Tons Of By-products Research Articles

Sea Buckthorn Leaves as a Potential Source of Antioxidant Substances

Each year, agro-foods produce thousands of tonnes of by-products that contain high-value, unique nutrients. The application of plant by-products enables agro-food corporations to obtain value from them and avoid using natural resources. The idea of the bio economy protects against environmental pollution and leads to a cheap source of bioactive components, which can be transformed into value-added products for other industries. The numerous publications on the positive impact of sea buckthorn (SBT, Hippophae rhamnoides L., Elaeagnaceae family) and its products on human health mainly concern its fruits and seeds. However, there are few data relating to the properties of SBT leaves. The leaves of SBT can be a rich source of nutrients and biologically active substances. In this investigation, we report the study of the leaves of four SBT cultivars. We determined their antioxidant capacities, measured total polyphenols and total flavonoids, and quantified their major polyphenols and alkaloids. The results show that SBT leaves are a source of antioxidants and alkaloids. Additionally, in this raw material, we identified the presence of individual flavonols (rutoside and quercetin), individual anthocyanidins (cyaniding, delphinidin, and peonidin), and chelerythrine by high-performance thin-layer chromatography (HPTLC) for the first time. Through these types of studies, we aim to revalue this raw material, which is not well known in the world. Considering its nutritional properties, we seek to increase the use of its high-value, unique nutrients in food processing, medicine, and animal nutrition, in accordance with the goals of a closed-loop bioeconomy.

Unveiling the Chemistry of Citrus Peel: Insights into Nutraceutical Potential and Therapeutic Applications.

The recent millennium has witnessed a notable shift in consumer focus towards natural products for addressing lifestyle-related disorders, driven by their safety and cost-effectiveness. Nutraceuticals and functional foods play an imperative role by meeting nutritional needs and offering medicinal benefits. With increased scientific knowledge and awareness, the significance of a healthy lifestyle, including diet, in reducing disease risk is widely acknowledged, facilitating access to a diverse and safer diet for longevity. Plant-based foods rich in phytochemicals are increasingly popular and effectively utilized in disease management. Agricultural waste from plant-based foods is being recognized as a valuable source of nutraceuticals for dietary interventions. Citrus peels, known for their diverse flavonoids, are emerging as a promising health-promoting ingredient. Globally, citrus production yields approximately 15 million tons of by-products annually, highlighting the substantial potential for utilizing citrus waste in phyto-therapeutic and nutraceutical applications. Citrus peels are a rich source of flavonoids, with concentrations ranging from 2.5 to 5.5 g/100 g dry weight, depending on the citrus variety. The most abundant flavonoids in citrus peel include hesperidin and naringin, as well as essential oils rich in monoterpenes like limonene. The peel extracts exhibit high antioxidant capacity, with DPPH radical scavenging activities ranging from 70 to 90%, comparable to synthetic antioxidants like BHA and BHT. Additionally, the flavonoids present in citrus peel have been found to have antioxidant properties, which can help reduce oxidative stress by 30% and cardiovascular disease by 25%. Potent anti-inflammatory effects have also been demonstrated, reducing inflammatory markers such as IL-6 and TNF-α by up to 40% in cell culture studies. These findings highlight the potential of citrus peel as a valuable source of nutraceuticals in diet-based therapies.

Development of a New Kombucha from Grape Pomace: The Impact of Fermentation Conditions on Composition and Biological Activities

Winemaking is one of the oldest biotechnology techniques in the world. The wine industry generates 20 million tons of by-products, such as wastewater, stalk, lees, pomace, and stems, each year. The objective of this research project is to valorize wine industry by-products by producing a functional beverage via the fermentation of grape pomace with the kombucha consortium. In this study, grape pomace kombucha was produced under different conditions, and the concentration of the added sucrose in addition to the fermentation duration and temperature were varied. Overall, fermentation was characterized by the consumption of sugars and the production of organic acids and ethanol. An improvement in the concentrations of the total polyphenols and anthocyanins was observed in the developed product (i.e., up to 100%). Moreover, an enhancement of the antioxidant potential by 100%, as well as increases of 50 to 75% in the anti-inflammatory and antidiabetic activities, was noted.

Ultrasound assisted extraction and liposome encapsulation of olive leaves and orange peels: How to transform biomass waste into valuable resources with antimicrobial activity

Every year million tons of by-products and waste from olive and orange processing are produced by agri-food industries, thus triggering environmental and economic problems worldwide. From the perspective of a circular economy model, olive leaves and orange peels can be valorized in valuable products due to the presence of bioactive compounds such as polyphenols exhibiting beneficial effects on human health.The aqueous extracts of olive leaves and orange peels rich in phenolic compounds were prepared by ultrasound-assisted extraction. Both extracts were characterized in terms of yield of extraction, total phenolic content and antioxidant capacity; the polyphenolic profiles were deeper investigated by HPLC-MS analysis.Each extract was included in liposomes composed by a natural phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine,and cholesterol prepared according to the thin-layer evaporation method coupled with a sonication process.The antimicrobial activity of the extracts, free and loaded in liposomes, was investigated according to the broth macrodilution method against different strains of potential bacterial pathogenic species: Staphylococcus aureus (NCIMB 9518), Bacillus subtilis (ATCC 6051) and Enterococcus faecalis (NCIMB 775) as Gram-positive, while Escherichia coli (NCIMB 13302), Pseudomonas aeruginosa (NCIMB 9904) and Klebsiella oxytoca (NCIMB 12259) as Gram-negative.The encapsulation of olive leaves extract in liposomes enhanced its antibacterial activity against S. aureus by an order of magnitude.

Forage Properties of Fresh and Composted Cotton Gin Byproducts as Feed Supplements

Cotton ginning generates millions of tons of byproducts every year. If not properly managed, these materials become waste, which may constitute significant environmental, economic, and logistical issues. The objectives of this study were to characterize fresh and composted cotton gin byproducts (CGBs) for utilization as animal feed supplements and investigate the effects of composting on the forage properties. The study analyzed and compared the nutrients and energy contents of fresh and composted CGB from four commercial cotton gins in Arkansas, Mississippi, Missouri, and Tennessee states, USA. The results suggest that composting CGB may result in more than a 47% increase in fiber and crude protein and at least a 25% decrease in total digestible nutrients and net energy estimations. The differences in macro- and micro-nutrient contents and feed properties suggest that composting CGB may improve the potential for utilization as an animal feed supplement. Establishing the forage properties of CGB is crucial for determining animal feed formulations using CGB as supplements.

The Use of Biologically Converted Agricultural Byproducts in Chicken Nutrition

This article aims to uncover the current knowledge on using bioconverted agricultural byproducts in the chicken diet and the impact of these byproducts on performance, product quality, and health status. Agricultural and agro-industrial activities generate thousands of tons of byproducts. Converting these agricultural byproducts into valuable entities would be an environmentally friendly, sustainable, and viable part of byproduct management. Upon recycling to make new products, the process contributes to socio-economic value and maintaining environmental health and paves the way for realizing energy security and a circular economy. The current paper identifies that solid-state fermentation has attracted more research attention than other fermentation counterparts because it requires minimal moisture, good oxygen availability, cheap media, low wastewater generation, low cost, a low processing scheme, low energy demand, and high productivity. This paper illustrates the role of proteolytic and lignin-degrading enzymes present in bacteria and fungi in the bioconversion process of complex polymers into smaller molecules of amino acids and simple sugar with a profound improvement in the palatability and bioavailability of agricultural products. In addition, the paper gives more detailed insights into using bioconverted agricultural products in chickens to improve performance, product quality, gut microbiota and morphology, and chicken welfare. In conclusion, the bioconversion of agricultural byproducts is an encouraging endeavor that should be supported by governments, research centers, universities, and non-governmental entities to improve the productivity of animal source foods by ensuring environmental sustainability and expanding food security efforts for national development.

Pork organs as a potential source of flavour-related substances

The increase in world population has generated a higher demand for quality proteins, increasing the production in meat industry but also the generation of thousands of tons of by-products, with a negative economic and environmental impact. The valorisation of slaughterhouse by-products by giving by-products a new use as food ingredient is one of the best strategies to add value while reducing environmental damage. Flavour is one of the most influential parameters in the purchasing decision of consumers, and in meat products it is mostly influenced by the content in free amino acids and nucleotides. In this study, the potential of 4 pork organs (liver, kidney, lung, and brain) as a source of flavour-related substances was investigated. Liver proved to be the organ showing the highest content of free and total amino acids related to taste, while kidney was the organ with the highest content of umami nucleotides. The results of the Taste Activity Value indicated that umami, sweet, and bittersweet amino acids are main responsible for the taste of the organs. On the other hand, the synergy between amino acids and nucleotides in relation with umami taste was determined, showing liver and kidney the best values in Equivalent Umami Content. In addition, the antioxidant activity of the organs was determined, and liver and kidney showed the highest antioxidant activity in all assays (p < 0.05). In conclusion, pork organs, especially liver and kidney, may be good candidates to be used as raw materials to produce functional flavouring ingredients.

Green solvents for the selective extraction of bioactive compounds from by-products of the coffee production chain

Approximately 15–20 million tonnes of by-products were generated globally in the coffee production chain during the 2020/21 season. The current uses for these by-products are inadequate or contribute to environmental degradation. This work reports the screening of hydrophilic and hydrophobic solvents, including deep eutectic solvents (DES), for their ability to extract the valuable metabolites caffeine and chlorogenic acid (markers in commercial extraction) from four coffee-related by-products. Water was the best solvent for recovering caffeine and chlorogenic acid from defective green coffee beans, while all hydrophilic DES surpassed water in the extraction of chlorogenic acid from coffee pulp. For the two remaining by-products, at least one DES was as good or better at extracting the caffeine or chlorogenic acid compared to water. The array of hydrophobic solvents tested here showed different selectivities, allowing the annotation of 12 compounds that have not been previously reported in coffee by-products. These results demonstrate the ability to obtain a new and controllable range of extracts from coffee by-products using green and functional solvents.

The Materials Science behind Sustainable Metals and Alloys.

Production of metals stands for 40% of all industrial greenhouse gas emissions, 10% of the global energy consumption, 3.2 billion tonnes of minerals mined, and several billion tonnes of by-products every year. Therefore, metals must become more sustainable. A circular economy model does not work, because market demand exceeds the available scrap currently by about two-thirds. Even under optimal conditions, at least one-third of the metals will also in the future come from primary production, creating huge emissions. Although the influence of metals on global warming has been discussed with respect to mitigation strategies and socio-economic factors, the fundamental materials science to make the metallurgical sector more sustainable has been less addressed. This may be attributed to the fact that the field of sustainable metals describes a global challenge, but not yet a homogeneous research field. However, the sheer magnitude of this challenge and its huge environmental effects, caused by more than 2 billion tonnes of metals produced every year, make its sustainability an essential research topic not only from a technological point of view but also from a basic materials research perspective. Therefore, this paper aims to identify and discuss the most pressing scientific bottleneck questions and key mechanisms, considering metal synthesis from primary (minerals), secondary (scrap), and tertiary (re-mined) sources as well as the energy-intensive downstream processing. Focus is placed on materials science aspects, particularly on those that help reduce CO2 emissions, and less on process engineering or economy. The paper does not describe the devastating influence of metal-related greenhouse gas emissions on climate, but scientific approaches how to solve this problem, through research that can render metallurgy fossil-free. The content is considering only direct measures to metallurgical sustainability (production) and not indirect measures that materials leverage through their properties (strength, weight, longevity, functionality).

Qualitative composition of humus and physical and chemical properties of typical chernozem depending on the fertiliser system

The soil-forming process is closely related to the accumulation and circulation of organic substances, which are a source of nutrients for plants released during the mineralisation of humus, so research on determining the qualitative composition of humus is relevant. In this regard, the purpose of this paper is to determine humic and fulvic acids in typical chernozem, depending on the fertiliser system. The leading approaches to solving this problem are conducting field and laboratory studies to determine the quality indicators of humus and dispersion methods to establish the accuracy and reliability of experimental data. Based on the conducted studies, it was observed that the application of an organo-mineral fertiliser system leads to an increase in the content of humic acids, while the insoluble residue shows an increase in carbon content. The utilisation of organo-mineral fertilisers resulted in a reduction in the excessive accumulation of non-humified organic substances. Additionally, the soils in these areas exhibited a higher level of organic substance humification. The combination of organic matter at a rate of 11.5 tonnes per hectare (8 tonnes of manure and 3.5 tonnes of by-products) and mineral fertilizer N27P38K45 in a crop rotation resulted in an increasing trend of the buffering capacity of typical chernozem soil. In this scenario, there was an increase in absorption capacity at the end of the second rotation for grain-legume crop rotation by 6.05 mg/equiv per 100 g, specialised grain-legume rotation by 3.9 mg/equiv per 100 g, and legume rotation by 3.06 mg/equiv per 100 g of soil compared to the beginning of the first rotation. The use of organo-mineral fertilisers increases the third fraction of fulvic acids in specialised grain-legume rotation, which affects the ratio of humic acids to fulvic acids in favour of the humic type of humus formation. The ratio of humic acids to fulvic acids in the grain-planting crop rotation in the organo-mineral system was 2.84 at the end of the second rotation, and 2.24 at the beginning of the first rotation. The research materials are of practical importance for farmers when analysing the fractional-group composition of typical chernozem humus

Use of distillery by-products asTenebrio molitor mealworm feed supplement

Agricultural and industrial waste represent valuable starting materials to create novel products with economic value added. Winery industry represents an important economic sector in Italy, which produces tons of by-products every year. Global warming and the increasing demand for food and feed led us to analyse the nutraceutical properties of distillery by-products as possible supplements to feedTenebrio molitor larvae (TML). Grape pomace (GP) and grape marcs (GM), grape skin pulp, grape seeds and winery waste sludge were analysed for their antioxidant activity and fatty acid (FA) profile. Even if subjected to multiple processing, by-products had an important content of antioxidant compounds, in particular polyphenols, flavonols, flavonoids and condensed tannins. Moreover, the high amount of polyunsaturated fatty acids and the low percentage of saturated fatty acids found make them useful feed supplements. Herein has been disclosed that their use as TML feed material was well tolerated over TML development, with a significant mean weight gain respect to control of about 25% and no effect on survival rate. Interestingly, total antioxidant activity and FA profile ameliorate significantly, suggesting that distillery by-products can be used to extend the shelf-life of TML and ameliorate their nutraceutical properties, with possible application in controlled dietary regimens. This work confirmed that by-products largely produced in Europe can be used as TML feed materials, simplifying waste management and reducing rearing costs.

Sustainable approaches on industrial food wastes to value-added products – A review on extraction methods, characterizations, and its biomedical applications

The concept of zero waste discharge has been gaining importance in recent years towards attaining a sustainable environment. Fruit processing industries generate millions of tons of byproducts like fruit peels and seeds, and their disposal poses an environmental threat. The concept of extracting value-added bioactive compounds from bio-waste is an excellent opportunity to mitigate environmental issues. To date, significant research has been carried out on the extraction of essential biomolecules, particularly polysaccharides from waste generated by fruit processing industries. In this review article, we aim to summarize the different extraction methodologies, characterization methods, and biomedical applications of polysaccharides extracted from seeds and peels of different fruit sources. The review also focuses on the general scheme of extraction of polysaccharides from fruit waste with special emphasis on various methods used in extraction. Also, the various types of polysaccharides obtained from fruit processing industrial wastes are explained in consonance with the important techniques related to the structural elucidation of polysaccharides obtained from seed and peel waste. The use of seed polysaccharides as pharmaceutical excipients and the application of peel polysaccharides possessing biological activities are also elaborated.

Вплив удобрення та вапнування на баланс і вміст форм калію в дерново-підзолистому ґрунті

Goal. To determine the effect of plant by-products and mineral fertilizers in combination with different doses of dolomite flour on the balance and content of different forms of potassium in soddy podzolic cohesive-sandy soil. Methods. Field (the study of the effect of fertilization and liming on the change in potassium content in the soil), laboratory (the determination of the content of potassium forms in the soil), calculation (the assessment of potassium balance), statistical (the variance analysis of the reliability of research results). Results. The research during 2 rotations of a 4-field crop rotation established that liming 1.9–5.6 tons of dolomite flour with the subsequent annual entering into the soil of an average of 5 tons of by-products of crops in combination with the application of mineral fertilizers at a dose of N112P87K105 per 1 ha of the crop rotation area created the positive balance of potassium in the soil at its intensity of 167–206%. A rapid increase in the content of mobile potassium in the soil in these variants was observed only during the first 4 years of research, in subsequent years it varied within the reached level. Fertilization and liming had a positive effect on the content of all forms of potassium available to plants: water-soluble, exchangeable, and non-exchangeable. During 8 years of research, their content increased by 57.1–121, 40.5–59.5, and 7.8–12.3%, respectively. Conclusions. The use against the background of liming and fertilization of by-products of crop rotation makes it possible to return to the soil 74.0–76.3% of the economic removal of potassium and, in combination with the application of 105 kg/ha of potassium with mineral fertilizers for 1 ha of crop rotation, to create a positive balance of the element at the level of 82.8–88.1 kg/ha. The content of mobile forms of potassium in the soil layer of 0–20 cm in the first 4 years of research in the variants with fertilizer increased from 53–57 to 89–102 mg/kg of soil, in the following 4 years it almost did not increase with certain variations over the years. Under the influence of the studied components of the fertilizer system in crop rotation, the content of all forms of potassium in the soil — water-soluble, exchangeable, and non-exchangeable — increased. Compared to the control, application of N112P87K105 per 1 ha of crop rotation area contributed to an increase in their content by 21.4 and 16.2%, respectively, for a combination of 3.8 t of CaMg(CO3)2 and N112P87K105 — by 57.1–121, 40.5–59.5, and 7.8–12.3%, respectively. However, increasing the dose of dolomite flour from 3.6 to 5.8 t/ha in the crop rotation fertilizer system did not significantly increase the content of non-exchangeable potassium in the 0–20 cm layer of soddy podzolic soil.

Assessment of fish by-products in market environment of Douala and determination of their nutritional value

To assess the fish by-products released, we surveyed 158 fish pre-caterers and 33 structures in 12 markets in Douala. A random sample of these by-products was used for bromatological analysis. Oils extracted from these samples were characterized by determining some chemical indexes. Investigation showed more than 238 tons of by-products are annually released into the environment of the observed markets. Flour Analysis of by-products showed a moisture content of 22.04 ± 0.03%, 50.29 ± 0.02% proteins, 29.03 ± 0.15% ash, 20.3 ± 0.03% lipids, 0.37 ± 0.15% total carbohydrates, and mineral elements such as calcium (6.08 ± 0.002 g / kg), phosphorus (7.093 ± 0.003 g / kg), and iron (328 ± 2.65 mg / kg). Analyses of chemical indexes of the oil extracted showed that they were within the range of Codex Alimentarius standard values. It can be concluded that Douala market’s fish by-products are of good nutritional quality and could therefore be used in animal nutrition.

Bioaccessibility of Bioactive Compounds and Prebiotic Properties of Fruit and Vegetable By-products - A Mini Review

Background: A large proportion of the global production of fruits and vegetables is destined for processing by the food industry. This intense process generates tons of by-products, which may serve as sources of fiber and bioactive compounds, such as polyphenols and carotenoids. Accordingly, numerous studies have investigated the valorization of these by-products focusing on the extraction of bioactive compounds. However, the total amount of bioactive compounds ingested may not reflect the amount available for intestinal absorption, which refers to the bioaccessibility of these compounds. In addition, the interaction of bioactive compounds with dietary fiber and other nutrients may influence their bioaccessibility and may impair the understanding of the physiological effects of these by-products as prebiotic potential. Methods: The purpose of this mini-review is to summarize the main results obtained in the last five years regarding the bioaccessibility of the two major bioactive compounds of fruit and vegetable by-products, i.e., polyphenols and carotenoids, to corroborate the biopotential of this food matrix. Additionally, this review attempts to elucidate the relationship reported between the composition of these by-products and the emerging prebiotic property. Results: In general, the bioaccessibility of polyphenols and carotenoid compounds from fruit and vegetable by-products shows high variability, and it is suggested that the composition of the food matrix is one of the main factors influencing their bioaccessibility. Moreover, a promising prebiotic effect of these by-products is described. Conclusion: The brief literature review with recent studies provide relevant information that may contribute to using the fruit and vegetable by-products as a natural source of bioactive compounds and/ or functional ingredient.

Wealth from by-products: an attempt to synthesize valuable gold nanoparticles from Brassica oleracea var. acephala cv. Galega stems

In the last years, the growth of the world’s population has resulted in an increase in the demand for food. Vegetables and fruit are essential for human nutrition but, regrettably, half the fruit and vegetables produced worldwide are wasted. The food industry generates tons of by-products during processing, for instance, peels, seeds and stems, which still possess bioactive compounds that can be of interest for other applications. The Brassicaceae species includes some of the most consumed vegetables worldwide known for their antioxidant activity associated with the presence of phenolic compounds. In this study, the stems of Brassica oleracea var. acephala cv. Galega (hereafter BG) were employed to prepare an aqueous extract. Then, its antioxidant potential was evaluated by means of the in vitro analysis of its ability to scavenge the free radical 1,1-diphenyl-2-picryl-hydrazyl (DPPH), the quantification of the total phenolic content and the analysis of the reducing power. Furthermore, the stem aqueous extract was employed to produce gold nanoparticles (AuNPs), acting as a reducing and stabilizing agent. AuNPs were characterized by UV–Visible and Fourier transform infrared spectroscopy. The size and shape of the nanoparticles was analyzed by the acquisition of transmission electron microscopy images, confirming the formation of spherical AuNPs with mean diameters of 25.08 ± 3.73 nm. Finally, three antioxidant assays were performed in the extract after the synthesis of AuNPs. The synthesis of AuNPs employing BG stem extract was revealed to be a good alternative for the revalorization of Brassica by-products.

A facile green reduction of graphene oxide using Terminalia Catappa leaves extract, it’s anti-microbial properties and adsorption behavior of food wastes

Food processing factories produce tonnes of by-products mainly includes polyphenols and foodprocessing wastewater which have several advantages like antimicrobial applications and UV protectingphenomena that can be utilized as nutraceuticals and these valuable by-products can be recovered tominimize solid waste disposal. In this study, we have discussed the eco-friendly reduction of grapheneoxide (GO) to reduced graphene oxide (rGO) using Terminalia catappa (TC) leaves extract. Thesynthesized reduced graphene oxide is characterized by Fourier transform Infra-red Spectroscopy (FTIR), UV Spectroscopy (UV), Thermogravimetric analysis (TGA), X-ray diffraction (XRD), 3D opticalprofilometer, Scanning Electron Microscope (SEM) and Elemental analysis (EDAX). Further Antimicrobial properties of the produced reduced graphene oxide are investigated. To summarize, assynthesized facile reduced graphene oxide can be employed as a low-cost adsorbent for by-products fromfood industries.

Environmental impact assessment of cement industries using mathematical matrix method: case of Ghayen cement, South Khorasan, Iran.

Cement industries produce millions of tons of by-products each year, including dust, toxic gases, and heavy metals, which pose respiratory health hazards and environmental pollution. Although several literatures have investigated environmental impact in cement factories, the extent to which these assessments affect the population has received limited responsiveness. This study investigates this gap by examining the environmental impacts of the Ghayen Cement Industry on environmental components and public health. Using a mathematical matrix, it found that the effect of the cement factory on the environment produced four categories of significant effects: L, low; M, medium; H, high; and VH, very high. Results in terms of basic criteria revealed 0.70 of the most destructive effect was related to water pollution. Regarding the interaction effect of project activities (basic and complimentary basic criteria) on environmental components, the highest destructive effect was excavation and land deformation while the lowest effect was on public health. The study also found out that the use of compensation factors reduced the negative effect of the project on the environment. The use of common methods of environmental improvement such as erosion control, proper location of facilities, and the creation of green spaces is essential to mitigate the impact of projects on the environment.

Sustainable Development of Surplus By-Products of the Agri-Food Chain with the Purpose of Reducing Environmental Damage

The global food industry annually generates millions of tons of by-products derived from the processing and manufacturing of citrus fruits. Only a small part is used to obtain new products and the rest is considered as waste, with the consequent negative impact on the environment. The purpose of this research work is to use the products extracted from citrus fruits of orange, grapefruit, tangerine and lemon, being used in the diet of ruminants as a source of energy, supplement or alternative in the face of a shortage of forage. Making the use of these by-products in order to reduce the environmental impact of the waste generated.

Barriers, drivers, and relationships in industrial symbiosis of a network of Brazilian manufacturing companies

The purpose of this article is to identify barriers, drivers, and the structure of the relationships that support industrial symbiosis initiatives in a network of Brazilian manufacturing companies. Two steelmaking plants are the anchor tenants of the network comprising a cement manufacturer, a thermoelectric generation plant, a lead ingots manufacturer, a zinc ingots manufacturer and refractory liner manufacturer, totaling eight relationships. The companies mutually exchange approximately 300,000 tons of by-products per year, comprising coal ash, mill scale, electric arc furnace dust, steam, zinc sludge, lead sludge, and refractory lining leftover, totaling eight dyadic or triadic relationships. The results of the study show that in three relationships, economic barriers exist (excessive processing or logistic cost). In four, internal barriers exist (risk of discontinuity and lack of research). In five, a technical barrier exists, the imbalance between generation and consumption. In seven, the drivers are cost reduction, new products or sources of revenue, and legal requirements. Environmental drivers (increasing the life of deposits or landfills) are present in five relationships. As for the structure, three relationships are one-way, whereas five are closed-loop, that is, involving direct and reverse transfers among partners.