Search Results (181)

Natural-fiber-reinforced polypropylene (PP) composites are gaining increasing interest as lightweight, sustainable alternatives for various packaging and applications. This study investigates the effect of filler addition sequence on the mechanical, morphological, thermal, and dynamic mechanical properties of PP-based composites reinforced with graphite nanoplatelets (GnP) and kenaf fiber (KF). Two filler incorporation sequences were evaluated: GnP/KF/PP (GnP initially mixed with KF before PP addition) and GnP/PP/KF (KF added after mixing GnP with PP). The GnP/KF/PP composite exhibited superior mechanical properties, with tensile strength and flexural strength increasing by up to 25% compared to the control, while GnP/PP/KF showed a 13% improvement. SEM analyses revealed that initial mixing of GnP with KF significantly improved filler dispersion and interfacial bonding, enhancing stress transfer within the composite. XRD and DSC analyses showed reduced crystallinity and lower crystallization temperatures in the addition of KF due to restricted polymer chain mobility. Thermal stability assessed by TGA indicated minimal differences between the composites regardless of filler sequence. DMA results demonstrated a significantly higher storage modulus and enhanced elastic response in the addition of KF, alongside a slight decrease in glass transition temperature (T_g). The results emphasize the importance of optimizing filler addition sequences to enhance mechanical performance, confirming the potential of these composites in sustainable packaging and structural automotive applications. Full article

Introducing and compacting lignocellulosic biomass in aluminum structures, though recommendable in terms of higher sustainability, the potential use of agro-waste and significant weight reduction, still represents a challenge. This is due to the variability of biomass performance and to its limited compatibility with the metal. Another question may concern possible moisture penetration in the structure, which may reduce environmental resistance and result in local degradation, such as wear or even corrosion. Despite these limitations, this hybridization enjoys increasing success. Two forms are possibly available for this: introduction into metal matrix composites (MMCs), normally in the form of char from biomass combustion, or laminate reinforcement as the core for fiber metal laminates (FMLs). These two cases are treated alongside each other in this review, first because they may represent two combined options for recycling the same biomass into high-profile structures, aimed primarily at the aerospace industry. Moreover, as discussed above, the effect on the aluminum alloy can be compared and the forces to which they are subjected might be of a similar type, most particularly in terms of their hardness and impact. Both cases considered, MMCs and FMLs involved over time many lignocellulosic residues, starting from the most classical bast species, i.e., flax, hemp, sisal, kenaf, etc., and extending also to less diffuse ones, especially in view of the introduction of biomass as secondary, or residual, raw materials. Full article

Background: The aim of this study was to develop a genetic transformation system to construct an overexpression vector for the mitochondrial gene atp6 in tobacco, thereby providing a foundation to investigate the functional roles of mitochondrial genes in this species. Methods: A full-length coding sequence (CDS) of the atp6 gene from a sterile line was cloned, along with the mitochondrial leader peptide sequence of atp2-1 from tobacco, using cDNA from kenaf UG93A anthers as a template. An overexpression vector for plants was constructed by employing In-Fusion technology, and wild-type tobacco plants were transformed via Agrobacterium-mediated transformation. Transgenic tobacco plants were then subjected to resistance screening and PCR validation. Results: The overexpression vector PBI121-atp2-1-atp6-EGFP, which includeds the mitochondrial leader peptide sequence, was successfully constructed. PCR validation using two pairs of primers targeting different sites on the overexpression vector confirmed the stable expression of the target gene in six transgenic tobacco plants (H1, H3, H4, H5, H7, and H8) via both primer pairs. A phenotypic analysis and iodine–potassium iodide (I₂-KI) staining of pollen grains from transgenic tobacco plants revealed the presence of shriveled and malformed pollen grains with reduced viability. These findings suggest that the atp6A gene, including the mitochondrial signal peptide, induces pollen abortion in tobacco. Conclusions: The genetic transformation system developed for the vector overexpressing the atp6 mitochondrial gene from kenaf provides a valuable framework to investigate the molecular regulatory mechanisms underlying the role of the atp6 gene in kenaf cytoplasmic male sterility (CMS). Full article

This novel study explores a comprehensive approach, combining fiber and matrix structure–property relationships. By integrating alkali treatment, fiber mapping, and intrinsic fiber properties, this work offers a unique perspective on the mechanical, physical, and thermal properties of biodegradable composites of reinforced polypropylene (PP) and plasticized poly (lactic acid) (PLA), with 25 wt% Kenaf (KBF), Bagasse, Hemp fibers and softwood fibers serving as a control. To enhance fiber–matrix interaction, fibers underwent alkaline treatment using 5% sodium hydroxide (NaOH) for one hour. The mechanical properties, including tensile strength, Young’s modulus, and impact strength, were evaluated alongside physical and thermal properties such as fiber mapping, brightness, heat deflection temperature (HDT), melting temperature, melt flow ratio (MFR), and melt flow index (MFI). Scanning electron microscopy (SEM) was used to assess the biocomposites’ morphology. The results showed that fiber reinforcement improved the tensile and impact strength of PP composites, particularly for treated Bagasse (6.6% and 22%) and Hemp (7% and 44.7%), while Kenaf exhibited minimal change, indicating its inherently high strength. A slight increase in tensile strength and Young’s modulus was observed in all PLA-based composites. The addition of 25% fiber enhanced the thermal properties of both treated and untreated fiber-reinforced composites. Among PP composites, those reinforced with treated fibers exhibited the highest HDT, with Kenaf achieving the best performance (124 °C), followed by Bagasse (93 °C). The HDT values for untreated fibers were 119 °C for KBF, 100 °C for softwood, 86 °C for Bagasse, and 79 °C for Hemp. PLA composites showed a slight increase in HDT with fiber reinforcement. Differential Scanning Calorimetry (DSC) revealed a slight decrease in melting temperature for PP composites and a slight increase for PLA composites. Fiber mapping analysis indicated that Kenaf had the highest aspect ratio, contributing to superior mechanical performance, while Hemp had the lowest aspect ratio and exhibited weaker mechanical properties. Overall, Kenaf and Bagasse fibers demonstrated superior mechanical and thermal properties, comparable to those of softwood fibers, whereas Hemp exhibited moderate performance. The variations in composites behavior were attributed to differences in fiber mapping, alkaline treatment, and the intrinsic properties of both the polymer matrices and the reinforcing fibers. These findings highlight the potential of treated natural fibers, particularly Kenaf and Bagasse, in enhancing the mechanical and thermal properties of biodegradable composites, reinforcing their suitability for sustainable material applications. Full article

Fiber-reinforced composites are widely utilized across various industries, including aerospace, automotive, and marine, due to their outstanding mechanical properties and lightweight characteristics. Natural fibers, as promising reinforcements, have the potential to replace synthetic fibers in certain areas to meet the growing demand for environmental protection and sustainability. These biocomposites offer numerous benefits, including reduced carbon footprints, diminished reliance on non-renewable resources, and increased natural biodegradability. In addition, utilizing such eco-friendly materials is a critical strategy for balancing industry progress and environmental protection. Kenaf fiber, a superior bast fiber known for its excellent mechanical properties and high cellulose content, presents considerable advantages for enhancing the performance of biocomposites. This review explores the potential of kenaf fiber-reinforced biocomposites for marine applications, focusing on their fabrication and testing methods to evaluate their physicochemical and mechanical properties. This paper examines the chemical composition and mechanical properties of the kenaf fiber, investigates the excellent performance advantages of kenaf fiber-based biocomposites by hybridization manufacturing, and provides an overview of the status and challenges of applying such biocomposites in marine environments. Based on this review, it is evident that kenaf fiber-reinforced biocomposites have significant superiority for marine applications with the advancement of manufacturing techniques. Full article

In this study, kenaf-derived activated carbons (AK-AC) was prepared for automobile canisters via chemical stabilization and physical activation methods. The thermogravimetric analysis and differential thermogravimetry revealed a crystallite change in the kenaf with chemical stabilization. The AK-AC texture properties were studied using the Brunauer–Emmett–Teller, Dubinin–Radushkevitch, and non-local density functional theory equations, with N₂/77K isotherm adsorption–desorption curves. The AK-AC nanocrystallite characteristics were observed through X-ray diffraction and Raman spectroscopy. The AK-AC butane adsorption characteristics were analyzed via breakthrough curves and compared with those of commercial coconut-derived activated carbon (Coconut AC). As the activation time increased, the specific surface area and mesopore volume ratio of the AK-AC increased to 1080–1940 m²/g and 10.6–50.0%, respectively. The AK-AC also exhibited better mesoporous pore characteristics than the Coconut AC. The AK-AC butane adsorption capacity increased from 0.31 to 0.79 g/g. In particular, the AK-AC had an approximately 50% improved butane adsorption capacity compared to the Coconut AC. In addition, the butane adsorption characteristics of the AK-AC were determined using the mesopore volume, with a diameter of 3.0–4.0 nm. The results suggest that AK-AC may be proposed as an adsorbent to improve evaporative emissions from automotive canisters in the future. Full article

Salicylic acid (SA) plays a crucial role in alleviating drought stress in plants. However, little is known about the molecular mechanisms underlying exogenous SA on the drought tolerance of kenaf. In this study, the kenaf seedlings were subjected to physiological and transcriptomic analysis under control (CK), moderate drought stress (D), and moderate drought stress with 1 mM SA (D_SA). Under drought conditions, SA significantly improved the plant biomass, leaf area, antioxidant enzyme activities (SOD, POD, and CAT), soluble sugars, starch and proline contents, and photosynthesis, while the contents of MDA, H₂O₂, and O₂⁻ were significantly decreased. A total of 3430 (1118 up-regulated and 2312 down-regulated) genes were differentially expressed in group D, compared with group CK. At the same time, 92 (56 up-regulated and 36 down-regulated) genes were differentially expressed in group D_SA compared with group D. GO and KEGG analysis showed that the differentially expressed genes (DEGs) were enriched in various metabolic pathways, such as carbohydrate metabolism, lipid metabolism, and the metabolism of terpenoids and polyketides. Results showed that the genes related to the antioxidant system, sucrose and starch synthesis, osmoregulation, ABA signal regulation, and differentially expressed transcription factors, such as AP2/ERF4 and NF-Y1, were involved in the increased drought tolerance of kenaf under exogenous SA. Virus-induced gene silencing (VIGS)-mediated silencing of salicylate binding protein 2 gene (HcSABP2) decreased the drought resistance of kenaf seedlings. Thus, the present study provides valuable insights into the regulatory mechanism of exogenous SA in alleviating drought stress in kenaf. Full article

Palm oil mill effluent (POME) is a major contributor to industrial oily wastewater in Malaysia, demanding effective treatment solutions. This study explores the potential of esterified kenaf core (EKC) fiber as an oil adsorbent for oil removal from POME, optimized using a full central composite design (CCD) within the response surface methodology (RSM) framework. The optimum conditions achieved 76% oil removal efficiency, with a 1:0.5 ratio of mercerized kenaf core to stearic acid (MKC:SA), 15 wt% of catalyst, and 1 h reflux time during the esterification process. The regression model exhibited strong predictive capability, with a significant quadratic correlation and an R² value of 0.94. The Fourier transform infrared (FTIR) spectroscopy revealed the existence of ester functional groups characterized by significant hydrophobicity and a decrease in hydroxyl groups, indicating the chemical changes of EKC. Moreover, the scanning electron microscopy (SEM) research demonstrated structural alterations in EKC, including heightened surface roughness, fibrillation, and pore development, which improved oil adhesion relative to raw kenaf core (RKC). These findings indicate that EKC provides an effective, environmentally sustainable solution for managing oil wastewater issues in the palm oil sector, facilitating enhanced ecological sustainability and resource management. Full article

The current study investigated the in vitro degradability, in vitro gas production, methane (CH₄) production, and ruminal bacterial community of kenaf plants cut at different heights (130, 160, 190, 220, and 250 cm). These samples were subjected to an in vitro batch culture system using buffalo rumen fluid to measure gas and CH₄ production at 3, 6, 9, 12, 24, 36, 48, and 72 h of incubation. Results reveal that crude protein (CP) concentration was the highest at the 220 cm height compared with the other heights. With the increase in height, gas and CH₄ production decreased. However, the CH₄ production at 190 cm was higher compared with the other plant heights. Dry matter degradation was higher at 190 cm and 220 cm, while ammonia-N and microbial CP were higher at the 220 cm height compared with the other heights. However, neutral detergent fiber degradation was the highest at the 130 cm height. Total volatile fatty acids, acetic acid, acetic acid/propane ratio, and pH value did not differ among the treatments, except for propionic acid, which was higher at the 130 cm and 160 cm heights. Overall, harvesting kenaf at plant heights of up to 220 cm was better in terms of its promising nutritional quality, improved dry matter degradation, and microbial CP contents. Full article

Cellulosic biomass hydrolysates are rich in glucose and xylose, but most microorganisms, including Komagataella phaffii, are unable to utilize xylose effectively. To address this limitation, we engineered a K. phaffii strain optimized for xylose metabolism through the xylose oxidoreductase pathway and promoter optimization. A promoter library with varying strengths was used to fine-tune the expression levels of the XYL1, XYL2, and XYL3 genes, resulting in a strain with a strong promoter for XYL2 and weaker promoters for XYL1 and XYL3. This engineered strain exhibited superior growth, achieving 14 g cells/L and a maximal growth rate of 0.4 g cells/L-h in kenaf hydrolysate, outperforming a native strain by 17%. This study is the first to report the introduction of the xylose oxidoreductase pathway into K. phaffii, demonstrating its potential as an industrial platform for producing yeast protein and other products from cellulosic biomass. Full article

Heavy metal pollution is one of the most devastating abiotic factors, significantly damaging crops and human health. One of the serious problems it causes is a rise in cadmium (Cd) toxicity. Cd is a highly toxic metal with a negative biological role, and it enters plants via the soil–plant system. Cd stress induces a series of disorders in plants’ morphological, physiological, and biochemical processes and initiates the inhibition of seed germination, ultimately resulting in reduced growth. Fiber crops such as kenaf, jute, hemp, cotton, and flax have high industrial importance and often face the issue of Cd toxicity. Various techniques have been introduced to counter the rising threats of Cd toxicity, including reducing Cd content in the soil, mitigating the effects of Cd stress, and genetic improvements in plant tolerance against this stress. For decades, plant breeders have been trying to develop Cd-tolerant fiber crops through the identification and transformation of novel genes. Still, the complex mechanism of Cd tolerance has hindered the progress of genetic breeding. These crops are ideal candidates for the phytoremediation of heavy metals in contaminated soils. Hence, increased Cd uptake, accumulation, and translocation in below-ground parts (roots) and above-ground parts (shoots, leaves, and stems) can help clean agricultural lands for safe use for food crops. Earlier studies indicated that reducing Cd uptake, detoxification, reducing the effects of Cd stress, and developing plant tolerance to these stresses through the identification of novel genes are fruitful approaches. This review aims to highlight the role of some conventional and molecular techniques in reducing the threats of Cd stress in some key fiber crops. Molecular techniques mainly involve QTL mapping and GWAS. However, more focus has been given to the use of transcriptome and TFs analysis to explore the potential genomic regions involved in Cd tolerance in these crops. This review will serve as a source of valuable genetic information on key fiber crops, allowing for further in-depth analyses of Cd tolerance to identify the critical genes for molecular breeding, like genetic engineering and CRISPR/Cas9. Full article

Background/Objectives: Diesel Particulate Matter (DPM) is a very small particulate matter originating from cities, factories, and the use of fossil fuels in diesel vehicles. When DPM permeates the skin, it causes inflammation, leading to severe atopic dermatitis. Hibiscus cannabinus L. (Kenaf) seeds and leaves possess various beneficial properties, including anti-coagulation, antioxidant, and anti-inflammation effects. In this study, we investigated the anti-inflammatory effects of an ethanol extract of Hibiscus cannabinus L. flower (HCFE) in HaCaT cells stimulated with 100 μg/mL of DPM. Methods: The anthocyanin content of HCFE was analyzed, and its antioxidant capacity was investigated using the DPPH assay. After inducing inflammation with 100 ug/mL of DPM, the cytotoxicity of HCFE 25, 50, and 100 ug/mL was measured, and the inhibitory effect of HCFE on inflammatory mediators was evaluated. Results: Anthocyanin and myricetin-3-O-glucoside were present in HCFE and showed high antioxidant capacity. In addition, HCFE decreased the mRNA expression of inflammatory cytokines and chemokines such as IL-1β, IL-4, IL-6, IL-8, IL-13, and MCP-1, and significantly reduced the gene expression of CXCL10, CCL5, CCL17, and CCL22, which are known to increase in atopic dermatitis lesions. Furthermore, HCFE reduced intracellular reactive oxygen species (ROS) production, and down-regulated the activation of NF-κB, MAPKs. Inhibition of the NLRP-3 inflammasome was observed in DPM-stimulated HaCaT cells. In addition, the restoration of filaggrin and involucrin, skin barrier proteins destroyed by DPM exposure, was confirmed. Conclusions: These data suggest that HCFE could be used to prevent and improve skin inflammation and atopic dermatitis through the regulation of inflammatory mediators and the inhibition of skin water loss. Full article

Activated carbons were prepared from kenaf (Hibiscus cannabinus L.). Carbonization was carried out at 600 °C for 2 h, and activation was performed using air at 600 °C and using CO₂ at 750 °C. The activated carbons obtained were treated with HNO₃ and H₂SO₄. The samples were characterized by their chemical and physical structure. The activated carbons obtained were mainly macroporous, and their structure underwent major changes with the activation method and acid treatment. Activated carbons were alkaline and acid-treated carbons were neutral. They were used for phenol adsorption and a kinetic and mechanistic study of adsorption was carried out. The fit to the pseudo-second order and Elovich models was predominant. The rate-limiting step of the process was determined to be diffusion within the pores, as the experimental data fit the Bangham model. DFT simulation showed that the preferred adsorption position involves π-π stacking and that oxidation enhances this interaction. Furthermore, the simulation showed that the interaction of phenol with oxygenated functional groups depends on the type of functional group. Full article

Kenaf (Hibiscus cannabinu) is a grass bast fiber crop that has the ability to tolerate and accumulate heavy metals, and it has been considered as a potential heavy metal accumulator and remediation plant. Nramp is a natural resistance-related macrophage, which plays an important role in the transport of divalent metal ions, plant growth and development, and abiotic stress. In this study, the Nramp gene family of kenaf was analyzed at the whole genome level. A total of 15 HcNramp genes were identified. They are distributed unevenly on chromosomes. Phylogenetic analysis classified 15 HcNramp proteins into 3 different subfamilies. All proteins share specific motif 4 and motif 6, and the genes belonging to the same subfamily are similar in structure and motif. The promoters are rich in hormone response, meristem expression, and environmental stress response elements. Under different treatments, the expression levels of HcNramp genes vary in different tissues, and most of them are expressed in roots first. These findings can provide a basis for understanding the potential role of the Nramp gene family in kenaf in response to cadmium (Cd) stress, and are of great significance for screening related Cd tolerance genes in kenaf. Full article

Hibiscus cannabinus (kenaf) is an annual fiber crop grown in warm seasons and known for its remarkable productivity; it has been cultivated worldwide for thousands of years as a fiber source. While every part of the plant can be utilized for some purpose, its primary significance lies in the diverse applications of its cellulosic fiber. Kenaf features a blend of long bast and short core fibers, rendering it suitable for various industrial uses. Initially utilized for cordage and livestock feed, kenaf’s applications have expanded over the last century to encompass its utilization as paper pulp, biocomposites, textiles, biomass energy, seed oil, filtration aids, industrial absorbents, and even as a component of potting medium or as a potential source of medicine. Although traditionally a niche crop, the discovery of its diverse applications positions kenaf for rapid expansion in production in the upcoming decades. This article aims to explore the manifold applications of kenaf, highlighting those with the greatest future potential and discussing those that hold promise for commercial-level application with additional research. Full article