Effects of washing, milling and loading enzymes on the enzymatic hydrolysis of a steam pretreated sugarcane bagasse

Enzymatic hydrolysis of steam pretreated sugarcane bagasse was performed to investigate the production of glucose and xylose. A blend of industrial enzymes (Novozymes) was used. The enzymes were used either without having been washed or having been washed with water or 1% aqueous NaOH solution. The influence of the size of sugarcane bagasse and the proportion of the enzymatic cocktail, which was composed of endoglucanases/cellobiohydrolases (Celluclast 1.5L) and β-glucosidase (Novozym 188) cellulases mixtures, was investigated. The tests were performed at a temperature of 50 °C and at a pH of 4.8 during a period of 72 h. The assays that were conducted with a pretreated sugarcane bagasse that was washed with a 1% aqueous NaOH solution without milling led to the largest amounts of glucose after 72 h, which was independent of the proportions of enzymes used in experiments with the smallest amounts of enzymes. The largest amount of xylose was obtained with a pretreated sugarcane bagasse that was not washed.     

Cornstarch and tannin in phenol–formaldehyde resins for plywood production

The aim of this work is to demonstrate the performances of cornstarch–quebracho tannin-based resins designed as adhesive in the plywood production. In this way, the cornstarch and quebracho tannin was introduced in the classic adhesive formulation in order to supply a part of phenol–formaldehyde (PF). The physical properties (rheological characterization, thermogravimetric analysis and solid phase ¹³C NMR analysis) of the formulated resins were measured. In order to evaluate the mechanical performances of optimal cornstarch–quebracho tannin-based resins, plywood panels were produced and mechanical properties were investigated. These mechanical properties included tensile strength, wood failure and 3-point bending strength. The performance of these panels is comparable to those of plywood panels commercial PF made.The results showed that plywood panels bonded with cornstarch–quebracho tannin–PF resins (15:5:80, w/w/w) exhibited better mechanical properties than plywood panels commercial PF made. The introduction of small proportions of cornstarch and quebracho tannin in PF resins contributes to the improvement of the boiling water performance of these adhesives. The formaldehyde emission levels obtained from panels bonded with cornstarch–quebracho tannin–PF were lower to those obtained from panels bonded with control PF. Solid state CPMAS NMR spectra indicates that no reaction at all between PF resins and cornstarch and quebracho tannin. Even when reaction does evidently not occur, the addition of cornstarch and quebracho tannin improves markedly the water resistance of PF resins.     

Steam explosion pretreatment reproduction and alkaline delignification reactions performed on a pilot scale with sugarcane bagasse for bioethanol production

This work was focused on the steam explosion pretreatment reproduction and alkaline delignification reactions on a pilot scale for the ethanol production, through different varieties of natural sugarcane bagasse, pretreated bagasse and delignified pretreated bagasse (cellulosic pulp). The possible chemical composition differences of the various types of bagasse, as well as the chemical composition variations of the materials in the 20 processes of pretreatment and delignification on the pilot scale were verified. The analytical results of the 20 samples of most diverse varieties and origins of natural sugarcane bagasse considering planting soils, planting periods and weather; show no significant chemical differences. It is evident that only with the chemical composition it is not possible to verify the differences between the varieties of sugarcane bagasses. The research results may offer some evidences of these varieties, but it is not a reliable parameter. The pilot process of steam explosion pretreatment and the alkaline delignification process of pretreated material showed through analytical results a good capacity of reproduction, as the standard differences were below 2.7. The average allowed in the pretreatment and alkaline delignification processes were 66.1 ± 0.8 and 51.5 ± 2.6 respectively, ensuring an excellent reproduction capacity of the processes obtained through chemical characterizations.     

Arundo donax chipboard based on urea-formaldehyde resin using under 4 mm particles size meets the standard criteria for indoor use

Common reed (Arundo donax) is a fast growing perennial plant, considered in many countries as a weed or invasive plant. New material developments in recent years have led to common cane proliferation and an invasion in crops and water channels, significantly increasing elimination and control costs. In this study, it is proposed that particleboard be manufactured of common reed (A. donax). The objective is twofold. On the one hand it allows control of a weed, and secondly, it helps reduce the high dependence of imported wood timber and boards by using a readily and annually renewable resource.The fibers of common reed A. donax, possess high tensile strength (200 N/mm² between knots), providing much higher values than wood. This fact together with an important moisture and aging resistance, encourage us to propose it as a suitable raw material for the production of particleboards. In this study we propose the manufacture of particle board with urea formaldehyde resin, which is currently used in the wood chipboard industry.To perform this study, A. donax fibers obtained from a shredding hammer, were classified attending to size and slenderness. Following the standard industrial chipboard manufacturing processes, boards were developed to compare their behaviour against wood chipboards. Fifteen test-tube batches with different proportions of pre-selected fibers were manufactured. New boards were subjected to a mechanical stress test, and other physical properties were also measured. UNE EN—specific wood chipboard regulations were applied.Results showed that particleboard could be manufactured using A. donax adjusting the particle size to a maximum of 4 mm sieves. Finally it can be stated that making common reed panels also involves the reuse of a plant actually considered a weed, to become a raw material for industrial applications, leaving a door open to future development and research areas.     

Composite materials of thermoplastic starch and fibers from the ethanol-water fractionation of bagasse

The aim of this study was to evaluate the potential of the fibrous material obtained from ethanol-water fractionation of bagasse as reinforcement of thermoplastic starches in order to improve their mechanical properties. The composites were elaborated using matrices of corn and cassava starches plasticized with 30 wt% glycerin. The mixtures (0, 5, 10 and 15 wt% bagasse fiber) were elaborated in a rheometer at 150 °C. The mixtures obtained were pressed on a hot plate press at 155 °C. The test specimens were obtained according to ASTM D638. Tensile tests, moisture absorption tests for 24 days (20-23 °C and 53% RH, ASTM E104), and dynamic-mechanical analyses (DMA) in tensile mode were carried out. Images by scanning electron microscopy (SEM) and X-ray diffraction were obtained. Fibers (10 wt% bagasse fiber) increased tensile strength by 44% and 47% compared to corn and cassava starches, respectively. The reinforcement (15 wt% bagasse fiber) increased more than fourfold the elastic modulus on starch matrices. The storage modulus at 30 °C (E_30 °C′) increased as the bagasse fiber content increased, following the trend of tensile elastic modulus. The results indicate that these fibers have potential applications in the development of biodegradable composite materials.     

Sugarcane bagasse whiskers: Extraction and characterizations

This work evaluates the use of sugarcane bagasse (SCB) as a source of cellulose to obtain whiskers. These fibers were extracted after SCB underwent alkaline peroxide pre-treatment followed by acid hydrolysis at 45 °C. The influence of extraction time (30 and 75 min) on the properties of the nanofibers was investigated. Sugarcane bagasse whiskers (SCBW) were analyzed by transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) in air atmosphere. The results showed that SCB could be used as source to obtain cellulose whiskers and they had needle-like structures with an average length (L) of 255 ± 55 nm and diameter (D) of 4 ± 2 nm, giving an aspect ratio (L/D) around 64. More drastic hydrolysis conditions (75 min) resulted in less thermally stable whiskers and caused some damage on the crystal structure of the cellulose as observed by XRD analysis.     

Utilization of pretreated bagasse for the sustainable bioproduction of cellulase by Aspergillus nidulans MTCC344 using response surface methodology

Response surface methodology (RSM) was used to optimize the conditions for the production of endo β-1,4 glucanase, a component of cellulase by Aspergillus nidulans MTCC344 under solid state fermentation, using bagasse as the chief substrate. A four-factor-five-level central composite design was employed for experimental design and analysis of the results. Maximum cellulase activity (CMCase was 28.96 U g⁻¹) can be attained at the optimum conditions, 16.8 mm bagasse bed height, 60% moisture content, pH 4.25 and temperature 40 °C in the solid state fermenter. These data were rather close to the experimental results obtained (CMCase was 28.84 U g⁻¹). A. nidulans MTCC344 was able to hydrolyze pretreated bagasse completely after 8 days of incubation with significant endo β-1,4 glucanase activities. The results of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) of bagasse showed structural changes through pretreatment, in favor of enzymatic hydrolysis. Bagasse with alkali pretreatment using sodium hydroxide is a source of lignocelluloses able to improve the yield of endo β-1,4 glucanase by the strain of A. nidulans. The endo β-1,4 glucanase produced during the bioconversion of cellulose to glucose by A. nidulans MTCC344 is strongly dependent on the pretreatment given before hydrolysis.     

Optimization of ethanol production by Saccharomyces cerevisiae UFPEDA 1238 in simultaneous saccharification and fermentation of delignified sugarcane bagasse

Ethanol production by Saccharomyces cerevisiae UFPEDA1238 was performed in simultaneous saccharification and fermentation of delignified sugarcane bagasse. Temperature (32 °C, 37 °C), agitation (80; 100 rpm), enzymatic load (20 FPU/g cellulose and 10%, v/v β-glucosidase or 10 FPU/g cellulose and 5% β-glucosidase) and composition of culture medium were evaluated. Ethanol concentration, enzymatic convertibility of cellulose and volumetric productivity were higher than 25 g/L, 72% and 0.70 g/L h, respectively, after 30 h, when the culture medium 1 and 20 FPU/g cellulose/10%, v/v β-glucosidase or the culture medium 2 and 10 FPU/g cellulose/5% β-glucosidase were used in SSF at 37 °C and 80 rpm. In the SSF with culture medium 2 (supplemented with ammonium, phosphate, potassium and magnesium), 150 L ethanol/t bagasse was achieved, with minimum enzyme loading (10 FPU/g cellulose and 5%, v/v β-glucosidase) for 8%, w/v of solids, which is often an important requirement to provide cost-efficient second generation ethanol processes.     

Effect of outdoor exposure on some properties of resin-treated plybamboo

The objective of this investigation was to evaluate some of the physical and mechanical properties of resin-treated plywood type panels manufactured from bamboo strips (Gigantochloa scortechinii). Experimental plybamboo samples were made from low molecular weight phenol formaldehyde (LMwPF) treated bamboo strips. They were exposed to outdoor condition ranging from 1 to 12 months. Modulus of elasticity (MOE), modulus of rupture (MOR), compression strength, and surface roughness of treated and untreated samples were evaluated. Resin impregnated samples had the highest bending and compression strength properties. While the untreated samples failed after 3-month of outdoor exposure. Treated specimens exposed for 12-month had the MOE, MOR, and compression strength values of 14,253 N/mm², 101.3 N/mm², and 34.63 N/mm², respectively. Surface quality of both treated and untreated samples was adversely influenced as the function of outdoor exposure time, based on numerical values obtained from a stylus type equipment. Overall properties of treated samples tested in work resulted in higher values than those of untreated samples. It appears that resin impregnation could be considered as an alternative method to enhance the characteristics of plybamboo exposed to environmental conditions as can be concluded from the results of this study.     

Production of activated carbon from organic by-products from the alcoholic beverage industry: Surface area and hardness optimization by using the response surface methodology

The ability of activated carbon to remove pollutants from water in packed column systems is dependent on granular material with mechanical strength sufficient to avoid attrition caused by stream flow. Therefore, an appropriate balance between surface area and hardness is essential when using activated carbon in real systems. The purpose of this research is to determine the optimal production conditions that generate activated carbon with adequate physical properties to be used in packed systems from agave bagasse, a waste product from the mezcal industries in Mexico. Activated carbons were produced by chemical activation (ZnCl₂ or H₃PO₄). Response surface methodology (RSM) was used to evaluate the effect of the activation temperature (250-550 °C), activation time (0-50 min), and the concentration of activating agent (0.2-1.4; g activating agent/g bagasse) on both surface area and hardness. The production conditions that generated optimal characteristics in the activated carbon were 392 °C, 1.02 g activating agent/g bagasse and 23.8 min for H₃PO₄ activated samples and 456 °C, 1.08 g activating agent/g bagasse and 23.8 min for ZnCl₂ activated samples. The surface area and hardness of the activated carbon produced from bagasse under these conditions were similar to activated commercial carbons (surface area > 800 m²/g and hardness > 85%).     

Release of doxycycline through cellulose acetate symmetric and asymmetric membranes produced from recycled agroindustrial residue: Sugarcane bagasse

Cellulose acetate is one of the components employed in drug controlled-release systems in the form of membranes. The aim of this study was to examine the controlled-release of doxycycline employing cellulose acetate symmetric and asymmetric membranes as matrices. The cellulose triacetate was produced from sugarcane bagasse through a homogeneous acetylation reaction, using acetic acid as the solvent, acetic anhydride as the acetylating agent and sulfuric acid as the catalyst. The viscosity average molecular weight of the cellulose acetate produced was 39,000 g mol⁻¹. The symmetric membranes were produced using a system solvent of dichloromethane/ethanol (9:1, v/v) and the asymmetric membranes were produced from the same solvent system and 10% of water. For the formulation of both, 5% of doxycycline was used. The membranes were characterized by thermal analysis (DSC and TGA) and scanning electron microscopy SEM. The release of doxycycline through cellulose triacetate matrices was examined using spectrophotometric analysis in the ultraviolet-visible region, at 275 nm. The results revealed that asymmetric membranes release 80% of the drug in 100 min, while symmetric membranes release 14% of the drug during the same time interval.     

Bioethanol production from sweet sorghum bagasse by Mucor hiemalis

The present work deals with production of ethanol from sweet sorghum bagasse by a zygomycetes fungus Mucor hiemalis. The bagasse was treated with phosphoric acid and sodium hydroxide, with or without ultrasonication, prior to enzymatic hydrolysis by commercial cellulase and β-glucosidase enzymes. The phosphoric acid pretreatment was performed at 50 °C for 30 min, while the alkali treatment performed with 12% NaOH at 0 °C for 3 h. The pretreatments resulted in improving the subsequent enzymatic hydrolysis to 79-92% of the theoretical yield. The best hydrolysis performance was obtained after pretreatment by NaOH assisted with ultrasonication. The fungus showed promising results in fermentation of the hydrolyzates. In the best case, the hydrolyzate of NaOH-ultrasound pretreated bagasse followed by 24 h fermentation resulted in about 81% of the corresponding theoretical ethanol yield. Furthermore, the highest volumetric ethanol productivity was observed in the hydrolyzates of NaOH pretreated bagasse, especially after ultrasonication in pretreatment stage.     

Comparative analysis of physiological characteristics and yield components in sugarcane cultivars

Sugarcane in an important crop due to the economic value of its products. Physiological characteristics and yield components of sugarcane were studied in three field-grown sugarcane cultivars B 63118, POJ 2878 and Ja 60-5. Three growth stages were identified: formative phase (until 140 DAP), grand growth (140–300 DAP) and maturity (after 300 DAP). Results indicated that cultivars showed contrasting yield mainly after 300 DAP. At ripening, the most productive cultivar (Ja 60-5) achieved higher leaf area, an optimum leaf area index for light interception, a high and stable net assimilation rate and an elevated leaf area and biomass duration. In addition, this cultivar showed the higher density and lower area of leaf sieve elements as compared with other, which could influence the high translocation rate (1.85 cm min⁻¹) at 8 MAP. The higher efficiency of this process in Ja 60-5 might also be supported by a higher (15–25%) apparent free space of stem parenchyma as compared with POJ 2878 and B 63118. Our results suggest that Ja 60-5 reduced carbon partitioned to foliar respiration which led to a higher partitioning of sucrose to stems evidenced by a higher Pol%.     

Developing lignin-based resin coatings and composites

Phenol in phenol formaldehyde (PF) resin has been partly substituted with lignin extracted from sugarcane bagasse. In order to optimize the lignin-based resin for applications in coating and composite materials, thermal and rheological tests were performed with different wt% of lignin substitution into PF resins. Differential scanning calorimetry scans showed a small exothermic peak and a large endothermic peak, typical of resins. The T_g of the resins was seen between 125 and 150 °C and this transition was clearly evident when the lignin content was increased from 10 to 40 wt%. Increasing the lignin content in the PF resin increases the rate of cure and the heat of reaction. Water absorption tests show that the lignin-PF resin films are effective water-barrier coatings for cardboard substrates. It is speculated that the interaction between the substrate and the lignin-PF resin has resulted in a negative surface charge which would have contributed to the reduction in the contact angle.     

Photocatalytic degradation of formaldehyde by silk mask paper loading nanometer titanium dioxide

Silk mask paper with different adsorbability was prepared by changing the beating degree of silk pulp and the basis weight of silk paper, and photocatalytic silk mask paper was prepared by loading nanometer titanium dioxide (nano-TiO₂) on the silk mask paper, then degradation of formaldehyde by silk mask paper loading nano-TiO₂ under daylight lamps and ultraviolet lamps were investigated, respectively. Results showed that silk mask paper could adsorb formaldehyde and had higher adsorption efficiency in the initial stage, and the adsorption/desorption equilibrium could be basically achieved in 60 minutes. The adsorption capacity of silk mask paper made from silk pulp with beating degree of 45 ^oSR was relatively low, and it increased with the increase of beating degree, but there was little change in adsorption when the beating degree of silk pulp exceeded 65 ^oSR. Under daylight lamps, 26.61 %, 31.42 % and 38.21 % of formaldehyde could be degraded in 180 minutes by silk mask paper loading 1 wt%, 3 wt% and 5 wt% nano-TiO₂, respectively. However, under ultraviolet (UV) lamps, 46.23 %, 55.47 % and 66.38 % of formaldehyde could be degraded within the same time, respectively. More formaldehyde could be degraded by photocatalytic silk mask paper under UV lamps than under daylight lamps, and the more the load of nano-TiO₂ on the silk mask paper, the higher the degradation rate of formaldehyde within the same time.     

Properties of thermoplastic starch from cassava bagasse and cassava starch and their blends with poly (lactic acid)

Cassava bagasse is an inexpensive and broadly available waste byproduct from cassava starch production. It contains roughly 50% cassava starch along with mostly fiber and could be a valuable feedstock for various bioproducts. Cassava bagasse and cassava starch were used in this study to make fiber-reinforced thermoplastic starch (TPS_B and TPS_I, respectively). In addition, blends of poly (lactic acid) and TPS_I (20%) and TPS_B (5, 10, 15, 20%) were prepared as a means of producing low cost composite materials with good performance. The TPS and PLA blends were prepared by extrusion and their morphological, mechanical, spectral, and thermal properties were evaluated. The results showed the feasibility of obtaining thermoplastic starches from cassava bagasse. The presence of fiber in the bagasse acted as reinforcement in the TPS matrix and increased the maximum tensile strength (0.60 MPa) and the tensile modulus (41.6 MPa) compared to cassava starch TPS (0.40 and 2.04 MPa, respectively). As expected, blending TPS with PLA reduced the tensile strength (55.4 MPa) and modulus (2.4 GPa) of neat PLA. At higher TPS_B content (20%) the maximum strength (19.9 MPa) and tensile modulus (1.7 GPa) were reduced about 64% and 32%, respectively, compared to the PLA matrix. In comparison, the tensile strength (16.7) and modulus (1.2 GPa) of PLA blends made with TPS_I were reduced 70% and 51% respectively. The fiber from the cassava bagasse was considered a filler since no increase in tensile strength of PLA/TPS blends was observed. The TPS_I (33.1%) had higher elongation to break compared to both TPS_B (4.9%) and PLA (2.6%). The elongation to break increased from 2.6% to 14.5% by blending TPS_I with PLA. In contrast, elongation to break decreased slightly by blending TPS_B with PLA. Thermal analysis indicated there was some low level of interaction between PLA and TPS. In PLA/TPS_B blends, the TPS_B increased the crystallinity of the PLA component compared to neat PLA. The fiber component of TPS_B appeared to have a nucleating effect favoring PLA crystallization.     

Canopy reflectance in two castor bean varieties (Ricinus communis L.) for growth assessment and yield prediction on coastal saline land of Yancheng District, China

A field experiment was conducted in 2007-2009 in coastal saline regions of Yancheng city in Jiangsu province of China (120°13′E, 33°38′N). The experiment was to investigate relationships among canopy spectral reflectance, canopy chlorophyll density (CCD), leaf area index (LAI), and yield of two Chinese castor varieties (Zi Bi var. and Yun Bi var.) across four N fertilizer rates of 0, 90, 180, and 360 kg N ha⁻¹. These N rates were used to generate a wide range of difference in canopy structure and seed yield. Measurements of canopy reflectance were made throughout the growing season using a hand-held spectroradiometer. Samples for CCD and LAI were obtained on days that reflectance measurements were made. Fifteen hyperspectral reflectance indices were calculated. Canopy spectral characteristics were heavily influenced by saline soil background in the rapid growing period (RGP), thus hyperspectral data obtained in this period were not suited for reflecting castor growth condition or predicting final yield. CCD increased linearly with most reflectance indices in the full coverage period (FCP) and senescent period (SP) for the two castor varieties, whereas LAI did not. Most of reflectance indices were significantly correlated with yield of two varieties in different growing periods. The OSAVI model provided the best yield prediction for Zi Bi var. with predicted values very close to observed ones (R² = 0.799), and the mSRVI705 model was well used for Yun Bi var. yield estimation (R² = 0.759). These results indicate that the hyperspectral data measured at appropriate time could be well used for castor yield estimation.     

Insecticidal and repellent activity of selected essential oils against of the pollen beetle, Meligethes aeneus (Fabricius) adults

The essential oils from 9 aromatic plants were tested on repellency and mortality of Meligethes aeneus adults. All the tested essential oils caused high mortality of M. aeneus adults in the tarsal tests. The lethal doses after 6 h exposure were ranged between 197 and 1508 μg cm⁻². Essential oils obtained from Carum carvi and Thymus vulgaris were most efficient where LD₅₀ was estimated as 197 and 250 μg cm⁻², respectively.Repellency declined in all the essential oils as a function of time. The longest persistence time was determined for essences obtained from C. carvi and T. vulgaris where significantly the highest repellent index of 65.6% and 63.8%, respectively, was determined. Repellent index lower than 15% was determined for the remaining essential oils.     

Chitosan enhances withanolides production in adventitious root cultures of Withania somnifera (L.) Dunal

Calli were obtained from leaf, cotyledon and internode explants of in vitro-grown plants of Indian cultivar of Withania somnifera in MS medium supplemented with 2, 4-D (2.0 mg l⁻¹) and Kinetin (0.2 mg l⁻¹). The brown, semi-friable callus (500 mg FW) derived from leaf explants produced higher number of primary adventitious roots (9 roots/callus) in half strength MS medium fortified with IBA (0.5 mg l⁻¹) and NAA (0.1 mg l⁻¹). The primary adventitious roots with an inoculum mass of 15 g FW were cultured for 6 weeks in the same medium for secondary adventitious root proliferation. Elicitation of abiotic elicitor, aluminium chloride at 10 mg l⁻¹ at the end of 4 weeks culture with 4 h exposure time enhanced withanolides productivity. Under similar culture conditions, the biotic elicitor, chitosan at 100 mg l⁻¹ stimulated higher production of all withanolides when compared to aluminium chloride treatment. This is the first report on the use of callus-derived adventitious root culture for the enhanced production of withanolides upon chitosan elicitation.     

Nitrogen in sugarcane derived from fertilizer under Brazilian field conditions

Nitrogen (N) fertilization of sugarcane crops is a common practice used to reach sustainable levels of productivity, both for plant cane and especially for the ratoon. However, when evaluating the amount of N in the plant derived from fertilizer (NDDF) at harvest, this contribution is approximately 20% of total plant biomass N, which raises questions regarding the efficiency of N fertilization. The goal of this study was to evaluate the N derived from fertilizer (NDFF) during the sugarcane crop development, for both plant cane and first ratoon crop cycles. Two field experiments were performed in São Paulo State, Brazil, in Arenic Kandiustults and in Typic Eutrustox. The sugarcane was mechanically harvested without burning. N fertilizer for both the plant cane (doses of 40, 80 and 120 kg ha⁻¹ of N as urea) and the first ratoon (doses of 50 and 100 kg ha⁻¹ of N as ammonium sulfate) was labeled ¹⁵N. The results showed that NDFF contributed up to 40% of the total N in the plant cane at initial stages of development. The magnitude of this contribution decreased during stages of maturity to approximately 10% of total N at harvest. In the first ratoon, application of N fertilizer was more effective for crop nutrition, constituting up to 70% of total N in initial stages of development and decreasing through the cycle, reaching approximately 30% at harvest. Therefore, studies that evaluate NDDF only at harvest can lead to underestimating the role of N fertilizer for sugarcane nutrition. The higher NDFF in ratoon explains why this crop cycle presents a more consistent response to N fertilization than plant cane, as observed in several studies developed under Brazilian conditions in the last decades.