Lignocellulosic biomass fertilizers: Production, characterization, and agri-applications.

The growing focus on sustainable agriculture and optimal resource utilization has spurred investigations into lignocellulosic biomass as a potential source for producing environmentally friendly fertilizers. This paper reviews recent advancements in the production and application of innovative fertilizers derived from lignocellulose. It highlights potential in enhancing agricultural productivity and reducing environmental impacts such as carbon footprint and water pollution. The paper outlines various methods for conversion, highlighting the unique advantages of chemical, enzymatic, and microbiological processes, for converting lignocellulosic biomass into nutrient-rich fertilizers. The study compares the efficacy of lignocellulosic fertilizers to traditional fertilizers in promoting crop growth, enhancing soil health, and reducing nutrient losses. The results demonstrate the potential of lignocellulosic biomass-derived fertilizers in promoting resource efficiency and sustainable agriculture. While this research significantly contributes to the existing body of knowledge, further studies on long-term impacts and scalability are recommended for the development of innovative and sustainable agricultural practices.

Valorization of poultry slaughterhouse waste into fertilizers with designed properties.

Climate change, soil erosion, air and water pollution, or problems related to waste management are just some of the many problems in the modern world. Comprehensive solutions are sought to reduce the effects of progressive environmental degradation according to the assumptions of the concept of sustainable development. The paper presents a technological concept that may be a response to these problems. The presented solution assumes full utilization of slaughterhouse waste with the simultaneous recovery of nutrients and the production of functional fertilizing products with designed properties. Four liquid fertilizer formulations with the following composition were prepared: N - 2.30-3.64%, P2O5 - 2.18-9.66%, and K2O - 0.11-4.49%. The manufactured products were characterized by a high sulfur content and the addition of microelements. The tests carried out on plants confirmed their effectiveness similar to commercial mineral fertilizers. An increase in green matter yield of peas by 5 t/ha and maize by 2 t/ha was observed. The lack of microbiological risk associated with their use has been proven. Good efficiency with a simultaneous reduction in production costs resulting from the use of waste materials, as well as limiting the negative impact of poultry farms on the environment, make this solution an attractive alternative to mineral fertilizers, in line with the assumptions of the circular economy.

Recent innovations in fertilization with treated digestate from food waste to recover nutrients for arid agricultural fields.

This study aims to explore the development of sustainable fertilizers from waste materials of a biogas plant and a brewery. These wastes, rich in organic carbon and nitrogen, were processed with sulfuric(VI) and phosphoric(V) acid mixture, facilitating the production of free amino acids and achieving waste sanitization. This treatment produced by-products, which extended the range of possible applications. The highest concentration of free amino acids (360 mg/l) was achieved through hydrolyzing with a 40% concentration medium over 24 h. In this case, the maximum levels were recorded for beta-alanine (69.3 mg/l), glycine (46.8 mg/l), isoleucine (43.5 mg/l), proline (36.2 mg/l), and valine (31.5 mg/l). The study presents two fertilizer technologies, with and without micronutrients, that satisfy European Parliament Regulation 2019/1009 (Ntot > 2%, Norg > 0.5%, Corg > 3%). Bioavailability of nutrients in the formulations ranged from 60 to 100%. The efficacies of these fertilizers were evaluated in 30-day pot trials with various plant species, with both single application and fertigation tested. Multielement analysis confirmed high nutrient transfer in the soil-plant system, and the inclusion of micronutrients led to biofortification of plant biomass in Cu (48.3 ± 7.2 mg/kg), Mn (249 ± 37 mg/kg), Zn (164 ± 25 mg/kg), and Fe (211 ± 32 mg/kg). These sustainable fertilizers present an alternative to traditional, non-renewable fertilizers and offer promising solutions for precision agriculture and environmentally conscious production.

Waste Valorization towards Industrial Products through Chemo- and Enzymatic- Hydrolysis.

This paper reviews the scientific literature on the latest technologies for treating waste by chemical hydrolysis, enzymatic hydrolysis and supporting processes. Particular attention is focused on wastes of biological origin, especially high-protein materials and those containing fats and sugars, as valuable components can be extracted from these recyclables to produce plant growth-stimulating compounds and animal feed, chemicals, biofuels or biopolymers. The wastes with the greatest potential were identified and the legislative regulations related to their processing were discussed. Chemical and enzymatic hydrolysis were compared and their main applications directions and important process parameters were indicated, as well as the need to optimize them in order to increase the efficiency of extraction of valuable components.

Maximizing the potential of leachate from sewage sludge as a sustainable nutrients source to alleviate the fertilizer crisis.

Leachate from separate digesters in biological wastewater treatment plants contains valuable biogenic compounds that can serve as fertilizer nutrients. In this study, a method was developed to utilize leachate from sewage sludge dewatering as a raw material for the preparation of a plant conditioner, providing water, nutrients, and growth-stimulating amino acids. A chemical conditioning procedure (65% HNO3) was used to prepare the leachate solution for fertilization. The feasibility of producing an amino acid-based fertilizer using shrimp shells and inorganic acids (96% H2SO4 and 85% H3PO4) was also demonstrated. Microbiological analysis confirmed the safety of the formulations, and chelation of micronutrients with available amino acids was proven (up to 100% chelating degree). The bioavailability of all nutrients was confirmed through extraction tests (extraction in neutral ammonium citrate). Germination tests showed similar fresh plant masses to those with commercial preparations, demonstrating the effectiveness of the developed technology. This approach aligns with circular economy principles and sustainable development and contributes to mitigating the impacts of climate change.

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.

Management of biological sewage sludge: Fertilizer nitrogen recovery as the solution to fertilizer crisis.

In the current situation of a serious raw material crisis related to the disruption of supply chains, the bioeconomy is of particular significance. Rising prices and the problem with the availability of natural gas have made N fertilizers production very expensive. It is expected that due to natural gas shortages, conventional production of nitrogen fertilizers by chemical synthesis will be hindered in the coming season. An important alternative and an opportunity to solve the problems of fertilizer nitrogen availability are biological wastewater treatment plants, which can be treated as a renewable biological nitrogen mines. Sewage sludge (including activated sludge) contains up to 6-8% DM. N. Considering the quantity of sewage sludge generated in wastewater treatment plants, it can become an important raw material for the sustainable production of organic-mineral fertilizers from renewable resources available locally, with a low carbon footprint. Furthermore, the sewage sludge management method should take nitrogen retention into account and should not allow the emission of greenhouse gases containing nitrogen. This article analyzes the technological solutions of nitrogen recovery for fertilization purposes from biological wastewater treatment plants in the context of a new and difficult resource situation. Conventional and new nitrogen recovery methods were analyzed from the perspective of the current legal situation. An attempt was made to evaluate the possibility of implementing the assumptions of the circular economy through the recovery of renewable nitrogen resources from municipal wastewater treatment plants.

Using greenhouse gases in the synthesis gas production processes: Thermodynamic conditions.

The work concerns the thermodynamic analysis of CH4 reforming with various oxidants (CO2, H2O, O2) in the technological variants DRM (Dry Reforming of Methane) and TRM (Tri-reforming of Methane) technological variants. Both processes of synthesis gas production (raw material for the production of value-added products) are problematic in terms of environmental protection. In the process, two components of greenhouse gases are used as a substrate: CO2 and CH4. The influence of temperature, pressure, and the molar ratio of oxidants to methane on the efficiency of both processes was analyzed using the deterministic method: raw material conversion, product efficiency and selectivity - H2 and CO, and the value of the H2/CO ratio characterizing the suitability of the synthesis gas for various syntheses. The problem of carbon deposition tendency in DRM was minimized through the selection of operational process conditions, and in the case of TRM, it was fully reduced. The deterministic method of non-linear programming by defining the objective function with constraints helped formulate allowed one the values of TRM parameters: complete reduction of the coking problem, maintaining the H2/CO ratio at the desired level - 2 and CO2 conversion equal to 90%, led to a hydrogen efficiency of over 90%. This efficiency can be obtained at the process temperature T = 273 K, with a pressure of 1 atm, and the molar ratios of oxidants to methane: CH4/CO2/H2O/O2 = 1/0.36/0.77/0.01.

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.

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.

Recent innovations in various methods of harmful gases conversion and its mechanism in poultry farms.

Poultry breeding takes place in intensive, high-production systems characterized by high animal density, which is a source of harmful emission of odorous volatile organic compounds (VOCs), ammonia (NH3), hydrogen sulfide (H2S) and greenhouse gases, which in turn sustain animal welfare. This study identified and examined the characteristics of chemical compounds emitted in intensive poultry farming (laying hens, broilers) and their toxicity, which led to recommending methods of deodorization. Emphasis was placed on the law relative to air purification in poultry farms. Various methods of air treatment in poultry farms have been described: the modification of animal diet to improve nutrient retention and decrease the amount of their excrement; chemical oxidation technologies (ozonation, photocatalysis, Fenton reaction); various types/brands of biofilters, bioscrubbers and membrane reactors. Numerous studies show that biofilters can reduce ammonia emissions by 51%, hydrogen sulfide by 80%, odors by 67%, while scrubbers brings down ammonia emissions by 77% and odors by 42%, and the application of UV light lowers ammonia emissions by 28%, hydrogen sulfide by 55%, odors by 69% and VOCs by 52%. The paper presents both the solutions currently used in poultry farming and those which are currently in the research and development phase and, as innovative solutions, could be implemented in the near future.

From hazardous waste to fertilizer: Recovery of high-value metals from smelter slags.

This work proposes a method to valorize lead slag for fertilizer purposes. The research concept was to selectively recover valuable microelements (Cu(II), Fe(II), Zn(II) in an amount of at least 0.2% m/v of each) by chemical leaching while retaining toxic elements in the slag (i.e. As and Pb). Among acids, hydroxides, salts and their mixtures tested for slag treatment, it was potassium hydrogen sulfate and ammonia liquor under strongly oxidizing conditions (in the presence of hydrogen peroxide) that proved to be the most effective leaching agents. Response Surface Methodology applied to optimize the slag leaching conditions set the most favorable process parameters (concentration of leaching agents, slag to reagent weight ratio, and temperature). As a result, the concentration of Cu(II) in the extract was 3751 mg/L (for ammonia liquor) and Fe(II) and Zn(II) concentrations in potassium hydrogen sulfate were 4738 mg/L and 6102 mg/L, respectively. To close the life cycle of the waste, immobilization in polyethylene and binding to cement were indicated as methods to manage the solid waste material after leaching. The mixed extracts rich in Cu(II), Fe(II) and Zn(II) ions were tested in germination tests on cucumber. No phytotoxic effect was observed, which raises the possibility of utilizing the solutions after chemical leaching of slag as an alternative source of micronutrients for the production of multicomponent fertilizers. The results are promising and fit in the assumptions of circular economy.

Biochar in environmental friendly fertilizers - Prospects of development products and technologies.

According to the circular economy concept, the production of fertilizers should be closed in a loop, which prevents excessive emissions and harmful effects to the environment. Biological wastes are problematic to collect and transport. They undergo a biological transformation that causes greenhouse gases emission and sanitary hazards. Biomass sources used for organic or organo-mineral fertilizers must be free of pathogens and rich in macro and microelements. Solid residues can be processed thermally. Biochar is a carbon produced by biomass pyrolysis without oxygen presence and has been used for many years to improve soil quality and enhance the efficiency of fertilization. There are many research works on the use of biochar in fertilization. This study is also extended by the latest developments and technologies from the patent database (recent year) and biochar-based fertilizers market. To the best of our knowledge, there is no such review currently available in scientific databases. Based on the collected data, the best method of biochar management was proposed - soil application. Biochar applied to soil has several advantages: it improves soil structure and its sorption capacity, enhances soil-nutrient retention and water-holding capacity, immobilizes contaminants from soil (sorption), reduces greenhouse gas emissions and soil nutrient leaching losses while stimulating the growth of a plant.

Biodegradation of pharmaceuticals in photobioreactors - a systematic literature review.

This work is a systematic review that reports state-of-the-art in removal of pharmaceuticals from water and wastewater by photosynthetic organisms in photobioreactors. The PRISMA protocol-based review of the most recent literature data from the last 10 years (2011-2021) was reported. Articles were searched by the combination of the following keywords: photobioreactor, pharmaceuticals, drugs, hormones, antibiotics, biodegradation, removal, wastewater treatment. The review focuses on original research papers (not reviews), collected in 3 scientific databases: Scopus, Web of Knowledge, PubMed. The review considered the following factors: type of microorganisms, type of micropollutants removed, degradation efficiency and associated products, types of photosynthetic organisms and photobioreactor types. The conclusion from the systematic review is that the main factors that limit widespread pharmaceuticals removal in photobioreactors are high costs and the problem of low efficiency related with low concentrations of pharmaceuticals. The review indicated a need for further research in this area due to increasing amounts of metabolites in the food chain, such as p-aminophenol and estrone, which can cause harm to people and ichthyofauna. Pharmaceuticals removal can be improved by adapting the type of microorganism used to the type of contamination and implementing photoperiods, which increase the removal efficiency of e.g. sulfamethazine by up to 28%. In the future, it is necessary to search for new solutions in terms of the construction of photobioreactors, as well as for more effective species in terms of pharmaceuticals biodegradation that can survive the competition with other strains during water and wastewater treatment.

The challenges and perspectives for anaerobic digestion of animal waste and fertilizer application of the digestate.

The increase in livestock production creates a serious problem of managing animal waste and by-products. Among the wide range of waste valorization methods available, anaerobic digestion is very promising. It is a form of material recycling that also produces renewable energy in the form of biogas, which is reminiscent of energy recycling. The effluent and digestate from the anaerobic digestion process need to be processed further. These materials are widely used in agriculture due to their composition. Both the liquid and solid fractions of digestate are high in nitrogen, making them a valuable source for plants. Before soil or foliar application, conditioning (e.g., with inorganic acids) and neutralization (e.g., with potassium hydroxide) is required to eliminate odorous compounds and microorganisms. Various methods of conducting the process by anaerobic digestion (use of additives increasing activity of microorganisms, co-digestion, multiple techniques of substrate preparation) and the possibility of controlling process parameters such as optimal C/N ratio (15-30), optimal temperature (psychrophilic (<20 °C), mesophilic (35-37 °C) and thermophilic (55 °C) for microorganism activity ensure high efficiency of the process. Literature data describing tests of various digestates on different plants prove high efficiency, determined by yield increase (even by 28%), nitrogen uptake (by 20%) or phosphorus recovery rate (by 43%) or increase of biometric parameters (e.g., leaf area).

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 NOx. 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.

Antiviral Properties of Polyphenols from Plants.

Polyphenols are active substances against various types of viral infections. Researchers have characterized methods of how to isolate polyphenols without losing their potential to formulate pharmaceutical products. Researchers have also described mechanisms against common viral infections (i.e., influenza, herpes, hepatitis, rotavirus, coronavirus). Particular compounds have been discussed together with the plants in the biomass in which they occur. Quercetin, gallic acid and epigallocatechin are exemplary compounds that inhibit the growth cycle of viruses. Special attention has been paid to identify plants and polyphenols that can be efficient against coronavirus infections. It has been proven that polyphenols present in the diet and in pharmaceuticals protect us from viral infections and, in case of infection, support the healing process by various mechanisms, i.e., they block the entry into the host cells, inhibit the multiplication of the virus, seal blood vessels and protect against superinfection.

Valorization of postextraction residues-analysis of the influence of new feed additives with micronutrients on eggs quality parameters.

This paper presents attempts to enrich hens eggs with ions of copper, manganese, and zinc through the use of new feed additives (19 mg Cu2+; 124 mg Mn2+ and 85 mg Zn2+) such as biomass of alfalfa and goldenrod after extraction with supercritical carbon dioxide enriched with microelements via biosorption. Mechanical parameters of eggs (shell thickness and strength, Haugh unite), hen's laying performance, microelements content in albumen and yolk were examined and the transfer factor from feed to eggs was determined. The highest transfer of microelements content in albumen occurred in the group of hens fed with enriched goldenrod in a 100% dose (daily dose of microelements from biomass; Cu2+ 106%; Mn2+ 104%; Zn2+ 104% more in comparison to the inorganic salt group), while the highest yolk enrichment with microelements manifested itself for hens fed with enriched goldenrod in a 50% dose (daily dose of microelements from biomass; Cu2+ 32%; Zn2+ 22% more in comparison to the inorganic salt group). These groups also had the highest total microelements concentration. Mechanical properties of eggs varied insignificantly during the trial. Production parameters did not differ statistically among all experimental group. Eggs produced with need additives had better organoleptic parameters than fed with conventional premixes, which is why they were preferred by the respondents. The presented technology allows obtaining low-cost feed materials characterized by high bioavailability of components. The produced feed additives can serve as potential material for biofortification of eggs with nutrients.