Search Results (99)

Traditional stabilization techniques, such as lime and cement, widely used for their effectiveness, albeit with economic and environmental limitations, are leading to the search for sustainable approaches that utilize agricultural and industrial waste, such as rice husk ash, bagasse, and natural fibers. These have been shown to improve key geotechnical properties, even under saturated conditions, significantly. In particular, the combination of rice husk ash and recycled ceramics has shown notable results in Ecuadorian coastal soils. The article emphasizes the importance of selecting techniques that balance effectiveness, cost, and sustainability and identifies existing limitations, such as the lack of long-term data (ten years) and predictive models adapted to the Ecuadorian climate. From a bibliographic perspective, this article analyzes the challenges posed by expansive soils in the western coastal region of Ecuador, whose high plasticity and instability to moisture negatively affect civil works such as roads and buildings. The Ecuadorian clay contained 30% kaolinite and only 1.73% CaO, limiting its chemical reactivity compared to soils such as Saudi Arabia, which contained 34.7% montmorillonite and 9.31% CaO. Natural fibers such as jute, with 85% cellulose, improved the soil’s mechanical strength, increasing the UCS by up to 130%. Rice husk ash (97.69% SiO₂) and sugarcane bagasse improved the CBR by 90%, highlighting their potential as sustainable stabilizers. All of this is contextualized within Ecuador’s geoenvironmental conditions, which are influenced by climatic phenomena such as El Niño and La Niña, as well as global warming. Finally, it is proposed to promote multidisciplinary research that fosters more efficient and environmentally responsible solutions for stabilizing expansive soils. Full article

The extensive accumulation of plastic waste causes serious environmental problems, leading to growing interest in biodegradable alternatives. In this study, the structural, chemical, and crystalline characteristics of a pulp-based material incorporating sugarcane bagasse ash (SCBA) were investigated using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). Mechanical properties of the materials were investigated through compression, tensile, and bending tests in order to assess their strength and flexibility, while biodegradability was evaluated through soil burial tests. The results indicate that SCBA addition enhances compressive strength, with optimal performance obtained at 15% SCBA content, while tensile and bending strengths showed an enhancement at 5% content. FTIR and XRD analyses suggested an increase in amorphous regions and notable microstructural interactions between SCBA particles and cellulose fibers, particularly at a 10% concentration. SEM images further confirmed effective particle dispersion and improved porosity in the composite materials. Furthermore, samples incorporating SCBA exhibited superior biodegradability compared to pure pulp. Overall, these findings highlight that incorporating 10–15% SCBA provides a promising balance between mechanical integrity and environmental sustainability, offering a viable strategy for developing eco-friendly, high-performance packaging materials. Full article

Sugarcane bagasse (SCB), an organic waste generated during sugar and ethanol production, is a potential biomass source with a high cellulose content. In this study, cellulose was extracted from SCB using a hydrothermal method with various types of solvents, following which the extracted materials were used for food container production. An alkali solvent—sodium hydroxide (NaOH)—and organic acids—citric acid and formic acid—were included as extractive solvents at two different concentrations (0.25 M and 2.0 M). Hydrothermal extraction with the alkali solvent demonstrated higher cellulose extraction abilities (67.7–74.0%) than those with the acids (52.5–57.3%). Using a low alkali concentration in the hydrothermal extraction (H-NaOH_low) demonstrated a cellulose extraction ability near that when using a high alkali concentration in the conventional boiling method (B-NaOH_high): 67.7% and 70.5%, respectively. Moreover, cellulose extracted with H-NaOH_low had better mechanical properties than that from B-NaOH_high, likely due to fewer defective fibers in the former. A high alkali concentration led to vigorous reactions that damaged the cellulose fibers. Thus, hydrothermal extraction has the benefit of using fewer chemicals, leading to a lower environmental impact. In addition, H-NaOH_low fibers were employed for food container production, and it was found that the obtained product has excellent properties, comparable to those of commercial containers. Full article

Fungal species secrete various enzymes and are considered the primary sources of industrially important cellulases. Cellulases are essential natural factors for cellulose degradation and have attracted significant interest for multiple applications. However, reducing the cost and enhancing cellulase production remains a significant challenge. Mutagenesis has opened a new window for enhancing enzyme secretion by modifying the organism’s genome. In this study, cellulases from Alternaria citri were produced and characterized, and the optimization for ideal fermentation conditions was performed for three types of cellulases (endoglucanase, exoglucanase, and β-glucosidase) by a wild-type (A. citri) and a mutant strain (A. citri 305). Ethyl methanesulfonate, a chemical mutagen, was used to enhance cellulase production by A. citri. The results demonstrate the improved cellulolytic ability of the mutant strain A. citri 305 utilizing lignocellulosic waste substances, particularly, orange-peel powder, wheat straw, sugarcane bagasse, and sawdust, making this study economically valuable. This evokes the potential for multi-dimensional applications in enzyme production, waste degradation, and biofuel generation. This study highlights that the activity of cellulases to hydrolyze various lignocellulosic substrates is enhanced after mutagenesis. Full article

Attempts have been made to replace conventional plastics in food packaging with biodegradable materials as a promising alternative because they are natural, renewable, and low-cost. This study aimed to develop biodegradable and resistant films from cellulose nanofibrils (CNFs) from sugarcane bagasse when used as reinforcement in starch films. Sugarcane bagasse pulps were subjected to alkaline treatment, with the residual lignin remaining. Part of the material was subjected to a bleaching process with H₂O₂. The pulps were subjected to the mechanical fibrillation process, and unbleached and bleached CNFs were produced. Percentages of 10%, 20%, 30%, and 50% CNF were added to a solution containing 2.5% starch (m/m) solids to make the films. The addition of unbleached CNF promoted an average increase in the tensile strength and Young’s modulus values, especially for films with higher percentages of CNF (30% and 50%). The contact angle values increased with the CNF concentration, with all films being classified as hydrophobic (>90°), except for the films with 30% and 50% unbleached CNF. The 50% unbleached and bleached CNF samples showed low water vapor permeability (2.17 g.mm/Kpa⁻¹ day⁻¹ m²), indicating a good vapor barrier. Although the influence of residual lignin on the test results was not identified for the other samples, treatments with 50% CNF of sugarcane bagasse (unbleached or bleached) should be highlighted among the properties evaluated for reinforcing the structure and improving the barrier properties of cassava starch-based films. Furthermore, this study proposes using sugarcane bagasse, which is a waste widely available in Brazil, placing the study in line with three Sustainable Development Goals (SDGs). Full article

This study investigates the impact of sulphuric acid concentration (40% vs. 60%) on the extraction of cellulose nanocrystals (CNCs) from alkali-treated sugarcane bagasse (SCB) and their reinforcement in poly(furfuryl) alcohol (PFA) composites. Probing into the physicochemical changes through scanning electron microscopy (SEM) displayed drastic morphological changes, alkali removal of noncellulosic components followed by sulphuric acid hydrolysis further refined cellulose to nanoscale morphologies. The X-ray diffraction (XRD) study showed that after alkali treatment, the crystallinity was significantly higher (65%), and the crystallinity index of CNCs prepared from 40% H₂SO₄ was greater than the CNCs prepared from 60% H₂SO₄ (61%). Fourier transform infrared spectral and thermogravimetric analysis (TGA) suggested that improving the polymeric performance by the incorporation of a CNC resulted in a decrease in the thermal stability of the modified polyelectrolyte, which was largely attributed to higher sulphate esterification achieved at higher acid concentrations. It is possible to use CNCs to achieve higher mechanical performance while also indicating that optimizing thermal properties and mechanical performance of high-performance materials will require an improved understanding of the microstructural parameters governing the polymer–filler interface. This work demonstrates that acid concentration critically balances CNC crystallinity and thermal performance, offering insights for optimizing sustainable nanocomposites. Full article

The increasing generation of agro-industrial waste and its improper disposal have raised significant environmental concerns, highlighting the urgent need for sustainable alternatives which would repurpose these materials. In this context, enzymes such as endoglucanase play a critical role in degrading lignin–cellulose biomass by catalyzing the breakdown of β-1,4-glycosidic bonds in cellulose, thereby converting it into fermentable sugars with diverse industrial applications. This study aimed to investigate the production, purification, and characterization of an endoglucanase produced by the fungus Pleurotus djamor PLO13, using coconut fiber, sugarcane bagasse, wheat bran, and pineapple crown as substrates. Endoglucanase activity was measured by the Miller method (1959), using 2% (w/v) carboxymethyl cellulose (CMC) as substrate. Solid-state fermentation (SSF) was found to be highly efficient for enzyme synthesis, with wheat bran emerging as the most effective substrate, yielding an enzyme production of 7.19 U after 120 h of cultivation. The endoglucanase was purified through ethanol precipitation and ion-exchange chromatography using DEAE-Sepharose, achieving a recovery rate of 110%, possibly due to removal of inhibitors present in the crude extract. The purified enzyme exhibited stability across a broad pH range and thermostability, with optimal activity at pH 5.0 and 50 °C. Furthermore, the enzyme was activated by EDTA, Mn²⁺, and Ca²⁺, while being inhibited by Mg²⁺. Notably, the enzyme demonstrated halotolerance, with activity increasing by 60% upon the addition of 3 M NaCl. Kinetic analysis revealed that the purified enzyme showed affinity to the CMC substrate at the analyzed parameters (pH 5.0 and 50 °C), with Km and Vmax values of 0.0997 mg/mL and 112.2 µg/min/mL, respectively. These findings suggest that the endoglucanase from P. djamor PLO13 has promising potential for biotechnological applications, underscoring the feasibility of the use of lignocellulosic waste as sustainable substrates in industrial processes. Full article

The valorization of agri-food wastes can provide value-added products, enzymes and biofuels. For the second-generation ethanol (2G) production, pulps rich in cellulose are desirable in order to release fermentable sugars. This study investigated the homemade biosynthesis of cellulases and hemicellulases via solid-state fermentation (SSF) using sugarcane bagasse (SB) and wheat bran (WB) for the growth of endophytic fungi (Beauveria bassiana, Trichoderma asperellum, Metarhizium anisopliae and Pochonia chlamydosporia). Cocktails with high enzymatic levels were obtained, with an emphasis for M. anisopliae in the production of β-glucosidase (83.61 U/g after 288 h) and T. asperellum for xylanase (785.50 U/g after 144 h). This novel M. anisopliae β-glucosidase demonstrated acidophile and thermotolerant properties (optimum activity at pH 5.5 and 60 °C and stability in a wide pH range and up to 60 °C), which are suitable for lignocellulose saccharifications. Hence, the M. anisopliae multi-enzyme blend was selected for the hydrolysis of raw and organosolv-pretreated corn straw (CS) and corncob (CC) using 100 CBU/g cellulose. After the ethanol/water (1:1) pretreatment, solid fractions rich in cellulose (55.27 in CC and 50.70% in CS) and with low concentrations of hemicellulose and lignin were found. Pretreated CC and CS hydrolysates reached a maximum TRS release of 12.48 and 13.68 g/L, with increments of 100.80 and 73.82% in comparison to untreated biomass, respectively, emphasizing the fundamental role of a pretreatment in bioconversions. This is the first report on β-glucosidase biosynthesis using M. anisopliae and its use in biomass hydrolysis. These findings demonstrated a closed-loop strategy for internal enzyme biosynthesis integrated to reducing sugar release which would be applied for further usage in biorefineries. Full article

This research explores the synthesis of carboxymethyl cellulose (CMC) for the development of a cost-effective bioplastic film that can serve as a sustainable alternative to synthetic plastic. Replacing plastic packaging with CMC-based films offers a solution for mitigating environmental pollution, although the inherent hydrophilicity and low mechanical strength of CMC present significant challenges. To address these limitations, zinc oxide nanoparticles (ZnO NPs) were employed as a biocompatible and non-toxic reinforcement filler to improve CMC’s properties. A solution casting method which incorporated varying concentrations of ZnO NPs (0%, 5%, 10%, 15%, 20%, and 25%) into the CMC matrix allowed for the preparation of composite bioplastic films, the physicochemical properties of which were analyzed using scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The results revealed that the ZnO NPs were well-integrated into the CMC matrix, thereby improving the film’s crystallinity, with a significant shift from amorphousness to the crystalline phase. The uniform dispersion of ZnO NPs and the development of hydrogen bonding between ZnO and the CMC matrix resulted in enhanced mechanical properties, with the film CZ₂₀ exhibiting the greatest tensile strength—15.12 ± 1.28 MPa. This film (CZ₂₀) was primarily discussed and compared with the control film in additional comparison graphs. Thermal stability, assessed via thermogravimetric analysis, improved with an increasing percentage of ZnO Nps, while a substantial decrease in water vapor permeability and oil permeability coefficients was observed. In addition, such water-related properties as water contact angle, moisture content, and moisture absorption were also markedly improved. Furthermore, biodegradability studies demonstrated that the films decomposed by 71.43% to 100% within 7 days under ambient conditions when buried in soil. Thus, CMC-based eco-friendly composite films have the clear potential to become viable replacements for conventional plastics in the packaging industry. Full article

The complex structure of the plant cell wall makes it difficult to use the biomass produced by biosynthesis. For this reason, the search for new strains of microorganisms capable of efficiently degrading fiber is a topic of interest. For these reasons, the present study aimed to evaluate both the microbiological and enzymatic characteristics of the fungus Curvularia kusanoi L7strain. For this, its growth in different culture media was evaluated. Wheat straw mineralization was evaluated by gas chromatography assisted by infrared spectroscopy. The production of endo- and exoglucanase, laccase, and peroxidase enzymes in submerged solid fermentation of wheat and sugarcane bagasse were characterized. The strain efficiently mineralized raw wheat straw, showing a significant decrease in signals associated with cellulose, hemicellulose, and lignin in the infrared spectra. High enzyme productions were achieved in submerged solid fermentation of both substrates, highlighting the high production of endoglucanases in sugarcane bagasse (2.87 IU/mL) and laccases in wheat (1.64 IU/mL). It is concluded that C. kusanoi L7 is an ascomycete with a versatile enzyme production that allows it to exhaustively degrade complex fibers such as raw wheat straw and sugar cane bagasse, making it a microorganism with great potential in the bioconversion of plant biomass. Full article

Converting agricultural biomass wastes into bio-chemicals can significantly decrease greenhouse gas emissions and foster global initiatives towards mitigating climate change. This study examined the co-production of xylitol and ethanol from xylose and glucose-rich hydrolysates of corn cob (CC), sugarcane bagasse (SCB), and rice straw (RS) without prior detoxification, using C. magnoliae (C. mag), C. tropicalis (C. trop), and C. guilliermondii (C. guil). A score ranking system based on weighted yields and productivity assessed the best raw material and yeast strain combination. The study revealed that C. mag cultivated on RS hemicellulosic and CC cellulosic media exhibited statistically significant (p ≤ 0.05) superiority in xylitol (272 ± 5) and ethanol 273 ± 3, production. The single-phase emulsion system using frozen-thawed whole cells of CC—C. mag, CC—C. trop, and RS—C. guil was utilized for phenylacetylcarbinol (PAC) biotransformation. Although similar PAC concentration within 14.4–14.7 mM was obtained, the statistically significant higher (p ≤ 0.05) volumetric pyruvate decarboxylase (PDC) activity from C. mag at 360 min was observed by 28.3 ± 1.51%. Consequently, further utilization of CC—C. mag in a two-phase emulsion system (Pi buffer: vegetable oil (Vg. oil) and Pi buffer: deep eutectic solvents (DES)) revealed that Pi buffer: DES medium preserved volumetric PDC activity (54.0 ± 1.2%) statistically significant higher (p ≤ 0.05) than the Pi buffer: Vg. oil system (34.3 ± 1.3%), with no statistically significant difference (p > 0.05) in [PAC]. These findings outlined the sustainable pioneering approach for the co-production of chemicals and reusing the residual yeast cells for PAC biotransformation in the Pi buffer: DES system. Full article

Sugarcane bagasse is rich in cellulose and lignin, and the recycling of bagasse has become an important research field with the increasing global concern for sustainable development and environmental protection. In this paper, TG-MS-FTIR equipment was used to analyze the pyrolysis characteristics of bagasse from Guangxi under different heating rates and different atmospheres, which is conducive to the reuse of bagasse from the waste gas produced in the sugar plant. The results showed that the pyrolysis rate of sugarcane bagasse in the air atmosphere was faster than that in the nitrogen atmosphere and showed a double-peak trend, and the Coats–Redfern computational model could more accurately simulate the process of pyrolysis. The lower heating rate could overcome the heat transfer hysteresis phenomenon in the process of pyrolysis. In the air atmosphere, the contact time between oxygen and volatile products was shorter due to the high heating rate, and more and more complex species were precipitated at 10 °C/min than at 20 °C/min. In the nitrogen atmosphere, it was favorable to produce more kinds and quantities of gas products, because it did not react with oxygen. FTIR detected CH₄, CO, H₂O, CO₂, C-O-C, and C=O during pyrolysis in nitrogen, and some of C-O-C and C=O were cracked into small molecule compounds at high temperature. Full article

The escalating demand for sustainable rubber products has spurred research into alternative reinforcing fillers, driven by concerns regarding the detrimental effects of using conventional fillers like carbon black and silica. In this investigation, nano-crystalline cellulose (NCC), derived from micro crystalline cellulose (MCC), sourced from sugarcane bagasse via acid hydrolysis, serves as a bio-filler to reinforce Nitrile Butadiene Rubber (NBR) matrices. NBR-NCC nano-composites were prepared using a two-roll mill, varying NCC from 1–5 parts per hundred rubber matrices, followed by hot press curing. NCC and NBR-NCC nano-composites were characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), curing characteristics, thermo-mechanical testing, thermal aging and motor oil resistance. Chemical interactions between the NCC and NBR matrix were verified with FTIR. The SEM images of the NCC showed a combination of rod-like and spherical morphologies and a homogenous dispersion of NCC in NBR-NCC nano-composites with some agglomeration, notably at higher percentages of NCC. It is shown that the cure time decreases with increasing NCC loading which mimics a shorter industrial production cycle. The results also showed an increase in tensile strength, hardness, oil resistance and a rise in degradation temperature when compared to NBR at approximately 34%, 36%, 38% and 32 °C, respectively, at 3 phr NCC loading. Furthermore, NBR-NCC nano-composites showed a lower decrease in mechanical properties after aging when compared to NBR. The findings of this research suggest that the NBR-NCC nano-composites may find applications in high oil resistance seals and rubber gloves where higher thermal stability is strictly required. Full article

Carboxymethyl cellulose (CMC) was prepared from sugarcane bagasse (SB) in minutes using a novel microwave method. Additionally, nitrogen-doped carbon dots (N–CDs) were synthesized from SB using the same microwave technique. These materials were crosslinked with CaCl₂ to prepare antibacterial/antifungal hydrogel sensors. In this regard, both CMC@Ca and CMC@Ca-N–CDs exhibited antibacterial activity against Escherichia coli (Gram negative), while only CMC@Ca-N–CDs demonstrated antibacterial activity against Staphylococcus aureus (Gram positive). Moreover, both materials showed antifungal activity against Candida albicans. The molecular docking study demonstrated that CMC@Ca-N–CDs showed good binding with proteins with short bond length 2.59, 2.80, and 1.97 A° for Escherichia coli, Staphylococcus aureus, and Candida albicans, respectively. These binding affinities were corroborated by the observed inhibition zone diameters. Furthermore, fluorescence microscope revealed distinct imaging patterns between Gram-positive and Gram-negative bacteria, as well as pathogenic yeast (fungi). CMC@Ca-N–CDs emitted blue light when exposed to Escherichia coli and Candida albicans (i.e., CMC@Ca-N–CDs/Escherichia coli and Candida albicans), whereas it emitted bright-red light when exposed to Staphylococcus aureus (i.e., CMC@Ca-N–CDs/Staphylococcus aureus). This disparity in the fluorescence-emitted colors is due to the difference in the cell wall of these microorganisms. Additionally, DFT calculations were conducted to substantiate the robust chemical interactions between CMC, Ca²⁺, and N–CDs. Full article

In this paper, we present the synthesis of composite materials comprised of α-cellulose and sugarcane bagasse cellulose fibers grafted with lactic acid and ε-caprolactone. These fibers were incorporated as reinforcements into a PLA matrix by extrusion, producing composite materials with improved mechanical properties. The grafting of lactic acid and ε-caprolactone onto the fibers was confirmed by FTIR spectroscopy, demonstrating the chemical modification of the fibers. The morphology of the fibers and composites was analyzed through scanning electron microscopy (SEM), showing that the fibers are encapsulated within the polymeric matrix. This suggests good PLA–fiber interaction for the 90 PLA/10 α-Cel, 90 PLA/10 LAC-g-α-Cel, and 90 PLA/10 ε-CL-g-α-Cel composite materials. The obtained composite materials were tested under tensile loading. Incorporating 10 wt% of LAC-g-FBA-Cel and α-Cel-g-FBA-Cel grafted fibers into the PLA matrix improved the tensile modulus by 28% and 12%, respectively, compared with PLA. The maximum tensile strength values obtained were for composite materials with 10 wt% PLA/α-Cel, LAC-g-α-Cel, and FBA-Cel with 23, 27, and 37% concerning PLA. DSC thermal studies showed a reduction in the glass transition temperature in the composites with grafted fibers. The results suggest better interfacial adhesion between the PLA matrix and both grafted and non-grafted α-cellulose fibers, which contributes to the observed improvements in the mechanical and thermal properties of the composite materials. The results demonstrate that the composites can be produced through extrusion. Once the optimal concentration has been determined, α-cellulose or sugarcane bagasse grafted with lactic acid and ε-caprolactone can be incorporated into the PLA matrix, exhibiting adjustable properties. Full article