Agro-industrial Residues Research Articles

Nutrient Removal from Aqueous Solutions Using Biosorbents Derived from Rice and Corn Husk Residues: A Systematic Review from the Environmental Management Perspective

This review critically analyzed the use of biosorbents derived from rice husks and corn residues for nutrient removal from aqueous solutions. Additionally, this review highlighted the use of such biosorbents in wastewater treatment. Furthermore, novel approaches for sustainable nutrient removal from aqueous solutions were identified. A comprehensive understanding of the implementation of biosorption processes using agro-industrial residues based on corn and rice crops is critical for the sustainable management of residues and water bodies in the world to protect and conserve natural resources. Specifically, the review focuses on the exploration, preparation and application of innovative biosorbents to remove various forms of nutrients such as total nitrogen, total phosphorus, nitrates, ammonium and phosphates from aqueous solution, analyzing the sustainability of treatments applied to biomass, such as thermal transformation or chemical modification to reduce environmental impacts. It was found that 95 to 99% of nitrogen and phosphorus can be removed with biosorbents made from rice husks and corn residues, analyzing approximately 50 scientific articles related to these plant materials. Research opportunities were identified, such as the recovery of removed nutrients for soil improvement, life cycle analysis to assess the concept of zero waste, among other aspects. Finally, a scheme is proposed for the selection and application of sustainable biosorbents for the removal of nutrients from aqueous solutions.

Production of Gibberellic Acid by Aspergillus Niger: A Review

Gibberellic acid (GA3) is a plant hormone found naturally in plants and fungi. It is a white to pale-yellow solid with the chemical formula C19H22O6. Although plants naturally produce GA3, it is often produced commercially from fungi for agricultural use. The production of GA3 through fermentation methods, including submerged fermentation (SmF) and semi-solid-state fermentation (SSSF), is explored, with a focus on optimizing production and reducing costs. Additionally, the review delves into the factors influencing GA3 production, both physical and chemical parameters. It emphasizes the use of agro-industrial residues as cost-effective sources for GA3 production, promoting environmentally friendly recycling and reducing the environmental impact. Quantification methods for GA3, are discussed, highlighting the challenges and benefits associated with each method. Furthermore, the applications of GA3 in horticulture, agriculture, and the food industry are outlined, demonstrating its diverse range of effects on various plants and crops.

Uncovering the lignin-degrading potential of Serratia quinivorans AORB19: insights from genomic analyses and alkaline lignin degradation

BackgroundLignin is an intricate phenolic polymer found in plant cell walls that has tremendous potential for being converted into value-added products with the possibility of significantly increasing the economics of bio-refineries. Although lignin in nature is bio-degradable, its biocatalytic conversion is challenging due to its stable complex structure and recalcitrance. In this context, an understanding of strain's genomics, enzymes, and degradation pathways can provide a solution for breaking down lignin to unlock the full potential of lignin as a dominant valuable bioresource. A gammaproteobacterial strain AORB19 has been isolated previously from decomposed wood based on its high laccase production. This work then focused on the detailed genomic and functional characterization of this strain based on whole genome sequencing, the identification of lignin degradation products, and the strain’s laccase production capabilities on various agro-industrial residues.ResultsLignin degrading bacterial strain AORB19 was identified as Serratia quinivorans based on whole genome sequencing and core genome phylogeny. The strain comprised a total of 123 annotated CAZyme genes, including ten cellulases, four hemicellulases, five predicted carbohydrate esterase genes, and eight lignin-degrading enzyme genes. Strain AORB19 was also found to possess genes associated with metabolic pathways such as the β-ketoadipate, gentisate, anthranilate, homogentisic, and phenylacetate CoA pathways. LC–UV analysis demonstrated the presence of p-hydroxybenzaldehyde and vanillin in the culture media which constitutes potent biosignatures indicating the strain’s capability to degrade lignin. Finally, the study evaluated the laccase production of Serratia AORB19 grown with various industrial raw materials, with the highest activity detected on flax seed meal (257.71 U/L), followed by pea hull (230.11 U/L), canola meal (209.56 U/L), okara (187.67 U/L), and barley malt sprouts (169.27 U/L).ConclusionsThe whole genome analysis of Serratia quinivorans AORB19, elucidated a repertoire of genes, pathways and enzymes vital for lignin degradation that widens the understanding of ligninolytic metabolism among bacterial lignin degraders. The LC-UV analysis of the lignin degradation products coupled with the ability of S. quinivorans AORB19 to produce laccase on diverse agro-industrial residues underscores its versatility and its potential to contribute to the economic viability of bio-refineries.

FIBRE EFFECTS ON NUTRITION AND REPRODUCTION IN PIGS

Dietary fibre (DF) is an indigestible carbohydrate in the form of a non-starch polysaccharide that is a major problem in the use of inexpensive agro-wastes by pigs such as brewer's dry grains, cassava peel, palm kernel cake, rice bran, sorghum spent grain and wheat offal. The DF in a pig's diet can be classified by its solubility as soluble dietary fibre and insoluble dietary fibre, and chemically − as neutral detergent fibre and acid detergent fibre. High DF levels reduced nutrient utilization, growth rate, in terms of pork production and reproductive performance. Pigs' reproductive cycles at different stages and lactation were both greatly impacted by increased DF intake. High DF decreased the number of stillborn piglets at birth and the farrowing duration by sow, while improving colostrum intake in piglets and colostrum yield in sows. On the other hand, reducing the quantity of DF's hemicellulose in a sow's lactation diet can improve the low-birth-weight piglets' health, post-weaning performance and milk composition. While exogenous enzymes and the extrusion of fibrous feedstuffs enhanced nutrient digestibility and utilisation, other processing methods, including fermentation and extrusion, decreased the DF components and had a beneficial impact on the performance of the pigs. Agro-industrial residues have enormous potential to improve reproductive efficiency and serving as an economically viable DF feeding strategy in the pig industry.

Fractional and Chemical Characterization of Green Coconut Fiber Bio-Oil Using Fast-GC×GC/TOFMS

Brazil is renowned for its expertise in utilizing biomass for energy and biomaterials. Notably, in tandem with biomass processing, the country has a high potential for bio-products derived from agro-industrial residues, such as green coconut fibers. This study focused on using green coconut fibers in bio-oil production via pyrolysis (at 700 ºC with a heating rate of 100ºC/min). The bio-oil underwent fractionation using preparative liquid chromatography on silica (PLC) with solvents of varying polarities. The fractions of bio-oil were then analyzed using fast-GC×GC/TOFMS. This analytical technique significantly reduced the analysis time to 15 minutes per sample. The predominant compounds identified included phenols, furfural derivatives, and hydrocarbons, underscoring the bio-oil's potential for industrial applications.

The influence of dietary supplementation with fermented agro-industrial residue of faba bean on Japanese quail performance, immunity, gut microbiota, blood chemistry, and antioxidant status

Antibiotic overuse in poultry feeds has disastrous implications; consequently, long-term alternatives must be developed. As a result, the current study aims to assess the impact of Aspergillus niger filtrate (ANF) high in organic acids grown on agro-industrial residue of faba bean (AIRFB) on quail diet, as well as their influence on bird productivity, digestion, carcass yield, blood chemistry, and intestinal microbiota. A total of 240 Japanese quails (aged 7 d) were used in this study, divided equally among 5 experimental groups with 48 quails each. Group 1 (G1) received a basal diet without any ANF, group 2 (G2) received a basal diet supplemented with 0.5 mL ANF/kg diet, group 3 (G3) received a basal diet supplemented with 1.0 mL ANF/kg diet, group 4 (G4) received a basal diet supplemented with 1.5 mL ANF/kg diet, and group 5 (G5) received a basal diet supplemented with 2 mL ANF/kg diet. The performance parameters were monitored at 1 to 3, 3 to 5, and 1 to 5 wk. Adding ANF increased body weight at 3 and 5 wk, as well as body weight gain at 1 to 3, 3 to 5, and 1 to 5 wk, compared to the control diet. The ANF fed quails had the highest feed conversion ratio compared to the control group. The addition of ANF to the quail diet had no effect on the weight of the carcass, gizzard, heart, liver, giblets, or dressing; however, it did lower triglycerides, low-density lipoprotein, and very low-density lipoprotein while increasing high-density lipoprotein levels. The quail groups that received ANF had enhanced immunological indices such as IgG, IgM, IgA, and lysozymes. It also increased the levels of superoxide dismutase and total antioxidant contents, as well as catalase, and digestive enzymes such as protease, amylase, and lipase. However, it lowered the blood MDA levels compared to control. It has been demonstrated that the total gut microbiota, Escherichia coli, total coliforms, and the population of Salmonella are all reduced in ANF-fed quails. Histological examination of ANF quails' liver and intestinal sections revealed normal hepatic parenchyma, typical leaf-like intestinal villi, and comparatively short and frequently free lumina. In conclusion, Japanese quail showed improvements in performance, digestive enzymes, antioxidant indices, immunity, and capacity to reduce intestinal pathogenic bacteria after consuming diet supplemented with ANF.

Mixotrophic cultivation of microalgae using agro-industrial waste: Tolerance level, scale up, perspectives and future use of biomass

Alternative culture media make large-scale microalgae biomass production more viable and cost-effective. The aim of this work was to study the addition of whey as an alternative source of organic nutrients in fed-batch mode for the cultivation of microalgae (Spirulina platensis, Chlorella homosphaera and Scenedesmus obliquus). The microalgae demonstrated acceptance of whey at low concentrations, causing the increasing in the maximum specific growth rates (μmax) and biomass concentrations ([X]max) compared with the cultivation without whey in standard medium (μmax of 0.168 d−1 versus 0.075 d−1, and [X]max of 2.274 g L−1 versus 0.970 g L−1, respectively, for S. platensis). Therefore, a cost savings in cultivation media of up to 32 %, 57 %, and 73 % were possible in the cultivation of S. obliquus, S. platensis, and C. homosphaera, respectively, considering the production of 1 kg of biomass. The addition of whey presented different effects in the levels of intracellular protein considering the species of microalgae: an increasing was observed in C. homosphaera (24.18 to 43.96 g/100 g of biomass) and a decreasing in S. platensis (73.75 to 44.06 g/100 g of biomass), comparing with the controls. Scale-up with a natural light source can affect microalgal productivity and biomass composition in a medium supplemented with whey, because of the influence of irradiation. Optimizing the large-scale production of microalgae using agro-industrial residues can lead to significant advancements in biomass production at reduced costs. These biomasses can be integrated into bioenergy production, biofertilizer manufacturing, and animal feed production. By utilizing waste as a nutritional source and optimizing cultivation processes and biomass generation, a closed-loop cycle is established, aligning with the principles of circular bioeconomy and enhancing the sustainability of the process.

Bioenergy and Biorefinery Potential of Residues: A Representative Case of the Sucre Region in Colombia

AbstractAgricultural and agroindustrial residues are produced worldwide but these residues do not have a specific use. Then, a high potential to produce bioenergy and value-added products has been wasted. Biomass conversion routes should be proposed based on regional needs, making different upgrading processes more reliable and feasible. Thus, bioenergy applications should be analyzed as potential solutions before analyzing prospective products based on the biomass chemical composition. The objective of this research is to provide an approach for defining potential energy-driven applications of lignocellulosic biomass in developing countries with high availability of biomass sources as a result of the agricultural vocation of a region/country. As a case study, this paper shows the Sucre region in Colombia. A methodological approach to define thermochemical, anaerobic digestion, and biorefining upgrading pathways is provided based on chemical characterization, proximate analysis, fuel properties, and biogas production potential. Corn cobs, rice husk, cassava stem, and subverified cassava stem were the most suitable feedstocks for thermochemical upgrading. Avocado seeds, peels, and cassava leaves were selected as the most suitable raw materials for biogas production. Finally, plantain peel, rachis, and organic food waste were selected as potential and prospective raw materials in biorefinery systems to produce high-value-added products. Graphical Abstract

Enhancing Xylanase Production from Aspergillus tamarii Kita and Its Application in the Bioconversion of Agro-Industrial Residues into Fermentable Sugars Using Factorial Design

The endo-1,4-β-xylanases (EC 3.2.1.8) are the largest group of hydrolytic enzymes that degrade xylan, the major component of hemicelluloses, by catalyzing the hydrolysis of glycosidic bonds β-1,4 in this polymer, releasing xylooligosaccharides of different sizes. Xylanases have considerable potential in producing bread, animal feed, food, beverages, xylitol, and bioethanol. The fungus Aspergillus tamarii Kita produced xylanases in Adams’ media supplemented with barley bagasse (brewer’s spent grains), a by-product from brewery industries. The culture extract exhibited two xylanase activities in the zymogram, identified by mass spectrometry as glycosyl hydrolase (GH) families 10 and 11 (GH 10 and GH 11). The central composite design (CCD) showed excellent predictive capacity for xylanase production (23.083 U mL−1). Additionally, other enzyme activities took place during the submerged fermentation. Moreover, enzymatic saccharification based on a mixture design (MD) of three different lignocellulosic residues was helpful in the production of fermentable sugars by the A. tamarii Kita crude extract.

The Value of Indigenous <i>Saccharomyces cerevisiae</i> Strains as Useful Enzymes Producers: A Systematic Review

This systematic review has focused on the selection and characterization of indigenous Saccharomyces cerevisiae strains for enzymes' production obtained from the fermentation process. The primary studies assessed have demonstrated that indigenous S. cerevisiae strains produce a wide range of enzymes during fermentation. These strains have shown different characteristics and were isolated from various locations, including those belonging to the main components of the wine production chain. The research methodology applied to find primary studies about the optimal conditions for enzyme production was effective and identified a wide range of enzyme classes. Cultivation media amended with natural or synthetic inducer substrates were found to be suitable carbon and/or nitrogen sources for producing enzymes of interest in plate-based screening. In submerged fermentation studies, the use of agro-industrial residues has been identified as a relevant carbon source for microbe development and metabolism. For the indigenous S. cerevisiae strains, the majority of the enzymes found belong to the glucosidases and hydrolases classes. Due to the activity of these enzymes, yeasts have been traditionally used in classic biotechnological applications, particularly in the process of alcoholic fermentations. Those enzymes are responsible for producing metabolites (such as aromatic compounds) that contribute to the desirable aroma and/or taste during the fermentation of wine, as well as other fermented or distilled beverages. The methods used for enzyme screening were of quantitative and/or qualitative nature and were carried out under acidic pH conditions (3.5-6.5) and at temperatures of 28-35 ℃. The results of this systematic review have shown that the enzymes from indigenous S. cerevisiae are highly relevant in various biotechnological applications, particularly in the food industry. Conclusions and future perspectives of our findings were discussed in terms of potential developments of novel application methods of the indigenous yeasts and their enzymes in agriculture and industry.

Biochemical, functional and antioxidant potential of higher fungi cultivated on agro-industrial residues. Part II: Cultures on mixtures of spent mushroom substrates and mushroom cropping by-products

Novel substrates consisted of different fresh agro-industrial residues, their corresponding and commercial spent mushroom substrates (i.e. SMS deriving from laboratory-scale experiments and SMS deriving from industrial-scale experiments by Green Zin S.A. - SMS GZ) and Pleurotus waste (PW; stipes/mishappen mushrooms) were used in blends for a new cultivation cycle of Pleurotus ostreatus and P. eryngii mushrooms in bags. Their impact on the biochemical properties (intra-cellular polysaccharides - IPSs, protein, lipid, total phenolic compounds - TPCs, individual carbohydrates composition of the IPSs) in the first- and second-flush whole mushrooms, pilei and stipes, as well as the fatty acids composition, the antioxidant activity (in the first-flush mushroom parts) and glucan content of stipes were examined. Both species produced satisfactory IPSs quantities in all substrates (28.69–46.38 %, w/w) and significant protein amounts (18.37–26.80 %, w/w). The further SMS addition (80 %, w/w instead of 40 %, w/w) in the cultivation substrates affected positively the mushroom IPSs values, whereas the highest protein content was detected in mushroom's parts cultivated on substrates consisted of fresh agro-industrial residues. Mushroom's lipid content was affected differently by the various substrate combinations, with SMS presence resulting in mushrooms with a lower fat content than those produced in substrates with PW addition. Fresh substrates with PW and those with coffee residue were the most favorable for TPCs production. Regarding production flushes, the nutritional value of mushrooms was comparable between them, only a slight increase in TPCs of second-flush carposomes was detected. Glucose was the predominant monosaccharide of the produced IPSs, combined with a significant production of total and β- glucans. SMSs and PW addition had a positive impact on antioxidant activity, too. A higher quantity of lipids, TPCs and significant antioxidant activity were detected in all Pleurotus pilei than stipes, whereas the latter were richer in IPSs. Both pilei and stipes had a significant protein amount. Hence, the data obtained by this study support the positive effect of different types of SMS and mushroom waste on P. ostreatus and P. eryngii nutritional value.

Bioinformatics for circular economy research decision-making: A case study in obtaining bioactive peptides from Citrus sinensis peels via limonene synthase analysis

In the era of technology-driven research, bioinformatics is crucial for informed decision-making. Extracting orange essential oil, a key source of Limonene, offers a valuable opportunity. While Limonene extraction is established, potential compounds in orange peel waste can create additional value-added products. Bioactive peptides extracted from this waste can be transformed into high-value products. Limonene synthase exemplifies how bioinformatics aids strategic planning for agro-industrial residue reuse. The sequence of Limonene synthase (Chain A), derived from Citrus sinensis, was analyzed in silico, using BIOPEP, PeptideRanker, ToxinPred, CSM-Toxin, PepDraw, and iBitter-SCM. In the protein sequence profiles, the peptides are non-toxic and possess a bitter taste. The frequency of occurrence of biologically active fragments in protein sequences showed high values for dipeptidyl peptidase IV inhibitor (A = 0.5822) and ACE inhibitor (A = 0.3665). The simulation of theoretical enzymatic hydrolysis (conducted using the BIOPEP-UWM database) is a good approach to discern the selection of proteins with greater potential for high-value applications; pepsin (pH > 2) was the better option in this case. The biorefinery concept can be optimized by utilizing bioinformatics tools, aligning with Sustainable Development Goals, and efficient waste management. In silico analysis showed that inhibitory peptides of natural origin derived from Limonene synthase are health-promoting substances and can potentially be used against diseases such as Diabetes mellitus and hypertension, among others. These bioactive peptides have high added value, and recycling them contributes to transitioning from a linear economy to a circular economy.

Two-domain GH30 xylanase from human gut microbiota as a tool for enzymatic production of xylooligosaccharides: Crystallographic structure and a synergy with GH11 xylosidase

Production of value-added compounds and sustainable materials from agro-industrial residues is essential for better waste management and building of circular economy. This includes valorization of hemicellulosic fraction of plant biomass, the second most abundant biopolymer from plant cell walls, aiming to produce prebiotic oligosaccharides, widely explored in food and feed industries. In this work, we conducted biochemical and biophysical characterization of a prokaryotic two-domain R. champanellensis xylanase from glycoside hydrolase (GH) family 30 (RcXyn30A), and evaluated its applicability for XOS production from glucuronoxylan in combination with two endo-xylanases from GH10 and GH11 families and a GH11 xylobiohydrolase. RcXyn30A liberates mainly long monoglucuronylated xylooligosaccharides and is inefficient in cleaving unbranched oligosaccharides. Crystallographic structure of RcXyn30A catalytic domain was solved and refined to 1.37 Å resolution. Structural analysis of the catalytic domain releveled that its high affinity for glucuronic acid substituted xylan is due to the coordination of the substrate decoration by several hydrogen bonds and ionic interactions in the subsite −2. Furthermore, the protein has a larger β5-α5 loop as compared to other GH30 xylanases, which might be crucial for creating an additional aglycone subsite (+3) of the catalytic site. Finally, RcXyn30A activity is synergic to that of GH11 xylobiohydrolase.

Coconut Waste: Discovering Sustainable Approaches to Advance a Circular Economy

The coconut tree (Cocos nucifera) stands as a pivotal resource in tropical regions, playing a crucial role in both subsistence and economic activities across Asia, the Pacific Islands, and South America. While the harvesting of coconut fruit is essential for producing globally utilized edible products, such as coconut oil, by small owners and large producers around the world in the food, cosmetics, and pharmaceutical industries, concerns have arisen due to the substantial amount of agro-industrial residue generated in this process, posing environmental risks if they are not properly managed. Recognizing the environmental challenges, this paper emphasizes the transformative potential inherent in coconut waste, characterized by its lignocellulosic composition rich in lignin and multifunctional groups. By delving into the historical context of coconut economic exploration and its chemical composition, this review explores the diverse applications of coconut products, focusing on the utilization and processing of residues to generate sustainable products and byproducts. Ultimately, this comprehensive review underscores the significance of repurposing coconut waste, not only to mitigate the environmental impact but also as a valuable contributor to a circular economy, promoting the use of the lignocellulosic biomass in research and bolstering its role as a raw material in the chemical and energy sectors.

High Added-Value by-Products from Biomass: A Case Study Unveiling Opportunities for Strengthening the Agroindustry Value Chain

The current era witnesses a remarkable advancement in biomass utilization, guided by the principles of green chemistry and biorefinery and the comprehensive exploitation of plant-based raw materials. Predominantly, large-scale production methods have been pursued, akin to approaches in the oil industry, enabling the incorporation of novel products into energy and petrochemical markets. However, the viability of such systems on a small and medium scale is hindered by logistical challenges and the constraints of economies of scale. For small agricultural producers and food processing companies, the complete utilization of biomass transcends environmental responsibility, evolving into a strategy for survival through the diversification of by-products with enhanced value. The state of Rio de Janeiro in Brazil presents a range of population dynamics, geographical features, climate conditions, and agricultural production patterns that closely resemble those found in various tropical countries and agricultural regions worldwide. This region, sustaining a green belt supporting 17 million people, provides an apt case study for investigating chemical compounds with potential value among agro-industrial residues, which can motivate the creation of a lucrative biotechnological industry. Examples include naringenin and hesperidin from oranges and lemons, epi-gallo-catechin gallate from bananas, caffeic acids from coffee, and the bromelain enzyme from pineapples. This study addresses the challenges associated with developing biotechnological alternatives within the agroindustry, considering economic, technological, logistical, and market-related aspects. The insights from examining the Brazilian state of Rio de Janeiro will contribute to the broader discourse on sustainable biomass utilization and the creation of value-added by-products.

Production of asparaginase from Bacillus licheniformis using agro-industrial residues as carbon and nitrogen sources

درست جدوى استخدام عدد من المخلفات الزراعية- الصناعية كركائز لإنتاج إنزيم الأسبارجيناز من بكتيريا Bacillus licheniformis المعزولة من التربة المحلية، حيث استخدمت المخلفات الغنية بالغلوكوز كمصدر للكربون (قشور العنب، قشور التفاح، قشور الجزر، قشور البطاطا، مخلفات الذرة، مخلفات عصر قصب السكر، قشور الموز)، وأضيفت إلى وسط التخمير بتراكيز مختلفة (1، 1.5، 2، 2.5، 3%). كما استخدمت المخلفات الغنية بالنيتروجين (كسبة فول الصويا، قشور الفول، ماء الحمص المسلوق، الشرش) وفق التراكيز 1، 2، 3، 4، 5%. استخدمت طريقة المزارع المغمورة لإنتاج الأنزيم، وقُدِّرت الفعالية الأنزيمية للأنزيم المُنتَج لتحديد التركيب الأمثل لوسط التخمير. وقد أظهرت النتائج تفوق قشور العنب (بنسبة إضافة 3%) كمصدر للكربون، وكسبة فول الصويا (بنسبة إضافة 5%) كمصدر للنيتروجين بالمقارنة مع المخلفات النباتية الأخرى. وقد بلغت فعالية الأنزيم المنتج بالتخمير باستخدام الوسط وفق التركيب آنف الذكر 2595.30 ميكرومول/مل كما بلغت الفعالية النوعية للأنزيم 1089.1 وحدة/مغ.

Application of Corn Straw, an Agro-Waste, to Remove Dyes in an Aqueous Medium, Producing Blue or Red Fibers

The contaminant dyes that, even at low concentrations, may cause a series of adverse effects in humans and animals, and their removal by adsorption methods using alternative adsorbents as natural fibers, are regarded as a research topic that has become increasingly relevant. In this study, corn straw (CS), an agro-industrial residue, was used to remove dyes. The samples were characterized by ATR-FTIR, SEM-EDS, zeta potential, diffuse spectra, and colorimetry, before and after dye removal. The analyses allowed us to differentiate the morphology of CS after the treatment’s fiber on the adsorbent surface. The zeta potential showed a negative surface charge, but the acidic or alkaline treatment affected the surface charge of the sample, influencing the adsorption of cationic or anionic dyes. Adsorption data presented an increased removal when alkaline treatment was applied for the methylene blue (MB; qmax = 16.7 mg g−1), and the acid treatment was more effective for the Congo red (CR; qmax = 2.13 mg g−1). After color stability tests, it was observed that the anionic dye CR was more easily desorbed due to the surface charge of the adsorbent. Due to the chemical treatment, corn straw proved to be a good sustainable adsorbent for removing anionic or cationic dyes from aqueous media, contributing directly to the objective of sustainable development (#6—drinking water and sanitation) and with SDG numbers 3, 11, 12, 14, and 17.

Polypropylene Composites Reinforced with Lignocellulose Nanocrystals of Corncob: Thermal and Mechanical Properties

Composites based on recycled polypropylene (PP) reinforced with cellulose nanocrystals whit lignin corncob were prepared. The effect of the ratio composites prepared via a compression molding process on the mechanical and thermal properties was analyzed. Corncobs is a little-used agroindustrial residue with a high cellulose content. The corncob was milled and then delignified via the organosolve process in order to get the cellulose unbleached. An acid hydrolysis process was then carried out to obtain lignocellulose nanocrystals (LCNCs). Subsequently, LCNC/PP composites were obtained via termocompression molding using different concentrations of LCNC (0, 0.5, 1 and 2% by weight) previously mixed via extrusion. The residual lignin present in the LCNCs improved the compatibility between the reinforcement and the PP matrix. This was evidenced by the increase in mechanical properties and the stabilization of thermal properties. The results of the mechanical tests showed that the LCNC increases the tensile and flexural modules and strength with respect to neat PP. Composites with 2% of LCNC showed an increase of 36% and 43% in modulus and tensile strength, respectively, while the flexural modulus and strength increased by 7.6%. By using reinforcements of natural and residual origin (corncob) and improving the properties of recycled polymers, their reuse will increase, and this can lead to reducing waste in the environment.

PHYSICAL AND CHEMICAL PROPERTIES OF SUBSTRATE DERIVED FROM COFFEE RESIDUE FOR SEEDLING PRODUCTION

The physical-chemical properties of substrates based on coffee residues for seedling production were analyzed. The production of seedlings is associated with the quality of the substrates used. The characterization of the physical-chemical properties is a fundamental part of components and their proportions in formulating substrate selection. Thus, the objective of this work was to analyze the physical-chemical properties of components and formulations based on agro-industrial residues. The quality of the use of three components, fresh coffee straw, carbonized coffee straw, and composted coffee straw, in 25 different formulations of substrates for seedling production were evaluated. The dry density, current humidity, total porosity, aeration space, easily available water, water retention capacity, electrical conductivity, and pH were evaluated. The experiment followed a completely randomized design with three replications, and the data obtained were analyzed by ANOVA and the Scott-Knott test (p<0.05). All substrates had statistical differences among themselves, for all variables studied. Coffee processing residue presented physical and limited electrical conductivity and pH characteristics. Formulated products have physical and chemical characteristics depending on their constituents and proportions. Three substrates stood out for presenting good chemical and physical characteristics, which were based on 30-40% carbonized or composted coffee straw. The results obtained here will work as an important tool to guide decision-making regarding the constituents and adequate proportions in formulating substrates for seedling production

Life cycle carbon analysis of packaging products containing nonwood residues: A case study on linerboard and corrugating medium

Circularity is creating momentum toward utilizing waste feedstock in a myriad of applications. The paper industry is not an exception to this trend, and packaging products made from agricultural or agro-industrial residues are receiving more attention now than ever. Additionally, negative consumer perceptions of tree felling are accelerating the acceptance of these fibers. Nevertheless, adopting these residues raises the issue of whether they constitute a better alternative to fight climate change than wood. Answering this question is imperative to ensure that pledges to reduce carbon footprints across the industry are fulfilled. This paper aims to estimate the carbon footprint of corrugating medium and linerboard containing wheat straw and sugarcane bagasse pulp compared to analogous wood-based materials. The goal was also to understand how methodological decisions to allocate emissions to nonwood residues can affect the results. This study includes a life cycle carbon analysis spanning from cradle to grave, which comprises stages for residue production, pulping, paper-making, waste management, and corresponding transportation. For the proposed case study, the results suggest that straw- and bagasse-based medium and linerboard can present a higher carbon footprint than products made from virgin and recycled wood fibers. The main driver is the production of nonwood chemimechanical pulp. In addition, the lower capacity of nonwood residues to be recycled increases the overall impact. Finally, decisions around emissions allocation highly influence the results. This study helps mitigate part of the uncertainty around the environmental sustainability of corrugating medium and linerboard made from the selected nonwood residues.