Sisal Research Articles

In vitro Anthelmintic Efficacy of Medicinal Plants against Heterakis gallinarum in Village Chickens

<p><em>Heterakis gallinarum </em>impedes the productivity of village chickens and hence their socio-economic contribution to rural communties. Smallholder farmers are endowed with vast indigenous knowledge for controlling <em>H. gallinarum </em>and they predominantly use <em>Aloe ferox</em>, <em>Agave sisalan</em>a and <em>Gunnera perpensa</em>. However, their anthelminthic efficacy is unknown. Therefore, our objective was to determine the <em>in vitro</em> anthelmintic efficacy of <em>A. ferox</em>, <em>A. sisalana</em> and <em>G. perpensa</em> against <em>H. gallinarum</em>. <em>Heterakis gallinarum</em> worms were recovered from caeca of 20 village chickens. Ten worms were randomly introduced in each of the 42 petri-dishes. Treatments were positive control (distilled water), negative control (mebendazole) and <em>A. ferox</em>, <em>A. sisalana</em> and <em>G. perpensa</em> aqueous extracts at dosage of 7.25, 14.5, 29 and 58 mg/mL. The procedure was done in triplicate. Worm motility and mortality indices were calculated. Among plant, <em>A. sisalana</em> (14.5 mg/mL) had the greatest (80%) worm motility inhibition at 12-h interval (p < 0.05) and the greatest worm mortality index (80%) showing that the plant has anthelmintic properties. Seventy percent of worms were recovered after 48 h following treatment with <em>A. ferox</em> (58 mg/mL). <em>Agave sisalana</em> (14.5 mg/mL) was the most efficient plant in reducing motility and causing mortality of <em>H. gallinarum</em> <em>in vitro. </em>Findings are useful to resource-constrained farmers who use crude extracts, to select the best plant and to pharmaceutical companies for manufacturing anthelmintic drugs.</p>

Enzymatic surface modification of sisal fibers (Agave Sisalana) by Penicillium echinulatum cellulases

We report on the effect of a new microbial enzymatic system, Penicillium echinulatum cellulase, on the surface morphological (SEM), structural (XRD), and thermal (TGA/DTG) properties as well as the surface chemical composition (FT-IR and FT-Raman) of sisal fibers (Agave sisalana)—a potential replacement for glass fibers in composite materials. Cellulase treatment greatly improved the properties of sisal fibers, rendering the surface topography and chemical composition of the fibers free of contaminants and reducing the content of amorphous materials (hemicellulose, pectin, lignin, and disordered cellulose) to yield the crystalline cellulose network. Thermal stability and crystallinity were also greatly enhanced. This work demonstrated that microbial enzymes offer an inexpensive and environmentally attractive option to improve the surfaces of natural fibers for composite applications.

In vitro evaluation of the effect of aqueous extracts of Agave sisalana and Cymbopogon citratus on mycelial growth and conidia production of Pyricularia oryzae, causal agent of rice blast

Objectives: To evaluate the effects of aqueous extracts of Agave sisalana (sisal) and Cymbopogon citratus (lemon grass) on mycelial growth and conidia production of Pyricularia oryzae, causal agent of Rice Blast.Methodology and Results: The plants aqueous extracts were used at concentrations 0.1; 0.2; 0.3; 0.4; 0.5;1; 2; 3; 4; 5; 10; 20; 30% concentrations for Agave sisalana extracts and 0.5; 3; 5; 10; 15; 20% for C. citratus extracts. Fisher randomized block design with five (5) replicates was used to test the two extracts. All the two extracts tested had an inhibitory effect on the growth and spore production of the fungus. The Minimum inhibitory concentration (MIC) of Agave sisalana extracts was 3% (PI = 97%).For the C. citratus extract, the MIC was 20% and the concentration less than 20% had a mild effect on mycelial growth.Conclusion and application potential of the results: The use of pesticides of plant origin has been suggested by some researchers as alternatives to synthetic chemicals, in order to counter the potential hazards and pollution problems associated with the use of synthetic chemicals. The plants extracts tested showed antifungal activity. This result should enable use of aqueous extract of Agave sisalana to control blast diseases.Key words: In vitro, plant extracts, mycelial growth, spore production, rice blast, Pyricularia oryzae.

Cannot See the Flowers nor the Tree: Plants and the Pill.

The modern world suffers from a syndrome known as plant blindness—the inability to perceive plants.1 The lack of awareness occurs in the natural environment, the home landscape, and even the scientific lab. The third article in the inaugural issue of the American Chemical Society’s ACS Central Science(2) recognizes Carl Djerassi’s pioneering work in steroidal syntheses. However, the article belies the essential role that plant natural products played in one of the most significant technological achievements of the 20th century. The author the ACS Central Science article writes, “Scientists’ first attempts to create birth control pills focused on extracting progesterone from plants and animals. However, this approach failed to yield an effective oral medication.”2 There are three major flaws with these statements. First, progesterone’s insolubility in water and short half-life make it a poor candidate for oral contraceptives.3 Second, plants were not sources of progesterone, but rather sources of steroidal sapogenins that could be converted into progesterone and other steroids. Third, and the focus of this paper, Djerassi acknowledged the pioneering work of Russell Marker and the role plants played: “Marker ... made me focus on steroidal sapogenins [plant natural products] as starting materials for the synthesis of estrone and estradiol—steroid hormones that had not been part of his synthetic repertoire.”4 Marker had successfully produced progesterone from the sapogenins diosgenin and sarsasapogenin (Figure ​(Figure1),1), but none of the known plant sources yielded sufficient quantities of sapogenins to be cost-effective for industry. The intrepid chemist then began a search for better sapogenin sources which led to a Mexican species of yam (Dioscorea mexicana). Pharmaceutical companies spurned his discoveries, so Marker moved to Mexico and started Syntex, S.A. in 1944. His involvement with Syntex was short, and, following a quarrel with his partners, he soon left the company. Syntex floundered without Marker’s expertise and lab notes, until the company hired George Rosenkranz, who recruited Carl Djerassi and other talented chemists.5 After joining Syntex in 1949, Djerassi synthesized both cortisone and norethisterone, a progesterone mimic, from diosgenin extracted from Dioscorea mexicana.(6) Figure 1 Marker degradation, which converts plant sapogenins into medically important steroids. The role of plants in supplying the starting material for subsequent modifications is unquestioned and is noted by physicians, historians, and scientists, including Djerassi himself: “Interestingly, this genesis of estrogens ... led us in a fairly straight path to the first synthesis of an oral contraceptive in the same year (1951) in which we also announced the first synthesis of cortisone from a plant raw material—at that time arguably the hottest problem in synthetic organic chemistry.”4 Plants continued to play a vital role in the steroid industry after the initial euphoria of the 1940s and early 1950s. Another plant steroidal saponin, hecogenin, was first discovered in the terrestrial bromeliad Hechtia texensis (Bromeliaceae). It also occurs in the cultivated species sisal (Agave sisalana, Asparagaceae), which is the source of the fiber of the same name. Syntex pioneered the production of cortisone from sisal-derived hecogenin.7 The Mexican company licensed the process to Glaxo, which developed top selling drugs, including betamethasone and beclomethasone.3 Both have been on the World Health Organization’s list of essential medicines, and many other drugs on the list are either plant derived or based on chemical structures first identified in the botanical kingdom (e.g., artemether, Artemisia annua; etoposide and teniposide, Podophyllum peltatum). Chemists’ blindness toward plants stems from the term synthesis. When they describe the “synthesis” of a compound from or based on the structure of a natural product, they conceal the diversity of nature’s chemical palette and disregard the role of natural products. Plants continue to be the source of new lead compounds as well as new drugs. The work of many Nobel prize-winning chemists from Hermann Fischer’s sugar and purine syntheses (1902) to Elias Corey’s organic syntheses, including ginkgolides (1990), has been based, at least in part, on plant natural products. Let us not forget the importance of plants as sources of compounds for chemistry, medicine, and industry.

Abandoned Agave sisalana fiber crop plantation in the Negev Desert, Israel as source of firewood for local Bedouins

Firewood is a vital energy source for cooking and heating in traditional societies worldwide. During the past century, increasing human populations have depleted many previously available resources, resulting in severe shortages of firewood in many regions, especially in arid zones. Here, I describe the use as a source of firewood for a local semi-nomadic Bedouin village of several dozen families and the fate of a 0.3 km2abandoned fiber-crop plantation ofAgave sisalanaPerr. which is more than 50 years old in the Negev Desert, Israel. The amount of firewood extracted in the last decade equals several thousand local wild shrubs, which, in the current vegetation density, grow in a radius of several square kilometers. Harvesting the plantation for about 20 years almost fully exploited the plantation. Because the Bedouins do not replant plants used only for firewood, this source is not sustainable despite its biological potential to be so. However, becauseAgaveare CAM (Crassulacean acid metabolism) plants, they can grow under very arid conditions, and because they are well defended from grazing by thorns and poisons, they may be planted as a source of firewood in various arid regions where other plants will not sustain.

Chemicals from Agave sisalana Biomass: Isolation and Identification

Agave sisalana (sisal) is known worldwide as a source of hard fibers, and Brazil is the largest producer of sisal. Nonetheless, the process of removing the fibers of the sisal leaf generates 95% waste. In this study, we applied chemical sequential steps (hydrothermal extraction, precipitation, liquid-liquid extraction, crystallization, SiO2 and Sephadex LH 20 column chromatography) to obtain pectin, mannitol, succinic acid, kaempferol and a mixture of saponins as raw chemicals from sisal biomass. The structural identification of these compounds was performed though spectrometric methods, such as Infrared (IR), Ultraviolet (UV), Mass spectrometry (MS) and Nuclear magnetic resonance (NMR). All the sisal chemicals found in this work are used by both the chemical and pharmaceutical industries as excipients or active principles in products.

Potential use of the liquor from sisal pulp hydrolysis as substrate for surfactin production

Surface-active compounds of microbial origin are more environmentally-friendly, biocompatible and biodegradable when compared with synthetic surfactants therefore, the market interest in such molecules is increasing; however, their production costs are not competitive to chemical surfactants. The use of low-cost substrates such cellulosic-based material is a strategy to reduce economics of biosurfactant (BS) production and also contribute to reducing greenhouse gas emissions. The aim of this work was to evaluate the potential application of the liquor obtained from sisal (Agave sisalana) pulp hydrolysis as substrate for biosurfactant production. The liquor deriving from acid and enzymatic hydrolysis of sisal cellulose was utilized as carbon source to provide growth and surfactin production by a Bacillus subtilis strain. The surfactin obtained in acid hydrolysate showed a surface tension (ST) of 29.8mNm−1, interfacial tension (IT) of 5.7mNm−1 and a critical micelle concentration (CMC) of 1394.0mgL−1, whereas when enzymatic hydrolysate was utilized the product showed a ST of 28.7mNm−1, IT of 3.8mNm−1 and a CMC of 64.0mgL−1. The washing of contaminated sand with surfactin obtained in acid and enzymatic hydrolysate removed 80% and 70% of diesel, respectively, suggesting good potential for bioremediation. Mass spectrometry analysis showed that the surfactin obtained from EH has homologous molecules distribution similar to standard product. The results suggest that the liquor from sisal pulp hydrolysis is a feasible and sustainable substrate for surfactin production.

High-resolution GPS tracking reveals habitat selection and the potential for long-distance seed dispersal by Madagascan flying foxes Pteropus rufus

Long-distance seed dispersal can be important for the regeneration of forested habitats, especially in regions where deforestation has been severe. Old World fruit bats (Pteropodidae) have considerable potential for long-distance seed dispersal. We studied the movement patterns and feeding behaviour of the endemic Madagascan flying fox Pteropus rufus, in Berenty Reserve, southeast Madagascar. Between July and September 2012 (the dry season) nine males and six females were tagged with customised GPS loggers which recorded fixes every 2.5 min between 18.00 and 06.00 h. The combined home range of all of the tagged bats during 86 nights exceeded 58,000 ha. Females had larger home ranges and core foraging areas and foraged over longer distances (average 28.1 km; median 26.7 km) than males (average 15.4 km; median 9.5 km). Because the study was conducted during the gestation period, the increased energy requirements of females may explain their greater mean foraging area. Compositional analysis revealed that bats show strong preferences for overgrown sisal (Agave sisalana) plantations (a mix of shrub, trees and sisal plants) and remnant riverside forest patches. Sisal nectar and pollen were abundant food sources during the tracking period and this probably contributed to the selective use of overgrown sisal plantations. The bats also ate large quantities of figs (Ficus grevei) during the study, and dispersed seeds of this important pioneer species. The bats flew at an average speed of 9.13 m/s, perhaps to optimise gliding performance. The study confirms that P. rufus has the potential to be a long-distance seed disperser, and is able to fly over a large area, often crossing cleared parts of its habitat. It potentially plays an important role in the regeneration of threatened forest habitats in this biodiversity hotspot.

Control of the banana burrowing nematode using sisal extract

The nematode Radopholus similis is a major pest in banana plantations worldwide. This nematode is actually controlled using synthetic, toxic nematicides. Alternative control methods are therefore needed. For instance the liquid by-product of fiber extraction from sisal (Agave sisalana) may be used as a nematicide. Here we tested the nematicidal activity of the sisal residue, fresh or fermented, on R. similis in banana plants. We measured immobility and mortality effects by nematode immersion in an aqueous solution of sisal residue for 24 and 48 h. Nematode control was also evaluated in the Grand Naine banana plants under greenhouse conditions using soil amendments of residues. We measured plant growth, pseudostem diameter, the number of leaves, and the dry weight of the aerial parts, corm and roots, as well as factors related to nematode control such as the level of damage, the population of R. similis in roots and soil, and nematode reproduction factors. Our results show that the sisal residue efficiently controlled R. similis in vitro, displaying mortality rates of 99.2 % for the fresh residue. The damage caused by R. similis on plants was similar for the treatment with the sisal residue at a concentration of 25 % and with the nematicide. This is the first report on the nematicidal effect of the sisal liquid residue on the banana burrowing nematode. This by-product presents the potential for the development of new alternatives for nematode control, with a low-cost and low-environmental risk plant nematicide.

Effect of Medicinal Plants on Haematology and Serum Biochemical Parameters of Village Chickens Naturally Infected with <i>Heterakis gallinarum</i>

The effects of Aloe ferox, Agave sisalana and Gunnera perpensa on haematological and biochemical parameters of village chickens naturally infected with Heterakis gallinarum were evaluated. One hundred and twelve mature village chickens were randomly allotted into 14 groups of 8 chickens. Group 1 and 2 were orally administered 1 mL distilled water for 4 consecutive days and 1 mL mebendazole (once), respectively. Groups 3-6 received 1 mL orally of aqueous leaf extract of A. ferox for 4 consecutive days, groups 7-10 A. sisalana and 11-14 G. perpensa in graded doses of 50, 100, 200 and 400 mg/kg, respectively. Blood was collected into vacutainers in triplicate, from the wing veins on day 0, 7 and 14. Data was analysed using general linear model of statistical analyses system. Chickens offered A. sisalana (200 mg/kg) had highest alanine transaminase (ALT) value (P < 0.05; 7.50 ± 0.406 U/l) on day 0. On day 7 and 14, there was no difference in ALT values (P >0.05). Significant differences among plants for aspartate transaminase on day 0, 7 and 14 were observed. Mean corpuscular haemoglobin concentration and mean corpuscular volume were maintained within the reference range. From day 0 to 14, haematocrit was reduced for chickens on G. perpensa (50, 100 and 400 mg/kg), A. ferox (100 and 400 mg/kg) and A. sisalana (50, 100, 200 and 400 mg/kg). Haemoglobin was out of range on day 0 and improved to be within the range on day 7 and 14. The medicinal plants enabled normal synthesis and functioning of haematological and biochemical parameters of village chickens and were maintained within the expected reference ranges. These plants are crucial phytomedicines for treating H. gallinarum infestations in village chickens.DOI: http://dx.doi.org/10.3329/bjvm.v12i2.21263Bangl. J. Vet. Med. (2014). 12 (2): 99-106

The larvicidal activity of Agave sisalana against L4 larvae of Aedes aegypti is mediated by internal necrosis and inhibition of nitric oxide production.

Dengue is a viral disease that affects about 50 million people per year around the world. The aim of this study was to investigate the larvicidal activity of Agave sisalana crude extract in order to develop a new insecticide against Aedes aegypti. In larvicidal activity assays, fourth-stage Ae. aegypti larvae were exposed to different concentrations of A. sisalana crude extract for 3, 6, 12, and 24 h for determining the LC50. Next, we explored its cytotoxic activity by flow cytometry. Furthermore, histological alterations were confirmed by histopathological analysis, and the nitric oxide (NO) production by hemocytes was checked after different periods of exposure to A. sisalana crude extract. The LC50 was 4.5 ± 0.07 mg/mL. In addition, flow cytometry revealed an increase of cellular necrosis (21 and 16.5 % after 12 and 24 h, respectively) in larvae that were exposed to A. sisalana crude extract. The histological analysis revealed cell lysis and destruction of the peritrophic membrane. Furthermore, there was a reduction in the concentration of NO in the hemolymph from larvae exposed to A. sisalana crude extract after 3, 6, and 24 h (5.3 ± 4.3 vs. 22.7 ± 5.2 μM, 4.3 ± 5.5 vs. 25.4 ± 6.6 μM, and 6 ± 1.7 vs. 37.1 ± 7.8 μM, respectively). Our findings show that A. sisalana crude extract constitutes an effective larvicidal agent against Ae. aegypti larvae due to its necrotizing activity in hemocytes and inhibition of the NO production.

Biotransformation of steroidal saponins in sisal (Agave sisalana Perrine) to tigogenin by a newly isolated strain from a karst area of Guilin, China

A rod-shaped bacterium was isolated from the soil in a karst area of Guilin, China and its biotransformation of steroidal saponins in sisal (Agave sisalana Perrine) to tigogenin was presented for the first time. A total of 22 strains for the degradation of steroidal saponins in sisal were isolated from 48 soil samples, and the isolated rod-shaped, bacterial strain ZG-21 was used for the production of tigogenin due to its highest degradation efficiency of steroidal saponins in sisal. The parameters affecting biotransformation by strain ZG-21 were optimized. Under the optimized conditions of temperature (30 °C), pH (6), time (5 days) and substrate concentration (5 mg/mL), a maximum tigogenin yield of 26.7 mg/g was achieved. Compared with the conventional method of acid hydrolysis, the biotransformation method provided a clean and eco-friendly alternative for the production of tigogenin.

Homeopathic drugs to control red rot disease in sisal plants

Sisal—Agave sisalana Perrine ex. Engelm—is a key economical and social crop in the semi-arid region of Brazil, especially in the Bahia state. Sisal is severely affected by Aspergillus niger Thieg, the causal agent of sisal red rot. Currently, existing control strategies are fruitless. Here, we tested different homeopathic drugs Carbo vegetabilis, Ferrum metallicum, Natrum muriaticum, phosphorus and sulphur at centesimal Hahnemannian (CH) dynamizations, of 3CH, 5CH, 7CH, 9CH and 12CH, on Aspergillus niger. We measured in vitro growth inhibition, sporulation and germination of Aspergillus niger during 12 days. We assessed in planta Aspergillus niger incidence and disease severity. Our results show that homeopathic drugs inhibited Aspergillus niger growth in vitro, in a dynamization-dependent way. Natrum muriaticum 5CH revealed the higher inhibition of 66 %, whereas sulphur 5CH yielded the lowest inhibition of 6.4 %. Spore production was stimulated using all homeopathic drugs at all dynamization levels, whereas spore germination was reduced. In planta assays revealed different results from in vitro assays, corroborating that in planta and in vitro effectiveness is different according to the homeopathic drugs applied. Here, disease incidence was not reduced significantly, but disease severity was lower in treated plants, of 27.8 % using Ferrum metallicum 9CH than in control trials, of 73.6 %. Overall, our findings suggest that homeopathic drugs could be a good strategy to control Aspergillus niger incidence in sisal plants.

In vivo anthelmintic efficacy of Aloe ferox, Agave sisalana, and Gunnera perpensa in village chickens naturally infected with Heterakis gallinarum

The study was conducted to determine the anthelmintic efficacy of Aloe ferox, Agave sisalana, and Gunnera perpensa against Heterakis gallinarum in village chickens. The chickens naturally infected with H. gallinarum were randomly divided into 14 groups of eight chickens and orally administered distilled water (negative control), mebendazole (positive control), and graded levels (50-, 100-, 200-, and 400-mg/kg doses) of the three plant extracts. At days 0, 7, and 14, the floatation technique was used to determine fecal egg counts and H. gallinarum worms from chicken ceca were counted at days 0 and 14. Egg count reduction percentage (ECR%) was high at day 7 for all the test materials except for A. sisalana (100 mg/kg) that had 33%. At day 14, ECR% was high for all the other test materials save for A. ferox (200 mg/kg), mebendazole, and distilled water which was 50, 32, and 50%, respectively. A. ferox (200 mg/kg), G. perpensa (200 and 400 mg/kg), and A. sisalana (50 and 100 mg/kg) had the highest (85, 78, 74, 86, and 73%, respectively) worm count reduction percentage. The plants had anthelmintic properties. Advocacy and utilization of these plants in improving the health of village chickens could lead to increased productivity, boosting profits for the poultry industry thereby enabling it to meet the supply of animal protein and enhance livelihoods. It is imperative to determine compounds in the crude extracts of these medicinal plants which are responsible for the anthelmintic activities and their mechanism of action.

Larvicidal activity of Agave sisalana against Aedes aegypti mosquito, the dengue vector

Background Dengue is a viral systemic disease caused by an arboviral of Flaviviridae family, affecting about a 700 thousand cases per year in Brazil. It is endemic in tropical regions such as Southeast Asia, South Pacific, East Africa, Caribbean and Latin America. The disease is transmitted by Aedes aegypti (Linnaeus, 1762), a mosquito that is the main target for the disease control through strategies ranging from the larval to the adult combat. The larvicides commonly used to combat the vector, besides being toxic, present drop in larvicide efficacy since the A. aegypti larvae has developed resistance to these products. Thus, the search for new active principles that are effective in combating the mosquito is required. In this sense, Agave sisalana is a plant that is produced in several states in the Brazilian northeast region, which is used in the sisal industry. Only 5% of the plant is recovered, and its residual liquid completely wasted. In this way, the aim of this research project was to investigate the larvicidal action of the juice of Agave sisalana against larvae of A. aegypti.

Cytotoxicity of Agave sisalana in hemocytes of the mosquito Aedes aegypti, which transmits dengue

Background The dengue is a viral disease transmitted by a mosquito from the Culicidae family from Africa, the Aedes aegypti. Most common in tropical and subtropical regions, this mosquito has diurnal activity and is difficult to control due to the high resistance of its eggs and its quick transformation into larvae. The severe illness may cause death, most commonly presenting symptoms such as high fever, pain behind the eyes and headaches.

Seed treatment with an aqueous extract of Agave sisalana improves seed health and seedling growth of sorghum

An aqueous extract of the sisal agave, A. sisalana, was prepared from dried stem tissue by boiling in water. The sisal extract (SE) displayed a broad inhibition of the seed-borne mycoflora when applied to farmer-saved seeds of Sorghum bicolor. Species of Fusarium (belonging to the Gibberella fujikuroi complex) were inhibited >75 % on seeds. Accordingly, seed-borne crown rot, associated with Fusarium thapsinum was significantly (p < 10−7) and dose-dependently reduced in plants from SE treated seeds. The SE treatment furthermore stimulated seedling vigour and increased dry weight of 4-week-old plants (p < 10−4) with 35 %. The growth promoting activity of SE was found to be similar to what has been reported for the extract of another agave, Yucca schidigera. Both extracts were found to reduce seed-borne Fusarium and crown rot more efficiently than fungicides based on tebuconazole, enilconazole and fludioxonil (p < 0.0042). The stem of the sisal agave is a waste product in fiber production. From our findings A. sisalana stem appears to represent an abundant source of antifungal activity, simple to extract, easy to store and with a promising potential in biological seed treatment.

Diazotrophic bacteria associated with sisal (Agave sisalana Perrine ex Engelm): potential for plant growth promotion

In the semi-arid region of Bahia State, Brazil, sisal (Agave sisalana Perrine ex Engelm) has been cultivated for fibre production for several decades without the use of chemical fertilizers. The contribution of biological nitrogen fixation (BNF) to this crop and the occurrence of diazotrophic rhizosphere, epiphytic or endophytic bacteria have not been investigated. The aims of this work were to study the occurrence and diversity of diazotrophic bacteria in rhizosphere soil, root and leaf tissues of sisal plants from this region, as well as to test their potential for plant growth promotion. Burk’s nitrogen free semi-solid medium was used for isolation and the MPN method was used for quantification of diazotrophic bacteria. BOX-A1R PCR and 16S rRNA sequence analyses were performed to study the diversity of bacterial isolates harboring the nifH-gene. Six isolates were selected for growth promotion of cucumber plants. A high diversity of BNF bacterial isolates was observed in sisal plants and rhizosphere soil. Bacterial populations were higher in roots, followed by soil and sisal leaves. Burkholderia, Leifsonia and Paenibacillus were the predominant genera. All isolates tested were able to promote cucumber growth. This study showed that sisal-associated diazotrophic bacteria are diverse and may be further exploited to promote plant growth.

Additional species of Aspergillus causing bole rot disease in Agave sisalana

The production of sisal in Bahia, Brazil, has been declining due to the occurrence of a disease know as bole rot. Aspergillus niger was regarded as the only causal agent. In this study A. brasiliensis and A. tubingensis, in addition to Aspergillus niger, identified on the basis of morphological and molecular analyses, were shown to cause bole rot of sisal. Their pathogenicity was confirmed but their significance for the epidemiology of the disease in the field remains unclear.

Use of micellar extraction and cloud point preconcentration for valorization of saponins from sisal (Agave sisalana) waste

Sisal (Agave sisalana) is the main hard fiber produced worldwide, with an estimated generation of 400 thousands t in 2011. From its leaves, only the hard fibers, which represent 3–5% of their weight, are removed. The remaining 95–97% is referred to as sisal waste and contains steroidal saponins that can be potentially used in foods, cosmetics and pharmaceuticals formulations, as well as for soil bioremediation. The present work aimed at to evaluate strategies for the extraction and concentration of saponins from sisal waste, focused on the use of clean solvents, such as water and ethanol. For this purpose, it was firstly performed a central composite rotatable design for the optimization of the extraction conditions followed by a comparison of this strategy with other methods (Soxhlet, ultrasound-assisted extraction and micellar extraction). Cloud point preconcentration was then tested, using several types and concentrations of salts. The use of orbital shaker extraction (200rpm) with an ethanolic solution (30%, v/v) at 50°C, a mass/volume ratio sisal/solvent of 0.17 (g/mL) for 4h allowed a recovery of 38.6% of the saponins. When a micellar extraction strategy using 7.5% (v/v) of Triton X-100, under the above-mentioned conditions was performed, saponins recovery raised to 98.4%. In a subsequent step, the addition of 20% (m/v) sodium carbonate led to a preconcentration factor of 20.3. The best adsorbent for Triton removal from the preconcentrated solution was Amberlite FPX-66. The process strategy proposed in the present study showed to be efficient for saponins extraction and preconcentration from a low-cost, highly available agricultural waste.