Sisal Research Articles

Effect of polyaramid reinforced with sisal epoxy composites: Tensile, impact, flexural and morphological properties

Natural fiber reinforced polymers have been intensively studied in a wide range of application in the material science. The sisal fibers, which extracted from Agave sisalana plant, stand out due to their good mechanical properties, simple cultivation and reasonable cost. In the present work, the effect of addition of 5% polyaramid fibers, in the structure and properties of epoxy matrix composite reinforced with modified sisal fibers investigated. The ratio of 40, 50 and 60 wt. % sisal fiber-reinforced composites were prepared by hand lay-up technique, with and without the addition of polyaramid. Tensile, flexural and Izod impact tests performed, and the fracture aspect observed. Analytical techniques such as SEM, TEM and TGA have performed to investigate the structural changes. The results also indicated epoxy matrix composite reinforced with modified sisal fibers possesses good tensile, flexural and impact strength.

Relationship between Leaf and Fibre Characteristics of Agave sisalana

With decrease in wood from the forest, non-wood fibres have attracted interest in the production of pulp and paper products in recent times due to their short growth cycles, moderate irrigation and fertilizer requirements as well as their low lignin content. The use of these plants will aid sustainable development in the pulp and paper industry. This study investigated leaf dimensions and fibre characteristics of Agave sisalana and how the leaf dimensions relates to its fibre characteristics. Leaves were collected from three sisal plant stands in Oyo State, Nigeria. The plant whorl was divided systematically into bottom, middle and top from which five leaves were randomly collected from each whorl position. The fibres of the leaves were extracted from which 2cm of fibres were taken from three positions on the leaf (top, middle and base). Extracted fibres were macerated and 3375 fibres were measured. The result shows that Agave sisalana leaves collected at the top had the longest length and was also widest at the base and middle. The average fibre length was 1.69 mm, while the fibre diameter, lumen width and cell wall thickness of Agave sisalana were 16.98 µm, 12.33 µm and 2.32 µm respectively. The slenderness ratio averaged 99.4 while the coefficient of flexibility averaged 72.61. The highest value of the runkel ratio of Agave sisalana was 0.42. There was significant negative correlation between leaf characteristics and fibre characteristics. Young sisal (Agave sisalana) leaves produced the best fibre characteristics suitable for the production of high quality paper.

Experimental investigation on the potentials of Sisal Fibres as Reinforcements for Drainage Concrete Cover Plates

With the development of infrastructures in Rwanda, the roads construction has been one of busiest area, and as the country counts thousands hills the design and construction of drainage systems required a great attention. Most of road drainage channels are covered with concrete plates that are reinforced with ordinary steel bars, while others are not covered due to the high cost of reinforced concrete plates. As the majority of these plates are only subjected to light pedestrian loads, they should be reinforced accordingly. This study was intended to check the potentials of sisal fibres from Agave Sisalana’ cactus plant which has shown good results in flexural members, as plates reinforcements. At first the quality of ordinary concrete components was checked. Then some of sisal fibres were prepared, manufactured into ropes of 10 mm diameter and then used as replacements of main steel bars in concrete plates before their tensile capacity was checked. Other pieces of sisal fibres of 5 cm length were mixed in concrete mass with different percentages of 0.5%, 1% and 1.5% of concrete volume. Test results showed that the compressive, tensile and flexural strengths for concrete with 1% of sisal fibres were more adequate for M30 concrete and therefore able of sustaining the real loads applied to the drainage concrete cover plates. As the performance of natural sisal fibres depends on fibres treatment methods, length, and type of required concrete, further studies on the use of sisal fibres should consider those factors.
 Keywords: Agave sisalana, drainage channel, Reinforced Concrete, Sisal Fibres, Sisal ropes.

Influence of plasma treatment on the physical and chemical properties of sisal fibers and environmental application in adsorption of methylene blue

The sisal fiber (agave sisalana) is a natural material that presents interesting physical and chemical properties, such as, good adsorption capacity, biodegradability and possibility to be used in composites. Improving these properties is of great importance since sisal fiber may be used in various technological applications. The aim of this work was to study the influence of surface treatment on sisal fibers properties and its effect over methylene blue (MB) adsorption using kinetics models and isotherms studies. The treatment herein used was reactive microwave-assisted cold plasma using mixtures of Ar and CO2, which appears as an alternative to traditional chemical treatments. The adsorption kinetics studies were conducted in order to elucidate the behavior between adsorbent and adsorbate. For this purpose, two isotherm models were used, (i) Redlich-Peterson and (ii) Langmuir. The results show that the plasma treatment promoted an increase in fiber surface roughness, a slight and insignificant decrease in the fiber crystallinity index as well as the breaking and removal of hydroxyl groups with consequent modification of the lignocellulosic material’s original structure. The surface modification of sisal fibers by using cold plasma method promoted greater removal of the MB molecules reaching a 96 %. Kinetic and isotherm studies indicated that the adsorption mechanisms were favorable for both fibers and probably occurred in heterogeneous sites for both pristine and plasma-treated fibers. It was observed that the plasma treatment did not cause the loss of the original properties of the fibers and plays a fundamental role in increasing the adsorption, being indicated for wastewater pollutant removal processes at a low production cost as an alternative to the chemical process currently used.

Plantas etnomedicinales para uso veterinario en comunidades gitanas del noreste de Brasil

Gypsies have been in Brazil since the 16th century and today they are more than 800,000 in the country. This article describes the veterinary use of plants by Calon gypsies living in Pernambuco, Northeastern Brazil. The research was carried out with 23 people (> 40 years old), using semi-structured forms and the snowball technique. The cited species were collected during guided tours, identified and deposited at the IPA and UFP herbaria. Ten plants were indicated for veterinary use: Agave sisalana (Asparagaceae), Aspidosperma pyrifolium (Apocynaceae), Apodanthera congestiflora (Cucurbitaceae), Heliotropium indicum (Boraginaceae), Lippia alba (Verbenaceae), Momordica charantia (Cucurbitaceae), Nicotiana tabacum (Solanaceae), Passiflora cincinnata (Passifloraceae), Phaseolus lunatus (Fabaceae), and Solanum paniculatum (Solanaceae). The participants cited various methods of preparation and therapeutic indications for ectoparasitic infections, digestive disorders, and eye and respiratory infections in farm animals. Apodanthera congestiflora and H. indicum stood out for prophylaxis and treatment of Newcastle disease in fowl.

Effects of alkali treatment on the mechanical and thermal properties of sisal/cattail polyester commingled composites

Environmental and energy conservation pressure has led to a dramatic increase in the need for economically feasible lightweight materials that can be better substitutes for non-biodegradable materials in reinforced composites. In this study, the mechanical and thermal properties of polyester resin composites hybridized with a blend of untreated and alkali treated sisal (Agave sisalana) and cattail (Typha angustifolia) fibers were evaluated. Composites were fabricated by a hand lay-up technique at an optimal hybrid fiber weight fraction of 20 wt% and a constant sisal/cattail fiber blend ratio of 75/25. Flexural, tensile, compressive and impact strengths and moduli, as well as thermal conductivity of the composites, were evaluated following ASTM and ISO test methods. Analytical results indicated that alkali pre-treatment of the fibers enhanced the mechanical properties of the hybrid polyester composites though only marginal differences were recorded in the thermal conductivity of the composites fabricated with treated and untreated fiber blends. Morphological examination revealed that the major failure modes were fiber pull-outs and fiber fracture in composites fabricated with untreated and treated fiber blends, respectively. The composites produced could find non-structural applications as ceiling boards, electronic and food packaging materials but their properties such as wettability, crystallinity, flammability and other thermal properties need to be further investigated.

Identification and validation of superior housekeeping gene(s) for qRT-PCR data normalization in Agave sisalana (a CAM-plant) under abiotic stresses.

The adaptive mechanisms in Agave species enable them to survive and exhibit remarkable tolerance to abiotic stresses. Quantitative real-time PCR is a highly reliable approach for validation of targeted differential gene expression. However, stable housekeeping gene(s) is prerequisite for accurate normalization of expression data by qRT-PCR. Till date, no systematic validation study for candidate housekeeping gene identification or evaluation has been carried-out in Agavespecies. A total of 17 candidate housekeeping genes were identified from the de novo assembled transcriptomic data of A. sisalana and rigorously analyzed for expression stability assessment under drought, heat, cold and NaCl stress. Different statistical algorithms like geNorm, BestKeeper, NormFinder, and RefFinder on expression data determined the superior housekeeping gene(s) for accurate normalization of the gene of interest (GOI). The comprehensive evaluation revealed the β-Tub 4, WIN-1 and CYC-A as the most stable, while EEF1α, GAPDH, and UBE2 were ranked as the least stable genes in pooled samples. Pairwise combination by geNorm showed that up to two housekeeping genes would be adequate to normalize the GOI expression data precisely. Validation of identified most and least stable housekeeping genes was carried-out by normalizing the expression data of AsHSP20 under abiotic stress conditions. Copy number of AsHSP20 gene supports the reliability of the genes used for normalization. This is the first report on the screening and validation of the housekeeping genes under abiotic stress condition in A. sisalana that would assist to understand the stress tolerance mechanisms by novel gene identification and accurate validation.

Flower-like MnO2 on layered carbon derived from sisal hemp for asymmetric supercapacitor with enhanced energy density

MnO2 has been considered as a very promising positive electrode candidate for high energy density asymmetric supercapacitors (ASCs) because of high theoretical capacitance. However, the electrochemical performance of pure MnO2 for ASCs has still been severely limited by poor electronic conductivity, volume expansion and dissolution problem. Herein, we report flower-like MnO2-carbon composite (MnO2/SHAC) as positive electrode and layered Sisal Hemp Active Carbon (SHAC) as negative electrode for high-energy ASCs. The flower-like MnO2/SHAC positive electrode comprised a number of interconnected thin nano-flakes with a length of about 50–100 nm and a thickness of about 10 nm and exhibited a large specific surface area of 189.6 m2 g−1 and good conductivity. The SHAC negative electrode showed multi-layered graphene-like structure and a high BET surface area of 1303.5 m2 g−1. Moreover, the assembled MnO2/SHAC//SHAC ASC exhibits a maximum energy density of 46.2 Wh kg−1 at 0.1 A g−1 and a maximum power density of 3679.5 W kg−1 at 6 A g−1, suggesting that MnO2/SHAC composite has promising potential for practical supercapacitors with enhanced energy.

SAPONINS AND SAPOGENINS OF AGAVE WITH RESPECT TO DIVERSE PHARMACOLOGICAL ROLE OF HECOGENIN

The review outlines the current understandings of saponins and sapogenins in agave species with special focus on pharmacological role of hecogenin in numerous preclinical studies. A systematic literature survey was done on the pharmacological activities of hecogenin during the past 40 y with electronic databases like PubMed, Science Direct, Wiley, SciFinder, Google Scholar, Web of Science and Scopus. Hecogenin, a steroidal sapogenin found abundantly in the leaves of Agave genus species such as, Agave sisalana, Agave cantala, Agave aurea and many more. This phytosteroid (hecogenin) is used as initial material for the synthesis of steroidal drugs in the pharmaceutical industry. Hecogenin has exhibited potential role in the management of a number of disorders such as inflammation, arthritis, cancer, gastric ulcer, cardiotonic and larvicidal activity. In this review, we have summarized the saponins and sapogenins present in the Agave species and pharmacological roles of hecogenin with their mechanism of action.

SISALIN BİTÜMLÜ SICAK KARIŞIM İÇERİSİNDE LİF OLARAK KULLANILABİLİRLİĞİNİN ARAŞTIRILMASI

Hot mix asphalt (HMA) is very common as a highway construction material. Although investment costs are lower than other pavements, HMA needs maintenance and rehabilitation (M&R) more often because of environmental conditions. The time needed for M&R can be extended by using fibers in the mixture. In this study, utility of sisal (Agave Sisalana) plants’ fibers are investigated in HMA. Initially, optimum bitumen content according to best aggregate gradation is determined using Superpave volumetric mix design process. Then, fiber is prepared as short (~3 cm) and long (15 – 100 cm) pieces. Prepared fibers are added into HMA mixtures at different ratios (1, 2 and 3‰ by weight of mixture) based on optimum bitumen content. 1‰ short sisal fiber added specimen gave the best unconditioned indirect tensile strength values, and also long fibers gave best tensile strength ratios.

Preparation of Lignocellulose-Based Activated Carbon Paper as a Manganese Dioxide Carrier for Adsorption and in-situ Catalytic Degradation of Formaldehyde.

Formaldehyde is a colorless, highly toxic, and flammable gas that is harmful to human health. Recently, many efforts have been devoted to the application of activated carbon to absorb formaldehyde. In this work, lignocellulose-based activated carbon fiber paper (LACFP) loaded with manganese dioxide (MnO2) was fabricated for the adsorption and in-situ catalytic degradation of formaldehyde. LACFP was prepared by two-stage carbonization and activation of sisal hemp pulp-formed paper and was then impregnated with manganese sulfate (MnSO4) and potassium permanganate (KMnO4) solutions; MnO2 then formed by in situ growth on the LACFP base by calcination. The catalytic performance of MnO2-loaded LACFP for formaldehyde was then investigated. It was found that the suitable carbonization conditions were elevating the temperature first by raising it at 10°C/min from room temperature to 280°C, then at 2°C/min from 280 to 400°C, maintaining the temperature at 400°C for 1 h, and then increasing it quickly from 400 to 700°C at 15°C/min. The conditions used for activation were similar to those for carbonization, with the temperature additionally being held at 700°C for 2 h. The conditions mentioned above were optimized to maintain the fiber structure and shape integrity of the paper, being conducive to loading with catalytically active substances. Regarding the catalytic activity of MnO2-loaded LACFP, the concentration of formaldehyde decreased by 59 ± 6 ppm and the concentration of ΔCO2 increased by 75 ± 3 ppm when the reaction proceeded at room temperature for 10 h. The results indicated that MnO2-loaded LACFP could catalyze formaldehyde into non-toxic substances.

Identification and characterisation of heat shock protein gene (HSP70) family and its expression in Agave sisalana under heat stress

ABSTRACT Heat shock Protein (HSP) expression is the plants’ responses to high temperature. We analysed the HSP70 gene family in Agave sisalana transcriptome to understand its expression under heat stress. A total of 167 genes were identified as heat shock protein genes. Among them; 74, 39 and 25 belong to the HSP70, HSP20 HSP90 respectively and multiple sequence alignment of conserved domain proteins of AsHSP70 showed that they are highly conserved. Fifty-two AsHSPs were classified into three major classes according to their structural characteristics. Phylogenetic analysis indicated that orthologs from Agave deserti and Agave tequilana species were distributed among the three classes; which revealed the diverse expression of HSP70 gene family. In silico subcellular localisation of AsHSP, suggested that its interaction is quite diverse in target cells and active signalling pathways. Transcripts identified and named as B1, B3, B5, B7, B9, B11, B13, B15, B17 and B19 were validated through Nested PCR. Significant difference in the expression pattern of target gene was revealed after normalisation with GAPDH. Gene expression was up-regulated with some exceptions as down-regulated. In silico analysis of HSP70 gene family identified from A. sisalana suggests that genetic transformation of this gene will induce heat tolerance in transgenic crops.

Calm Before the Storm: A Glimpse into the Secondary Metabolism of Aspergillus welwitschiae, the Etiologic Agent of the Sisal Bole Rot.

Aspergillus welwitschiae is a species of the Nigri section of the genus Aspergillus. In nature, it is usually a saprotroph, decomposing plant material. However, it causes the bole rot disease of Agave sisalana (sisal), a plant species used for the extraction of hard natural fibers, causing great economic loss to this culture. In this study, we isolated and sequenced one genome of A. welwitschiae (isolate CCMB 674 (Collection of Cultures of Microorganisms of Bahia)) from the stem tissues of sisal and performed in silico and wet lab experimental strategies to describe its ability to produce mycotoxins. CCMB 674 possesses 64 secondary metabolite gene clusters (SMGCs) and, under normal conditions, it produces secondary metabolism compounds that could disturb the cellular cycle of sisal or induce abnormalities in plant growth, such as malformin C. This isolate also produces a pigment that might explain the characteristic red color of the affected tissues. Additionally, this isolate is defective for the production of fumonisin B1, and, despite bearing the full cluster for the synthesis of this compound, it did not produce ochratoxin A. Altogether, these results provide new information on possible strategies used by the fungi during the sisal bole rot, helping to better understand this disease and how to control it.

Culturable diazotrophic bacterial community associated with Agave sisalana P. plants from semi-arid regions in Brazil

The aim of this study was to isolate, quantify, identify and characterize the culturable diazotrophic bacterial community associated with sisal (Agave sisalana P.) and assess its potential for plant growth promotion and tolerance to abiotic stress. Nitrogen-free Burk’s medium was used for bacteria isolation and quantification. Isolates carrying the nifH gene were typed by BOX-PCR and sequenced for the 16S rRNA region. Additionally, the bacteria was tested for growth promotion in maize plants and for salinity tolerance in cucumber seedlings. The representative isolates were identified as members of Pantoea, Rhizobium, Burkholderia, Leifsonia and Bacillus genera. All isolates were positive for at least two of the nine plant growth promoting (PGP) traits tested. All isolates showed positive traits for tolerance to abiotic stress. Leifsonia sp. (S1.5) significantly increased root length, stem length and total fresh matter, and it was involved in the reduction of deleterious salt effects (60 mM NaCl) in cucumber seedlings. Diazotrophic bacterial community associated with sisal plants is genetically diverse, exhibits several plant growth-promoting traits and shows potential to support plant growth in adverse environments (salinity).

Penicillium citrinum as a Potential Biocontrol Agent for Sisal Bole Rot Disease

Agave sisalana, known as sisal, yields the world’s main natural stiff fiber used to produce various industrial products. The Brazilian semiarid is the largest sisal producing region in the world; however, production is under threat by sisal bole rot disease, caused by Aspergillus welwitschiae. Since chemical control of this disease is questionable in drought-ridden areas with little investment in crop management and due to environmental and public health concerns, the search for a biocontrol agent against A. welwitschiae is warranted. In this work, we isolated and identificated Penicillium citrinum as an endophyte from sisal plants collected from the Brazilian semi-arid and investigated whether it could be a biocontrol agent against sisal bole rot. P. citrinum inhibited the mycelium growth of A. welwitschiae by 65.8% when inoculated 72 hours before the pathogen, in dual culture medium assays. We found that P. citrinum can reduce sisal bole rot disease up to 90% when inoculated in sisal plants 48 hours before pathogen inoculation. Altogether, our data suggest a potential role for P. citrinum in the control of sisal bole rot disease.

Fabrication and Investigation on Impact, Hardness and Water Absorption Properties of Short Sisal and Glass fibre Reinforced Hybrid Thermoplastic Composites

Fabrication and Investigation on Impact, Hardness and Water Absorption Properties of Short Sisal and Glass fibre Reinforced Hybrid Thermoplastic Composites

Impact, Hardness and Water Absorption Properties of Natural Fibres (Banana, Hemp and Sisal) Hybrid Composite Material

Impact, Hardness and Water Absorption Properties of Natural Fibres (Banana, Hemp and Sisal) Hybrid Composite Material

Fabrication and Investigation on Tensile and Flexural Properties of Short Sisal and Glass fibre Reinforced Hybrid Thermoplastic Composites

Fabrication and Investigation on Tensile and Flexural Properties of Short Sisal and Glass fibre Reinforced Hybrid Thermoplastic Composites

Mechanical Properties of Short Natural Fibres (Banana, Hemp and Sisal) reinforced with Epoxy Hybrid Composite Material

Mechanical Properties of Short Natural Fibres (Banana, Hemp and Sisal) reinforced with Epoxy Hybrid Composite Material

Postharvest biocontrol of anthracnose in bananas by endophytic and soil rhizosphere bacteria associated with sisal (Agave sisalana) in Brazil

Banana is one of the most consumed fruits worldwide and a climacteric tropical commodity that requires harvesting methods, storage and transportation, which burden its marketing. It is one of the food crops most susceptible to diseases, such as anthracnose caused by Colletotrichum musae, considered the main postharvest disease of bananas. This pathogen is a quiescent fungus that infects the fruits during preharvest which symptoms appear at postharvest with advanced stage of maturity. Although efficient, the control using fungicides requires more than one pulverization. Therefore, this is unfeasible if one considers the time elapsed between harvesting and transportation of fruits, when symptoms are already visible. Furthermore, this control method has commercial and environmental restrictions which prevent this product of being certified as organic, which adds value to commodities. As an alternative to chemical control, biological control agents (BCAs) have been studied and used. In light of this information, we have selected 12 bacteria from in vitro tests, which are trivial for selecting biocontrol agents. In vivo testing, the following taxa were efficient in controlling the anthracnose: Bacillus velezensis, Enterobacter cloacae, Serratia marcescens and Stenotrophomonas maltophilia. B. velezensis showed similar performance as the Thiabendazole (Tecto SC®). Moreover, B. velezensis inhibited mycelial growth and pathogen sporulation and was positive for cellulase and xylanase activity, which are mechanisms of action relevant to a biocontrol agent. Furthermore, this bacterium can be considered as BCA of direct application by spraying and fruit immersion, or can be used systemically since B. velezensis is not pathogenic to humans.