertilizers

The tremendous amount of waste is an environmental and social problem worldwide. The agri-food sector is the largest producer of waste and requires the extensive use of fertilizers, which entails the need to look for innovative solutions in waste management. Properly recycled bio-waste can be reused as fertilizer. Polymer capsules with immobilized waste biomass can be applied as carriers for fertilizer nutrients. The amount of components exerts a certain influence on the effectiveness of copper ions binding. The most important physicochemical properties of biocomposites, such as swelling, SEM (Scanning Electron Microscopy) and FTIR (Fourier Transform Infrared Spectroscopy) were investigated. FTIR analyzes revealed that carboxyl and hydroxyl groups play a key role in Cu²⁺ ion binding. Morphology analysis showed that ion binding leads to homogenization of the composite surface, while coating the structure makes it more regular and cohesive. The sorption kinetics and the determination of the process's equilibrium parameters (Q_max = 29.4 ± 0.493 mg g^-1) play an important role. The study of Cu²⁺ ion release in different media showed that the chitosan layer slowed down the diffusion of cations by about 50% in NaNO₃ (1% m/m) solution. Preliminary studies of the applicability of the capsules in germination tests demonstrate that the biocomposites have no phytotoxic effects on the test plant. The chitosan coating slows the release of Cu²⁺ ions by about 20% compared to uncoated capsules. New fertilizer formulations containing chitosan-encapsulated hydrogel with biomass-immobilized micronutrients can be applied for precision agriculture to minimize the loss of fertilizer nutrients to the environment. These fertilizers could be used to cultivate houseplants and greenhouse crops.

Micronutrients encapsulation by starch as an enhanced efficiency fertilizer

Developing different paths to achieve sustainable agriculture is no longer an option; it is a necessity. EEF materials are alternatives to improve the efficacy of the agrochemicals in the soil and plant, reducing wasting and environmental contamination. The present work aims to develop EEF materials based on starch and micronutrients, considering few works address EEFs materials with micronutrients. Monoelementary dispersions of gelatinized starch with micronutrients (Fe, Cu, Mn) were spray-dried and thermally, structurally, and morphologically characterized. We evaluated water-medium nutrient release, release kinetics, and the swelling degree. Different micronutrients affect morphology, size distribution, swelling degree, release, kinetics, and interaction between polymer-nutrient. Bigger particle sizes achieved a higher swelling degree, which led to decreased micronutrient release in the water. The Peppas-Sahlin model mainly ruled the release kinetics (fitted to all the materials). This result confirmed our hypothesis that a swelling starch delays the release.

Role of bioengineering and laborers in integration of farmland resources toward to improve dimension of sustainable agriculture in China

Farmland transfer is one of the essential approaches for achieving large-scale farming and its management affects productive efficiency, environment pollution and food sustainable security supply. Present study was carried out investigation based representative agricultural development area Guanzhong Plain of Shaanxi, aimed at explore the role of biotechnology and laborers in integration of farmland toward to improve sustainable agriculture in rural China by employed the profit and Tobit models evaluation. The conclusion demonstrated that labor’s and agricultural management model as main stay, intensive farming has positive effect-based economic and environmental benefits than fragmentation management, female laborers have weaker effect on farmland renting-out behavior among smallholders while male laborers were superior promoters in increasing the area of rented-in farmland and farm scale. Finally, bioengineering development and agricultural intensification management as a rational choice that has great potential value for large-scale cultivation that contributing a promising future for achieving cleaner production, environment and human health further providing huge economic and social and environmental benefits in sustainability agriculture. Additionally, government policies require intensive intervention to accelerate large-scale management and biotechnology implementation.

Abbreviation: Aaflf: Average age of female labor force; Incom(log): Log of annual household income; Noflf: Number of women in the labor force; Nooaf: Number of old adults in family; NTFs: non-transfer families; OLS: ordinary least square; Palff: Proportion of agricultural laborers in the female labor force; Palmf: Proportion of agricultural laborers in the male labor force; RIFs: rented-in families; ROFs: rented-out families; Whhf: Whether the household head is female

Biosorption as a method of biowaste valorization to feed additives: RSM optimization

The aim of this work was to prepare an innovative microelemental feed additive for laying hens, based on waste biomass from the agricultural sector (alfalfa and goldenrod after CO₂ extraction in supercritical state). The process was optimized by Response Surface Methodology (RSM) and the most favourable enrichment conditions were selected for Cu(II), Mn(II) and Zn(II) ions: pH - 5, sorbate concentration of Cu(II), Mn(II), Zn(II) - 10.0 mg/L for alfalfa and 10.7 mg/L for goldenrod and biomass dose - 0.1 g/L. Physicochemical properties of biomass were studied and functional groups involved in the binding of Cu(II), Mn(II), Zn(II) ions were determined (mainly carboxylic and hydroxylic groups). An interesting and unique element of this work is the verification of the properties of prepared feed additives in conditions simulating the digestive tract of animals. The release of components in solutions simulating conditions in the intestine and stomach (pH 11 and pH 1) was tested (in vitro tests). The best desorption results were achieved at a strongly acidic pH which corresponds to the stomach environment: 9.80, 14.4% Cu(II), 69.0, 66.9% (Zn), 46.5, 31.9 Mn(II) for alfalfa and goldenrod, respectively. It was concluded that the biomass enriched with micronutrients in biosorption has the potential as a feed additive for sustainable agriculture.