High Hemicellulose Content Research Articles

Multi-step kinetic mechanism coupled with CFD modeling of slow pyrolysis of biomass at different heating rates

This study employed numerical modeling to investigate the reactivity and kinetics involved in the slow pyrolysis of lignocellulosic biomass. The model integrates a biomass multi-step kinetics scheme with heat, momentum, and mass transfer, and it was based on the transport of species and flow in a porous medium approach. To develop the multi-step kinetics model, two samples of biomass, avocado stone (AS) with a high hemicellulose content and α-cellulose (CEL), were subjected to TGA experiments in an inert atmosphere. Furthermore, several experimental data in the literature on the evolution of slow pyrolysis products and data obtained by TGA experiments were considered to refine and validate the proposed kinetic mechanism. The temperature range, from 25 to 700 °C, was explored using different heating rates (10, 20, and 40 °C/min). Experimental results showed that CO and CO2 are the predominant gases during primary devolatilization, whereas H2 and CH4 result from secondary reactions at temperatures above 400 °C. The proposed mechanism involves computational fluid dynamic (CFD) simulations of laboratory-scale biomass pyrolysis, comparing temperature and species concentrations with experimental data. The predicted results for individual non-condensable gas mass yields showed an average relative error of below 6.90 % and 11.59 % for CEL and AS, respectively. In the case of biochar, the error was 6.41 % and 9.74 % for AS and CEL, respectively. The developed kinetic model can be applied to simulate the slow pyrolytic degradation of biomass based on its chemical composition.

Preparation of natural antibacterial regenerated cellulose fiber from seed-type hemp

Seed-type hemp fiber is hard to spinning and weaving because of its high lignin and hemicellulose content. In this work, the impurities in seed-type hemp fiber were removed by alkali degumming method, ammonium oxalate-complex enzyme method, ethylenediamainetetraacetic acid disodium -complex enzyme method, ammonium oxalate-complex enzyme-chemical method and ethylenediamainetetraacetic acid disodium -complex enzyme-chemical method, and the results were compared. The fibers were characterized by scanning electron microscopy (SEM) and fourier-transform infrared spectroscopy (FTIR). The fiber after impurity removal is prepared into pulp, and the structure of pulp was characterized by fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The hemp pulp was dissolved into ZnCl2 aqueous solution at a specific temperature to prepare a spinning solution and spun to produce antimicrobial seed-type hemp regenerated cellulose fibers by using a self-made spinning machine. The surface morphology, strength, moisture regain, and antibacterial properties were evaluated, the regenerated fibers had a superior performance.

Effect of pulp cell wall polysaccharides on citrus fruit with different mastication traits.

Mastication trait is a primary quality attribute of citrus fruit, influencing consumer demands and industrial processing conditions. However, the underlying causes of differences in mastication traits of citrus remain unclear. In this study, microscopy, spectroscopy and diffraction techniques were applied to investigate the physicochemical properties of Hongmeiren (HMR), Satsuma (WM) and Nanfeng tangerine (NF) with superior, moderate and inferior mastication traits, respectively. Ultrastructure indicated that NF had more neatly arranged and regularly shaped cells than HMR and WM. The monosaccharide composition of NF revealed that multi-branched Na2CO3-soluble pectin (NSF) enhanced intercellular adhesion. Additionally, FT-IR analysis revealed more intense vibrations of O2-H····O6 intramolecular hydrogen bonds within NF cellulose, which resulted in a higher crystallinity of cellulose (73.75%) than HMR (32.53%) and WM (43.76%). Overall, the high content and crystallinity of cellulose, the multi-branched NSF and the high content of hemicellulose contributed to the inferior mastication trait of citrus fruit.

Hemicellulose-rich paper-grade pulp as raw material for regenerated fibres in an ionic liquid-based process

Hemicellulose-rich pulp raw materials are avoided in the production of man-made cellulosic textile fibres due to hemicellulose reactivity with the currently used industrial solvent systems. Incorporation of hemicelluloses in regenerated fibres could, however, increase the share of used wood biomass and thus improve the environmental footprint of regenerated fibre products. Superbase ionic liquids have shown potential in dissolving and regenerating all the major wood polymers i.e. cellulose, hemicellulose and lignin into regenerated products. In this work, regenerated fibres were spun from hemicellulose-rich softwood and eucalyptus paper-grade pulps and eucalyptus dissolving pulp using a superbase ionic liquid [mTBNH][OAc]. Before dissolution and spinning, intrinsic viscosities of the paper-grade pulps were adjusted either enzymatically or by using a mild acid-treatment to improve dope rheology for dry-jet wet spinning. In fibre spinning, hemicellulose was found to regenerate in high yield and the obtained regenerated fibres had high dry tenacities (5.3 to 15 cN/dtex). The best mechanical properties were measured from fibres with high hemicellulose content (17.3% (w/w)). Pulp pretreatment was found to be critical for achieving good mechanical properties. Acid-pretreatment, which modified both cellulose and hemicellulose, yielded regenerated fibres with better mechanical properties compared to an enzyme-pretreatment which did not alter the hemicellulose structure. Removal of hemicellulose substituents and hydrolysis of hemicellulose backbone in acid-pretreatment may be the key to improved mechanical properties in hemicellulose-containing regenerated fibres. Enzymatic peeling and imaging with a xylan-specific monoclonal antibody (CCRC-M138) suggest that hemicelluloses were enriched to the outermost layers of the regenerated fibres.

Multi-environment evaluation of rice genotypes: impact of weather and culm biochemical parameters against sheath blight infection.

Sheath blight caused by Rhizoctonia solani is one of the major diseases of rice, causing widespread crop losses. The use of semi-dwarf rice varieties in the ongoing nutrient-intensive rice cultivation system has further accentuated the incidence of the disease. An ideal solution to this problem would be identifying a stable sheath blight-tolerant genotype. A multi-environment evaluation of 32 rice genotypes against sheath blight infection was conducted over six seasons across two locations (Agricultural Research Farm, Institute of Agricultural Sciences, Banaras Hindu University (28.18° N, 38.03° E, and 75.5 masl), for four years during the wet seasons (kharif) from 2015 to 2018 and two seasons at the National Rice Research Institute (20°27'09" N, 85°55'57" E, 26 masl), Cuttack, Odisha, during the dry season (rabi) of 2019 and the kharif of 2019, including susceptible and resistant check. Percent disease index data were collected over 4 weeks (on the 7th, 14th, 21st, and 28th day after infection), along with data on other morphological and physiological traits. The resistant genotypes across seasons were the ones with a higher hemicellulose content (13.93-14.64) and lower nitrogen content (1.10- 1.31) compared with the susceptible check Tapaswini (G32) (hemicellulose 12.96, nitrogen 1.38), which might explain the resistant reaction. Three different stability models-additive main effect and multiplicative interaction (AMMI), genotype + genotype x environment (GGE) biplot, and multi-trait stability index (MTSI)-were then used to identify the stable resistant genotypes across six seasons. The results obtained with all three models had common genotypes highlighted as stable and having a low area under the disease progress curve (AUDPC) values. The ideal stable genotypes with low disease incidence were IC 283139 (G19), Tetep (G28), IC 260917 (G4), and IC 277274 (G10), with AUDPC values of 658.91, 607.46, 479.69, and 547.94, respectively. Weather parameters such as temperature, rainfall, sunshine hours, and relative humidity were also noted daily. Relative humidity was positively correlated with the percent disease index.

Transforming non-wood feedstocks into dissolving pulp via organosolv pulping: An alternative strategy to boost the share of natural fibers in the textile industry.

This work evaluates wheat straw, switchgrass, and hemp hurd as potential alternatives for producing dissolving pulp using sulfur dioxide (SO2)-ethanol-water (SEW) pulping. The SEW process is described in detail for wheat straw, and the best pulping conditions for this feedstock were 130 °C, 4 h, and 10% SO2 concentration, comprised in a sulfur-ethanol-water ratio of 10-45-45. This resulted in a viscose-grade pulp with 93% α-cellulose, 2.0% hemicelluloses, <0.1% lignin, 0.2% ash content, and a viscosity of 4.7 cP. The best pulping conditions for wheat straw were applied to switchgrass and hemp hurd. Wheat straw and switchgrass had similar pulp quality, while hemp hurd pulp had a higher hemicellulose content and lower viscosity. This work suggests that non-wood feedstocks such as wheat straw and switchgrass can be promising alternatives for dissolving pulp production, which can help reduce the pressure on the textile industry to increase the use of natural fibers and mitigate the environmental impact of non-biodegradable synthetic fibers.

Biogas production potential of aquatic weeds as the next-generation feedstock for bioenergy production: a review.

Aquatic weeds have exceptionally high reproduction rates, are rich in cellulose and hemicellulose, and contain a negligible amount of lignin, making them an ideal crop for the next generation of biofuels. Previously reported studies proposed that water hyacinth, water lettuce, common duckweeds, and water spinach can be managed or utilized using different advanced techniques; from them, anaerobic digestion is one of the feasible and cost-effective techniques to manage these biowastes. The present study was carried out to investigate the potential of utilizing four common aquatic weed species (water hyacinth, water lettuce, common duckweeds, and water spinach) as substrates for anaerobic digestion in order to produce biogas for use in biofuels. The high reproduction rates and high cellulose and hemicellulose content, coupled with low lignin content, of these aquatic weeds make them ideal candidates for this purpose. The study evaluated the feasibility of using anaerobic digestion as a management technique for these aquatic weeds, which are often considered invasive and difficult to control. The results from various studies indicate that these aquatic weeds are productive feedstock options for anaerobic digestion, yielding a high biogas output. Among the aquatic weeds studied, water hyacinth, water lettuce, and common duckweeds exhibit higher methane production compared to water spinach. The study provides an overview of the characteristics and management strategies of these aquatic weeds in relation to biogas production, with possible future developments in the field.

Application of Biorefinery Concept to the Production of Bromelain, Ethanol, and Xylitol from Pineapple Plant Waste

The massive potential of pineapple fruit production can produce a sizable amount of waste, around 75% (w/w) of pineapple weight, contributing to global environmental problems. For this reason, biorefinery techniques are urgently needed to convert pineapple plantation waste into high-value-added bioproducts including bromelain, various sugars, xylooligoscharide, xylitol, and ethanol. The purpose of this study was to examine the effectiveness of converting pineapple plantation waste into bromelain, xylitol, and ethanol. In this study, the activity of the bromelain enzyme was tested in each part of the pineapple plant waste. The configuration of the hydrolysis and fermentation processes used to make ethanol and xylitol from the rest of the pineapple plant waste from bromelain extraction was also investigated. Bromelain is a proteolytic enzyme found in pineapple plants and can be isolated from every part of pineapple plant waste. Enzyme activity under several conditions, such as crude extract, pure extract, and dried extract, has been studied to determine the best conditions for the downstream process of this enzyme’s production in the future. The purification of bromelain involved the utilization of the precipitation method followed by dialysis, whereas the drying process of bromelain employed the freeze-drying method. The bromelain enzyme specific activity is shown to be highest in the pineapple stem, as observed in crude-extract (1.45 ± 0.06 CDU/mg), purified-extract (10.38 ± 0.06 CDU/mg), and dried-extract (12.05 ± 0.43 CDU/mg) conditions. Using the pineapple stem to extract bromelain can produce lignocellulosic waste, which is made up of 39.47% starch, 19.96% hemicellulose, 36.44% cellulose, and 6.05% lignin. The high content of starch, cellulose, and hemicellulose has the potential to be used as feedstock for ethanol and xylitol fermentation. In this study, ethanol and xylitol fermentation were carried out using two methods: separate hydrolysis and fermentation methods (SHF) and semi-simultaneous saccharification and fermentation methods (semi-SSF). As a result, fermentation using the semi-SSF method produced ethanol with a higher titer and yield (22.12 ± 0.05 g/L and 0.44 ± 0.00 g/g, respectively). However, the production of xylitol was found to be insignificant, regardless of whether it was obtained using SHF or semi-SSF. The purification of bromelain involved the utilization of the precipitation method followed by dialysis, whereas the drying process of bromelain employed the freeze-drying method.

Optimization of biohydrogen production by dark fermentation of African food-processing waste streams

In the challenge of mitigating greenhouse gases produced mainly by fossil fuels, the recovery of agricultural and food waste to produce biohydrogen by dark fermentation is considered a promising source for the future. However, industrial-scale production remains challenging and several parameters significantly influencing the application of the technology need to be finely tuned. In the present study, an evaluation of the production of biohydrogen from cassava and pineapple waste, widely available in many African countries, was carried out using different microbial consortia originating from industrial biogas plants in Italy. The production of biohydrogen was defined both by screening the most appropriate inoculum and by using a “centered composite design” to optimize the inoculum pretreatment time and the pH.From cassava waste, which is abundant of starch (43%), the highest hydrogen levels (62.32 mL H2/gVS) were obtained at pH 7.72 adopting a 4-h heat treated inoculum originating from an anaerobic digester fed with corn and barley silage. Higher hydrogen yields (75.50 mL H2/gVS) were achieved at pH 6 once pineapple, which has a high content of hemicellulose, was converted by another selected inoculum, isolated from an olive pomace treating plant, where hemicellulose is one of the most common polysaccharide. The correlation coefficients R2 and adjusted R2 are close to unity, proving the model to be appropriate to express the concentration of hydrogen produced.This combined approach performed successfully and represents a strong strategy to optimize the production of biohydrogen from agricultural residues even in African contexts.

Production and Characterization of Cellulosic Pulp from Mango Agro-Industrial Waste and Potential Applications.

The growing demand for cellulosic pulp presents an opportunity to explore alternatives to this material, focusing on utilizing agro-industrial residues. Mango's tegument is a rich source of cellulose, making it a valuable raw material for manufacturing single-use articles or blends with biopolymers. In this sense, employing conventional alkaline and acid chemical treatments, the mango's tegument was treated to obtain cellulosic pulp. The teguments were subjected to treatment with alkaline solutions (2% and 4% NaOH w/v) at 80 °C for 1 or 2 h or with an acetic acid solution (1:1 or 1:2 CH3COOH:H2O2) at 60-70 °C for 1 or 2 h. After treatment, an evaluation was conducted to assess the yield, color, chemical analysis, and structural, thermal, and morphological properties. The alkali treatments produced cellulosic pulps with a light color with 37-42% yield and reduced hemicellulose content. The acid treatments produced orange-brown cellulosic pulp with 47-48% yield and higher hemicellulose content. The acid pulps were thermally more stable (maximum decomposition at 348-357 °C) than the alkali pulps (maximum decomposition at 316-321 °C). The crystallinity index demonstrated that both treatments increased the crystallinity of the cellulose pulps compared with the untreated tegument. The thermal stability of cellulosic pulp at the processing temperatures of disposable tableware (50-120 °C) revealed that plates, bowls, trays, and cups could be produced. Another potential application is as a component of blends with biopolymers to make straws or rigid food packaging (trays) with reinforced structures.

Experimental investigation on effect of season on the production of bioethanol from wheat-stalk (WS) using simultaneous saccharification and fermentation (SSF) method

Global dependency on conventional fuel, its limited stock, and their adverse effects on the environment have driven researchers into alternative fuel. Wheat-stalk (WS), which is a residue of the harvested wheat crop, is considered a potential feedstock for bioethanol production as an alternative fuel due to its high cellulose and hemicellulose content and abundant availability. The objective of this work is to optimize the environment condition for fermentation in the different seasons to get the maximum bioethanol production yield from wheat-stalk straw (WSS) by using minimal laboratory resources. In this study, field collected WS was taken for physical treatment to get size less than 1 mm. Steam explosion pretreatment of WSS was performed to increase its accessible surface area and to reduce degree of polymerization. Next, to remove lignin, it was pretreated with alkali (1 M NaOH) with a solid-loading of 1:15 (w/v) at pH 10. After that, an acidic pretreatment was performed with 0.1 N diluted H2SO4 at pH 4.8 to increase anaerobic digestibility and for quicker hydrolysis. The pretreated WSS slurry was further enzymatically hydrolysed for 48 h to have monomeric sugar from cellulose and hemicellulose by adding cocktail of three enzymes amylase, cellulase, and hemicellulase with amount of 0.1% w/v of each. After that simultaneous saccharification and fermentation (SSF) were performed to convert monomeric sugar into bioethanol in the presence of microbial yeast media containing yeast (1% w/v), and peptone (2% w/v) under anaerobic conditions at pH 5.0. It has been found that the minimum time required during SSF for bioethanol production is different for different seasons. In addition, the fermentation period is shorter in monsoon as compared to spring and summer. As the fermentation period increases, the production of bioethanol yield increases up to a certain limit. The maximum bioethanol yields from the WSS were obtained as 0.183, 0.19, and 0.21 ml/g of dry WSS biomass in the spring, summer, and monsoon seasons for the fermentation period of 15, 9, and 11 days respectively. Consequently, it has been found that the enhancement in maximum bioethanol yield in the monsoon season is 8.42% and 12.57% as compared to the summer and spring seasons, respectively.

Effect and mechanism analysis of dual enzyme pretreatment on enhancement of volatile fatty acids production in kitchen waste anaerobic acidification

The high content of cellulose and hemicellulose in kitchen waste (KW) results in a slow hydrolysis rate and subsequently hinders the yields of volatile fatty acids (VFAs) in anaerobic acidification. In this study, cellulase and hemicellulase were used for the pretreatments of KW to tackle the problem of difficult hydrolysis in anaerobic acidification. The results indicated that the joint use of double enzymes significantly improved the hydrolysis of cellulose and hemicellulose during pretreatment, thus enhancing the VFAs production in anaerobic acidification. The highest production of TVFAs was 50.73 ± 2.10 g COD/L and it was improved by 62.77% compared with the unpretreated group. In addition, the 16S rRNA amplicon sequencing analysis showed that the relative abundance of Firmicutes related with the VFAs production increased from 17.77% to 50.55%. The potential metabolism function analysis (PICRUSt2) indicated that the enrichment of glyceraldehyde-3-phosphate dehydrogenase (EC:1.2.1.9) and acetyl-CoA C-acetyltransferase (EC:2.3.1.9) contributed to the production of VFAs in AD. The results suggested that collaborative enzyme pretreatment could be one of the effective methods for the hydrolysis of cellulose and hemicellulose in KW and provided constructive mechanistic insights into recovering valuable products from KW.

Influence of the cellulose purification process on the properties of aerogels obtained from rice straw

Cellulose aerogels were obtained from purified rice straw cellulose fibres (CF) by applying different extraction methods: the conventional alkaline treatment (ALK) and alternative aqueous extraction based on the ultrasound combined with reflux heating (USHT) and subcritical water extraction (SWE) (160 and 180 °C). The composition and properties of the CFs were significantly affected by the purification process. The USHT treatment was as efficient as the ALK at eliminating the silica content, but the fibres maintained a notable ratio of hemicellulose (∼16 %). The SWE treatments were not so effective at removing silica (15 %) but greatly promoted the selective extraction of hemicellulose, especially at 180 °C (3 %). The CF compositional differences affected their hydrogel formation capacity and the properties of aerogels. A higher hemicellulose content in the CF led to better-structured hydrogels with better water-holding capacity, while the aerogels exhibited a more cohesive structure with thicker walls, higher porosity (99 %) and water vapour sorption capacity, but lower liquid water retention capacity (0.2 g/g). The residual silica content also interfered with the hydrogel and aerogel formation, giving rise to less structured hydrogels and more fibrous aerogels, with lower porosity (97–98 %).

Effect of enzymatic treatment on Eucalyptus globulus vessels passivation

Hardwood vessel elements generate problems in industrial uncoated wood-free printing paper operation, causing vessel picking and ink refusal. These problems are mitigated using mechanical refining at the cost of paper quality. Vessel enzymatic passivation, altering its adhesion to the fiber network and reducing its hydrophobicity is a way of improving paper quality. The object of this paper is to study how the enzymatic treatment by xylanase and by an enzymatic cocktail containing cellulases and laccases affect elemental chlorine free bleached Eucalyptus globulus vessel and fiber porosities, bulk, and surface chemical compositions. Thermoporosimetry revealed the vessel structure to be more porous, surface analysis showed its lower O/C ratio and bulk chemistry analysis its higher hemicellulose content. Enzymes had different effects on porosity, bulk and surface composition of fibers and vessels, affecting vessel adhesion and hydrophobicity. Vessel picking count decreased 76% for papers containing vessels treated with xylanase and 94% for the papers with vessels treated with the enzymatic cocktail. Fiber sheet samples had lower water contact angle (54.1º) than vessels rich sheets (63.7º), that reduced with xylanase (62.1º) and cocktail (58.4º). It is proposed that differences in vessel and fiber porosity structures affect the enzymatic attacks, eventually causing vessel passivation.

Valorisation of Underutilized Grass Fibre (Stem) as a Potential Material for Paper Production.

An integrated and feasible approach was proposed using the underutilized grass fibre (stem) derived from Napier grass and sugarcane for paper production in this study. To enhance paper strength, pre-hydrolysis and beating techniques have been used to improve the chemical pulps and mechanical pulping process, respectively. Napier grass and sugarcane are promising non-wood sources for pulp production, owing to their high cellulose and low lignin and extractive content. With the additional mild alkaline pre-treatment to the mechanical pulping process, the lignin content was greatly reduced. The results reveal that the mechanical pulping with alkaline pre-treatment may indeed potentially replace the most prevalent pulping process (chemical pulping). As evidenced by the paper strength properties, mechanical pulping is far more suitable for grass-type biomass, particularly Napier grass, which had a folding endurance capability five times greater than chemical pulping. Furthermore, the remaining high hemicellulose content from mechanical pulping contributed to a high pulp yield, while also facilitating the fibrillation on the sugarcane's laboratory paper handsheet. The findings also demonstrated that the additional beating process from chemical pulping causes the fibres to be drawn toward each other, resulting in a more robust fibre network that contributes to good paper strength. Consequently, this work sheds new light on the development of advanced paper derived from grass fibre.

Effect of hemicellulose extraction pretreatment on sulfonated corncob biochar for catalytic biodiesel production

In this work, waste corncob with high hemicellulose content was selected as the carbon source to investigate the effect of hemicellulose extraction on the prepared sulfonated biochar for biodiesel production. After hemicellulose extraction, the optimized sulfonated biochar with a maximum -SO3H density of 2.05 mmol/g was synthesized under 3 h of carbonization at 300 °C, then 2 h of sulfonation at 90 °C. For the esterification, the 98.5% oleic acid equilibrium conversion was achieved under optimized reaction parameters: a 12:1 molar ratio (methanol/oleic acid) and a 10 wt% catalyst dosage at 65 °C for 4 h. The catalyst still reached 70% conversion efficiency after 10 cycles, which proved that the hemicellulose extraction not only played a role in the rational utilization of biomass but also the significantly-improved catalyst lifetime was beneficial to the sustainable production of biodiesel.

Dissecting the Genetic Mechanisms of Hemicellulose Content in Rapeseed Stalk

Polysaccharides such as hemicellulose in rapeseed can be used as an abundant resource to develop biomass energy. In the present study, the hemicellulose content in the middle stalk and taproot of a rapeseed core population of 139 accessions in Guizhou, Hubei and Anhui provinces was determined. Genotyping of the core population was carried out by a 60 K single nucleotide polymorphism chip, and a genome-wide association study (GWAS) was performed to reveal the associated sites of hemicellulose content in rapeseed. The results of the GWAS showed that 28 SNPs (p ≤ 0.001) were significantly associated with hemicellulose content, and revealed that three sites—qHCs.C02 (contribution rate = 17.20%), qHCs.C05 (10.62%), and qHCs.C08 (8.80%)—are significantly associated with hemicellulose content in the stalk and three sites—qHCt.A09 (9.49%), qHCt.C05 (9.18%) and qHCt.C08 (13.10%)—are significantly associated with hemicellulose content in the taproot. Seven candidate genes associated with hemicellulose synthesis were identified in these major loci. Further RNA-seq analysis showed that two key differentially expressed genes (BnaC05G0092200ZS and BnaC05G0112400ZS) involved in hemicellulose synthesis were identified as having underlying QTL. This study excavated the key loci and candidate genes for regulating hemicellulose synthesis, providing a theoretical basis for developing rapeseed varieties with high hemicellulose content. At the same time, our results will be helpful in producing rapeseed cultivars with high lodging-resistance as well as highlighting the value of rapeseed as a resources for the bioenergy industry.

Effect of bamboo pith ring on the stability of the gluing interface

As a natural bamboo structure, bamboo pith ring (BPR) is commonly discarded from bamboo composites because it influences the gluing process and might cause complex handling. This study founds that the cells in BPR and bamboo middle (BM) are vertically staggered, forming vertical interlacing layers at the bonding interface in Arc-shaped Bamboo Natural Laminated Lumber (ABNLL). The role of BPR in the bonding interface was analyzed from macroscopic to cell wall scale. The retention of BPR can reduce the longitudinal, radial, and tangential deformation of bamboo blocks and composites during shrinkage and swelling. This phenomenon may be since the deformation direction of the cells in BPR and BM is vertical in the process of water absorption and dehydration, and the existence of BPR inhibits the deformation of BM. The deformation of cells in different directions in BPR and BM results from microfibrils' arrangement and chemical properties. The arrangement direction of microfibrils in BPR and BM is perpendicular to each other, leading to the vertical deformation of cell deformation in water absorption and water loss. BPR has low crystallinity (24.01%), a large microfibril angle (16.22°), high hemicellulose content, and is more sensitive to water, so BPR has a faster deformation rate and larger deformation range than BM. BPR has little effect on the mechanical properties of bamboo composites. In addition, retaining BPR increased the mass and thickness of bamboo by 7.43% and 9.40%, respectively.

Characterization of Paper Mulberry Bast Fiber and Cotton Linter Fiber for Nanocellulose Production

This study investigates the suitability of non-woody fibers such as paper mulberry bast fiber (PMBF) and cotton linter mixed pulp (CLMP) as raw materials for the production of nanocellulose. PMBF, CLMP, and hardwood bleached kraft pulp (HwBKP) were used as a control, and their chemical compositions, fiber characteristics, initial freeness, crystallinity, and shape were measured. Based on these findings, an efficient method for producing various types of nanocelluloses using PMBF and CLMP was explored.BRThe chemical compositions revealed that PMBF and CLMP had higher alpha cellulose content than HwBKP, which indicates the functionality of using two non-woody fibers in the production of nanocellulose. The longest PMBF had higher initial freeness and crystallinity than CLMP and HwBKP, which indicates that a high cost for chemical or mechanical pretreatment is required to produce cellulose nanofibril (CNF) using PMBF. Additionally, the CLMP had the lowest crystallinity of the three materials due to its relatively high content of hemicellulose and lignin, as revealed in the chemical composition analysis, and it had lower initial freeness than HwBKP, which indicates that the CLMP can be easily fibrillated through mechanical treatment compared to a PMBF.BRThus, using PMBF as a raw material for cellulose nanocrystal (CNC) produced by acid hydrolysis and CLMP as a raw material for CNF produced by mechanical treatments was efficient.

Aquatic macrophytes (Spirogyra porticalis and Nymphaea L.) as substrates for biofuel production: potentials and challenges

Green fuel represents one of the most promising means of sustainably replacing liquid fuels, and freshwater macrophytes has become one of the auspicious substrates for biofuel production due to high cellulose and hemicellulose contents. In this study, the use of Spirogyra porticalis and Nymphaea alba Linn for biodiesel, bioethanol and biogas production was investigated with other feedstocks (rice husk and biochar) using dry and wet extraction methods. Spirogyra porticalis and Nymphaea alba Linn were harvested from a freshwater lake in Ndufu Echara in Ikwo Local Government, Ebonyi State, Nigeria and thoroughly washed. Biodiesel, bioethanol and biogas production by an alkali-catalysed transesterification using mechanical and chemical methods, acid and base simultaneous saccharification and fermentation, and anaerobic digestion was carried out, respectively. Results showed that freshwater macrophytes produced more biodiesel compared to rice husk and biochar. S. porticalis and Nymphaea L. yielded higher biodiesel using chemical and mechanical methods, respectively. Quality evaluation of the diesel oil according to ASTM standard revealed that chemical method was the most proficient for biodiesel production because of its proximity to ASTM D6751 standard. For bioethanol, acid hydrolysis (1M HCl) produced more bioethanol than the base (1M NaOH) with Nymphaea L. yielding 60% ethanol. However, the macrophytes did not generate biogas after 30-d of anaerobic digestion compared to other feedstocks. Further analysis revealed sample acidification and inhibitions on the anaerobes responsible for anaerobic digestion (p<0.05). This suggests that acidification and/or toxicity may be a major factor associated with anaerobic digestion and biogas production from aquatic macrophytes. Thus, optimization and/or combined pre-treatment methods (biological, mechanical, enzymatic) are recommended. This suggests that Spirogyra porticalis and Nymphaea alba Linn could be major substrates for biofuel production, and tropical freshwater ecosystems can be good for their large-scale cultivation