Groundnut shell -a beneficial bio-waste

Valorization of Agriculture Residues into Value-Added Products: A Comprehensive Review of Recent Studies

Global agricultural by-products usually go to waste, especially in developing countries where agricultural products are usually exported as raw products. Such waste streams, once converted to "value-added" products could be an additional source of revenue while simultaneously having positive impacts on the socio-economic well-being of local people. We highlight the utilization of thermochemical techniques to activate and convert agricultural waste streams such as rice and straw husk, coconut fiber, coffee wastes, and okara power wastes commonly found in the world into porous activated carbons and biofuels. Such activated carbons are suitable for various applications in environmental remediation, climate mitigation, energy storage, and conversions such as batteries and supercapacitors, in improving crop productivity and producing useful biofuels.

Bioactive compounds of peanut skin in prevention and adjunctive treatment of chronic non-communicable diseases

The global prevalence of cancer continues to increase, so does its mortality. Strategies that can prevent/treat this condition are therefore required, especially low-cost and low-toxicity strategies. Bioactive compounds of plant origin have been presented as a good alternative. In this scenario, due to its abundant polyphenolic content (around 60 to 120 times greater than that of the grain), peanut skin by-products stand out as a sustainable source of food bioactives beneficial to human health. Investigated studies highlighted the importance of peanut skin for human health, its phytochemical composition, bioactivity and the potential for prevention and/or adjuvant therapy in cancer, through the advanced search for articles in the Virtual Health Library (VHL), Science direct and the Mourisco platform of the FioCruz Institute, from 2012 to 2022. Using the keywords, "peanut skin" AND "cancer" AND NOT "allergy", the words "peanut testa" and "peanut peel" were included replacing "peanut skin". 18 articles were selected from Plataforma Mourisco, 26 from Science Direct and 26 from VHL. Of these, 7 articles evaluated aspects of cancer prevention and/or treatment. Promising benefits were found in the prevention/treatment of chronic non-communicable diseases in the use of peanut and peanut skin extracts, such as cholesterolemia and glucose control, attenuation of oxidative stress and suppressive action on the proliferation and metabolism of cancer cells.

Comparison of Oil-Seed Shell Biomass-Based Biochar for the Removal of Anionic Dyes-Characterization and Adsorption Efficiency Studies

This research investigated the synthesis of biochar through the direct pyrolysis of pre-roasted sunflower seed shells (SFS) and peanut shells (PNS) and compared their application for the effective removal of textile dyes from wastewater. Biochar prepared at 900 °C (SFS900 and PNS900) showed the highest adsorption capacity, which can be attributed to the presence of higher nitrogen content and graphite-like structures. CHNS analysis revealed that PNS900 exhibited an 11.4% higher carbon content than SFS900, which enhanced the environmental stability of PNS biochar. Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses of the produced biochar indicated the degradation of cellulosic and lignin moieties. X-ray photoelectron spectroscopy (XPS) revealed a 13.8% and 22.6% increase in C-C/C=C mass concentrations in the SFS900 and PNS900, respectively, and could be attributed to the condensation of polyaromatic structures. Batch experiments for dye removal demonstrated that irrespective of dye species, PNS900 exhibited superior dye removal efficiency compared to SFS900 at similar dosages. In addition to H-bonding and electrostatic interactions, the presence of pyridinic-N and graphitic-N can play a vital role in enhancing Lewis acid-base and π-π EDA interactions. The results can provide valuable insights into the biochar-dye interaction mechanisms.

Immobilizing white-rot fungi laccase: Toward bio-derived supports as a circular economy approach in organochlorine removal

Despite their high persistence in the environment, organochlorines (OC) are widely used in the pharmaceutical industry, in plastics, and in the manufacture of pesticides, among other applications. These compounds and the byproducts of their decomposition deserve attention and efficient proposals for their treatment. Among sustainable alternatives, the use of ligninolytic enzymes (LEs) from fungi stands out, as these molecules can catalyze the transformation of a wide range of pollutants. Among LEs, laccases (Lac) are known for their efficiency as biocatalysts in the conversion of organic pollutants. Their application in biotechnological processes is possible, but the enzymes are often unstable and difficult to recover after use, driving up costs. Immobilization of enzymes on a matrix (support or solid carrier) allows recovery and stabilization of this catalytic capacity. Agricultural residual biomass is a passive environmental asset. Although underestimated and still treated as an undesirable component, residual biomass can be used as a low-cost adsorbent and as a support for the immobilization of enzymes. In this review, the adsorption capacity and immobilization of fungal Lac on supports made from residual biomass, including compounds such as biochar, for the removal of OC compounds are analyzed and compared with the use of synthetic supports. A qualitative and quantitative comparison of the reported results was made. In this context, the use of peanut shells is highlighted in view of the increasing peanut production worldwide. The linkage of methods with circular economy approaches that can be applied in practice is discussed.

A narrative action on the battle against hunger using mushroom, peanut, and soybean-based wastes

Numerous generations have been affected by hunger, which still affects hundreds of millions of people worldwide. The hunger crisis is worsening although many efforts have been made to minimize it. Besides that, food waste is one of the critical problems faced by most countries worldwide. It has disrupted the food chain system due to inefficient waste management, while negatively impacting the environment. The majority of the waste is from the food production process, resulting in a net zero production for food manufacturers while also harnessing its potential. Most food production wastes are high in nutritional and functional values, yet most of them end up as low-cost animal feed and plant fertilizers. This review identified key emerging wastes from the production line of mushroom, peanut, and soybean (MPS). These wastes (MPS) provide a new source for food conversion due to their high nutritional content, which contributes to a circular economy in the post-pandemic era and ensures food security. In order to achieve carbon neutrality and effective waste management for the production of alternative foods, biotechnological processes such as digestive, fermentative, and enzymatic conversions are essential. The article provides a narrative action on the critical potential application and challenges of MPS as future foods in the battle against hunger.

Modification of Epoxy Compositions by the Application of Various Fillers of Natural Origin

A series of composites based on epoxy resin filled with additives of natural origin were prepared to investigate the influence of such fillers on the properties of the epoxy compositions. For this purpose, the composites containing 5 and 10 wt.% of additive of natural origin were obtained using the dispersion of oak wood waste and peanut shells in bisphenol A epoxy resin cured with isophorone-diamine. The oak waste filler had been obtained during the assembly of the raw wooden floor. The performed studies include testing of samples prepared using unmodified and chemically modified additives. Chemical modification via mercerization and silanization was performed to increase the poor compatibility between the highly hydrophilic fillers of natural origin and the hydrophobic polymer matrix. Additionally, the introduction of NH₂ groups to the structure of modified filler via 3-aminopropyltriethoxysilane, potentially takes a part in co-crosslinking with the epoxy resin. Fourier Transformed Infrared Spectroscopy (FT-IR), as well as Scanning Electron Microscopy (SEM), were carried out, to study the influence of performed chemical modification on the chemical structure and morphology of wood and peanut shell flour. SEM analyses showed significant changes in the morphology of compositions with chemically modified fillers, indicating improved adhesion of the resin to lignocellulosic waste particles. Moreover, a series of mechanical (hardness, tensile strength, flexural strength, compressive strength, and impact strength) tests were carried out, to assess the influence of the application of fillers of natural origin on the properties of epoxy compositions. All composites with lignocellulosic filler were characterized by higher compressive strength (64.2 MPa-5%U-OF, 66.4%-SilOF, 63.2-5%U-PSF, and 63.8-5%SilPSF, respectively), compared to the values recorded for the reference epoxy composition without lignocellulosic filler (59.0 MPa-REF). The highest compressive strength, among all tested samples, was recorded for the composite filled with 10 wt.% of unmodified oak flour (69.1 MPa-10%U-OF). Additionally, higher values of flexural and impact strength, concerning pure BPA-based epoxy resin, were recorded for the composites with oak filler (respectively, flexural strength: 73.8 MPa-5%U-OF and 71.5 MPa-REF; impact strength: 15.82 kJ/m²-5%U-OF, 9.15 kJ/m²-REF). Epoxy composites with such mechanical properties might be considered as broadly understood construction materials. Moreover, samples containing wood flour as a filler exhibit better mechanical properties compared to those with peanut shell flour (tensile strength for samples containing post-mercerization filler: 48.04 MPa and 40.54 MPa; while post-silanization 53.53 MPa and 42.74 MPa for compositions containing 5 wt.% of wood and peanut shell flour, respectively). At the same time, it was found that increasing the weight share of flour of natural origin in both cases resulted in the deterioration of mechanical properties.

An overview of mechanical and corrosion properties of aluminium matrix composites reinforced with plant based natural fibres

Many researchers have become more interested in utilizing plant based natural fibre as reinforcement for the fabrication of aluminium matrix composites (AMCs) in recent time. The utilization of these environmentally friendly and cost effective plant based natural fibre is necessitated to avoid environmental pollution. The desire for cost-effective and low-cost energy materials in automotive, biomedical, aerospace, marine, and other applications, however, is redefining the research environment in plant based natural fibre metal matrix composite materials. As a result, the goal of this review study is to investigate the impact of agricultural waste-based reinforcements on the mechanical properties and corrosion behaviour of AMCs made using various fabrication routes. Processing settings can be modified to produce homogenous structures with superior AMC characteristics, according to the findings. Plant based natural fibre ash reinforcing materials such as palm kernel shell ash, rice husk ash, sugarcane bagasse, bamboo stem ash, and corn cob ash can reduce AMCs density without sacrificing mechanical qualities. Furthermore, efficient utilization of plant based natural fibre reduces manufacturing costs and prevents environmental pollution, making it a sustainable material. Brittle composites , unlike ceramic and synthetic reinforced composites, are not formed by plant based natural fibre reinforcements. As a result of our findings, plant based natural fibre AMCs have a high potential to replace expensive and hazardous ceramic and synthetic reinforced-AMCs, which can be used in a variety of automotive applications requiring lower cost, higher strength-to-weight ratio, and corrosion resistance.

A remediation approach to chromium-contaminated water and soil using engineered biochar derived from peanut shell

Hexavalent chromium (Cr[VI]) is one of the major environmental concerns due to its excessive discharge through effluents from the leather tanning industry. Peanut production leads to the generation of residual shells as waste calling for sustainable disposal. In this study, we employed an innovative approach of applying peanut-shell-derived pristine and engineered biochar for the remediation of Cr-contaminated wastewater and soil. The peanut shell waste was converted to biochar, which was further engineered with cetyltrimethylammonium bromide (CTAB, a commonly used cationic surfactant). The biochars were then used for the adsorption and immobilization of Cr(VI) in water and soil, respectively. The adsorption experiments demonstrated high Cr(VI) removal efficiency for the engineered biochar (79.35%) compared with the pristine biochar (37.47%). The Langmuir model best described the Cr(VI) adsorption onto the biochars (R² > 0.97), indicating monolayer adsorption. Meanwhile, the adsorption kinetics indicated that chemisorption was the dominant mechanism of interaction between the Cr(VI) and the biochars, as indicated by the best fitting to the pseudo-second-order model (R² > 0.98). Adsorption through the fixed-bed column also presented higher Cr(VI) adsorption onto the engineered biochar (q_eq = 22.93 mg g^-1) than onto the pristine biochar (q_eq = 18.54 mg g^-1). In addition, the desorption rate was higher for the pristine biochar column (13.83 mg g^-1) than the engineered biochar column (10.45 mg g^-1), indicating that Cr(VI) was more strongly adsorbed onto the engineered biochar. A higher immobilization of Cr(VI) was observed in the soil with the engineered biochar than with the pristine biochar, as was confirmed by the significant decreases in the Cr(VI) bioavailability (92%), leachability (100%), and bioaccessibility (97%) compared with the control (soil without biochar). The CTAB-engineered biochar could thus potentially be used as an efficient adsorbent for the removal and the immobilization of Cr(VI) in water and soil, respectively.

Roadmap of Effects of Biowaste-Synthesized Carbon Nanomaterials on Carbon Nano-Reinforced Composites

Sustainable growth can be achieved by recycling waste material into useful resources without affecting the natural ecosystem. Among all nanomaterials, carbon nanomaterials from biowaste are used for various applications. The pyrolysis process is one of the eco-friendly ways for synthesizing such carbon nanomaterials. Recently, polymer nanocomposites (PNCs) filled with biowaste-based carbon nanomaterials attracted a lot of attention due to their enhanced mechanical properties. A variety of polymers, such as thermoplastics, thermosetting polymers, elastomers, and their blends, can be used in the formation of composite materials. This review summarizes the synthesis of carbon nanomaterials, polymer nanocomposites, and mechanical properties of PNCs. The review also focuses on various biowaste-based precursors, their nanoproperties, and turning them into proper composites. PNCs show improved mechanical properties by varying the loading percentages of carbon nanomaterials, which are vital for many defence- and aerospace-related industries. Different synthesis processes are used to achieve enhanced ultimate tensile strength and modulus. The present review summarizes the last 5 years’ work in detail on these PNCs and their applications.

Ligninolytic enzymes production during polycyclic aromatic hydrocarbons degradation: effect of soil pH, soil amendments and fungal co-cultivation

Soil microorganisms play an important role in the degradation of PAHs and use various metabolic pathways for this process. The effect of soil pH, different soil amendments and the co-cultivation of fungi on the degradation of PAHs in soil and on the activity of ligninolytic enzymes was evaluated. For that purpose, three fungi were studied: Trichoderma viride, Penicillium chrysogenum and Agrocybe aegerita. Biodegradation assays with a mixture of 200 ppm PAHs (fluorene, pyrene, chrysene, and benzo[a]pyrene-50 ppm each) were set up at room temperature for 8 weeks. The maximum laccase activity by solid state fermentation-SSF (7.43 U/g) was obtained by A. aegerita on kiwi peels with 2 weeks and the highest manganese peroxidase activity (7.21 U/g) was reached in 4 weeks, both at pH 7. Fluorene, pyrene, and benzo[a]pyrene achieved higher degradation rates in soil at pH 5, while chrysene was more degradable at pH 7. About 85-90% of the PAHs were degraded by fungal remediation. The highest degradation of fluorene was achieved by co-cultivation of A. aegerita and P. chrysogenum, remaining 14% undegradable. Around 13% of pyrene stay undegradable by A. aegerita and T. viride and by A. aegerita and P. chrysogenum, both systems supported in kiwi peels, while 11% of chrysene remained in soil by the co-cultivation of these fungi, supported by peanut shells. Regarding benzo[a]pyrene, 13% remained in soil after treatment with A. aegerita. Despite the increase in degradation of some PAHs with co-cultivation, higher enzyme production during degradation was observed when fungi were cultivated alone.

Bioactivity assessment of exopolysaccharides produced by Pleurotus pulmonarius in submerged culture with different agro-waste residues

Pleurotus spp. are white-rot fungi that utilize different agro-wastes to produce useful biologically active compounds. In this study, exopolysaccharides (EPS) were produced by Pleurotus pulmonarius in submerged culture supplemented with different agro-wastes. Functional groups in EPS were revealed using Fourier Transform-Infrared (FT-IR) spectroscopy. Antimicrobial activity of EPS was tested against microorganisms using agar well diffusion. Scavenging potentials of EPS was tested against 1, 1- diphenyl-2-picryhydrazyl (DPPH), hydroxyl (OH), iron (Fe2+) and nitric oxide (NO) radicals. In vitro prebiotic activity of EPS was carried out. The highest yield (5.60 g/L) of EPS was produced by P. pulmonarius in submerged culture supplemented with groundnut shell (20.0 g/L). The functional groups in EPS were hydroxyl (-OH), methyl (-CH3), ketone (-RCOH) and carbonyl group (-C=O). EPS displayed zones of inhibition (5.00-14.00 mm) against tested microorganisms. Scavenging activity of EPS ranged from 65.70-81.80% against DPPH. EPS supported the growth of Lactobacillus delbrueckii and Streptococcus thermophiles with values ranged from 3.04 × 104-3.40 × 104 cfu/ml and 2.50 × 104-2.81 × 104 cfu/ml, respectively. Submerged culture of P. pulmonarius with addition of agro-wastes enhanced yield of EPS. The EPS exhibited bio-functional properties like antimicrobial, antioxidant and prebiotic activities. Hence, agrowastes can be recycled in submerged fermentation with fungi to produce promising biomaterials for biopharmaceutical applications.

Collection of recyclable wastes within the scope of the Zero Waste project: heterogeneous multi-vehicle routing case in Kirikkale

There is an increase in the amount of resource use due to the rise in population, urbanization, and industrialization. Also, the amount of waste increases due to an increase in consumption and resource use. Countries are developing new policies depending on both decreasing resources and environmental problems caused by waste. The "Zero Waste" project was launched to recycle waste and to reduce environmental pollution in Turkey. The project aims to separate recyclable waste at its source and recycle them. One of the problems encountered in the implementation of the project is collecting the waste from temporary storage areas. In this study, the problem of transportation of wastes from temporary warehouses to the main warehouse was discussed in Kırıkkale/Turkey. A three-step solution approach has been proposed to the solution of the problem. In the first stage, the amounts of waste generated at the addresses to collect were estimated. In the second stage, the addresses to be visited are classified with an approach based on Pareto analysis according to the calculated waste amounts. According to this classification, it is planned which addresses will be visited on which day of the week. At the last stage, the problem is modeled as a heterogeneous multi-vehicle routing problem, which also takes into account the daily working hours and vehicle capacity constraints. According to the result of the mathematical model, the number of vehicles needed for waste collection, the types of vehicles, and the routes of the vehicles were found. Considering the implementation stages of the Zero Waste project, three different case studies are handled for Kırıkkale. These case studies have been solved by considering different waste rates. According to the results, the waste collection plan was made economically by visiting fewer spots in a week.