Cellulose Yield Research Articles

Effect of co-culture of Komagataeibacter nataicola and selected Lactobacillus fermentum on the production and characterization of bacterial cellulose

Using pre-fermented coconut water brings about a high yield of bacterial cellulose (BC) from Komagataeibacter strains in food industry, but the production is unstable and even risky. Therefore, finding a controllable and high-yield production mode of BC is necessary. Our previous study has showed that Lactobacillus is one of the dominant genera in pre-fermented coconut water. Based on this, the effect of co-culture of K. nataicola and 17 coconut-sourced Lactobacillus spp. strains on the production of BC was investigated in this study. Results suggested that co-culture of K. nataicola and Lactobacillus spp. strains had varied effects on the production of BC. Co-culture of K. nataicola Q2 and L. fermentum SR can effectively improve the production of BC via affecting the formation of β-1,4-glucan chains and crystallization of microfibrils. Moreover, direct and indirect pathways were involved in promoting the formation of β-1,4-glucan chains in the co-culture system. The co-culture of K. nataicola Q2 and L. fermentum SR led to the production of BC membrane with higher crystallinity but lower thermal degradation, hardness, adhesiveness, and water holding capacity. This research provides a reference for realizing controllable increase of BC production and modification of BC.

Catalytic hydrolysis of corncob for production of furfural and cellulose-rich solids: Product characterization and analysis

Experiments were carried out to investigate cellulose and furfural from catalytic hydrolysis of corncob. This process improved the comprehensive utilization of hemicellulose and cellulose in biomass resources. Influence of factors (temperature, reaction time, concentration of catalysts, liquid to solid ratio (LSR)) on hydrothermal characteristics, furfural yield, properties and retention of cellulose were investigated through orthogonal and parameter tests. Acetic acid (6 wt%) and FeCl3 (40 mM) achieved the highest furfural yield (47.60%) and relatively high cellulose retention ratio (71.84%) at 180 °C, 45 min, and 3 mL/g of LSR. While AlCl3 and citric acid obtained low furfural yield and the lowest cellulose retention ratio (8.38%). Furfural was dominant in distillated organics (GC-MS areas ≥97.9%), by contrast furfural, 5-hydroxymethyfurfural and vanillin were main organics in residual liquors. The peak of furfural yield switched to shorter reaction time as temperature increased. Combination of AlCl3 with acetic acid and citric acid accelerated cellulose degradation. NaCl inhibited furfural yield and promoted lignin decomposition. Higher temperature and greater concentration of FeCl3 contributed to reduced crystallinity of cellulose during hydrothermal treatment.

Enhanced production of fibrous bacterial cellulose in Gluconacetobacter xylinus culture medium containing modified protein of okara waste

In Gluconacetobacter xylinus cultivation for bacterial nanocellulose production, agro-industrial wastes, soybean residual okara, okara extracted protein, and modified okara protein, were used as a protein source. In comparison with homogenized raw okara and protein extracted from raw okara, acetic-acid modified protein provided the higher cellulose yield (2.8g/l at 3 %w/v protein concentration) due to the improved protein solubility in the culture medium (89 %) and smaller particle size (0.2μm) leading to facile uptake by the bacteria. Importantly, pH of the culture medium containing the modified protein measured before and after the cultivation was similar, suggesting the buffering capacity of the protein. Nanocellulose fibers were then produced densely in the network of hydrogels with high crystallinity nearly 90 %. Based on the results, economic constraints around nanocellulose production could be alleviated by valorization of okara waste, which provided enhanced sustainability.

Achieving efficient pretreatment of corn straw at elevated temperatures via constraining cellulose degradation

Greatly reducing the cellulose crystallinity and lignin content of lignocellulose can substantially improve the enzymatic hydrolysis efficiency, dramatically reducing the enzyme dosage; however, it is difficult to be simultaneously achieved. A solution was put forward - biomass pretreatment was carried out with the binary system consisted of 1-n-butyl-3-methylimidazole chloride (BMIMCl) and arginine (Arg) at temperatures higher than the glass transition temperature of lignin (Tg-lignin). The cellulose crystallinity decreased because of hydrogen bonding with BMIMCl. Delignification was promoted via raising the temperature higher than the Tg-lignin, while cellulose degradation was constrained by Arg. The delignification rate reached 90.36 %. The yield of cellulose remained at a level of 88.89 %, while the Crystallinity Index (CI) of cellulose decreased from 36.13 % (raw corn straw) to 13.50 % (regenerated material, RM). It was found that the average molecular weight (Mw) of lignin decreased from 1632 g/mol to 584 g/mol after pretreatment, indicating the lignin was depolymerized; the 2D-HSQC result showed the β-O-4′ bond of lignin was broken. Because the cellulose crystallinity and the lignin content of the regenerated material were reduced greatly at the same time, the RM was easily hydrolyzed by cellulase. The enzymatic hydrolysis glucose yield of the RM was 3.75 times that of raw corn straw when the enzyme dosage was only 0.41 FPU/g sample, reaching 99.5 %. The IL was successfully recycled four times, and the recovery rate was higher than 93 % each time. RM obtained in four cycles maintained high lignin removal rate and enzymatic hydrolysis glucose yield. The degradation products of hemicellulose and lignin were the main impurities in the recovered IL. This work may provide a new solution for green and efficient biomass pretreatment.

Boosting VFAs production during the anaerobic acidification of lignocellulose waste pulp and paper mill excess sludge: Ultrasonic pretreatment and inoculating rumen microorganisms

Ultrasonic pretreatment combined rumen microorganisms (RM) anaerobic hydrolysis was used as a novel method to boost volatile fatty acids (VFAs) production from lignocellulose waste pulp and paper mill excess sludge (PPES). To investigate the effect of ultrasonic on PPES degradation, various ultrasonic power levels and treatment time were used to treat PPES. The findings showed that ultrasonic pretreatment breaks the structure of PPES distinctly and significantly contributes to promoting PPES degradation. Under ultrasonic power level of 540 W and treatment time of 50 min conditions, the production of soluble chemical oxygen demand (SCOD), ammonia nitrogen (NH4+-N), reducing sugar, and soluble protein was 36.9, 16.9, 29.2, and 26.8 times of control-1, respectively. In the following RM anaerobic acidification experiment, VFAs production of PPES after ultrasonic treatment increased by 92 % compared to that of PPES without ultrasonic treatment and were much higher than that of the control-2 group without inoculating RM. During the fermentation stage, the degradation yield of cellulose, hemicellulose and lignin were 40.35 %, 58.35 % and 16.49 %, respectively. These results demonstrated that ultrasonic-RM treatment could improve the efficiency of the anaerobic acidification process and VFAs production and RM had a strong effect on degradation of hemicellulose and cellulose. In addition, Illumina MiSeq sequencing showed that the number of microbial species decreased, and the dominant flora changed.

Impact of rotation length of Eucalyptus globulus Labill. on wood production, kraft pulping, and forest value

Most of the wood from Eucalyptus globulus Labill. plantations in Uruguay is harvested for pulp industry at an average age of 11 years. In this study we evaluated the volume and quality of the wood produced and the economic return for owners using different rotation length (from 6 to 13 years) and two different provenances (Jeeralang, Australia and Chivilingo, Chile) in experimental plots planted at two different sites (southwest and southeast of Uruguay). Silvicultural practices, industrial process, and economic aspects of the plantations were evaluated by measuring the following variables: survival, individual and per hectare growth, basic density, cellulose yield, wood consumption, cellulose production per hectare, dry solids content, fiber length, paper resistance, internal rate of return, and soil expectation value. The results showed that an increase in the harvest age generates: (i) an increase in the production of wood and cellulose per hectare at decreasing rates; (ii) an increase in wood density and yield; (iii) a reduction in the consumption of wood and solid contents in the cooking liquor; and (iv) a reduction in economic profitability at the farm level. No differences were found in the fiber length and resistance properties of the paper from wood harvested at different ages.

Eco-Friendly Bioprocessing Oil Palm Empty Fruit Bunch (Opefb) Fibers Into Nanocrystalline Cellulose (Ncc) Using White-Rot Fungi (Tremetes Versicolor) and Cellulase Enzyme (Trichoderma Reesei)

The oil palm empty fruit bunch (OPEFB) as solid biomass of palm oil mill industry is available in abundance and has the potential to be utilized as the raw material of nanocrystalline cellulose (NCC). This research aims to investigate the effect of bioprocess treatment (bio-delignification, bio-bleaching, and enzymatic hydrolysis) on the nanocrystalline cellulose synthesized from OPEFB. The bio-delignification of OPEFB fiber was carried out using white-rot fungi (Tremetes versicolor and pre-bleaching pulp with xylanase. Trichoderma reesei, a cellulase enzyme type was used to hydrolyze the OPEFB fiber into nano-sized cellulose. The result exhibits that the cellulose content of OPEFB pulp using bio-delignification increased significantly compared to chemical treatment. Furthermore, the concentration of enzyme and hydrolysis time in the synthesis treatment affect reducing average particle size and increasing the crystallinity index while decreasing the yield of NCC produced. The synthesis process was under optimal processing conditions at 1% enzyme concentration and 3 days of hydrolysis time resulting in the NCC product with 155 nm of average particle size, 66.78% of crystallinity index, and a yield of 38.28%. The bioprocess technology applied in this study could improve the cellulose yield of OPEFB and enhance the quality parameters of NCC products such as particle size and crystallinity index.

Enhancing Glucose Recovery from Hibiscus cannabinus L. through Phosphoric Acid Pretreatment

Non-food lignocellulosic biomass is an attractive source owing to its abundance as a renewable resource and cost-effectiveness. Hibiscus cannabinus L., commonly known as kenaf, is a fiber-producing plant with high cellulose yield and non-food biomass. This study aimed to enhance the glucose recovery (GR) of kenaf biomass (KB). The bark and core fibers of KB are rich in glucan content and low in lignin content. Based on its glucan and lignin contents, KB has considerable potential as a feedstock for synthesizing monomer sugars, which can produce biofuel and high-value compounds. Therefore, the bark and core fibers were treated at a moderate temperature with various concentrations of phosphoric acid, followed by enzymatic hydrolysis. After pretreatment, the chemical composition of both feedstocks was changed. Phosphoric acid substantially affected the elimination of partial lignin and hemicellulose, which led to enhanced enzymatic hydrolysis. The maximum hydrolysis efficiency (HE) and GR of bark and core fibers were achieved when both feedstocks were treated with 75% phosphoric acid. Compared with untreated feedstocks, HE increased by approximately 5.6 times for bark and 4.7 times for core fibers. However, GR was enhanced approximately 4.9-fold for bark and 4.3-fold for core fibers.

Comparative study of Mg-phosphate/cellulose and struvite/cellulose composites: Green synthesis, degradation, and biocompatibility

This present study was mainly aimed at comparing the effect of using two bioresorbable ceramics of the same synthesis origin (Mg-phosphate (MP) and struvite (ST) derived from it) with bacterial cellulose (BC), using bacterial strain Gluconacetobacter xylinum ATCC 10245, to prepare in situ new composites on eco-friendly green synthesis process of the BC, in vitro degradation and biocompatibility. The obtained composites were characterized by TGA, FTIR, and XRD. The in vitro and biodegradation tests were performed in the simulated body fluid (SBF), and the cytotoxicity test was carried out against the Vero cell line. The XRD results showed farringonite and struvite phases were the main crystalline phases. Moreover, the addition of either MP or ST increased the bacterial cellulose yield, and the maximum yield was 1.51–1.56 g/L at a ceramic concentration range 0.25–0.50%. Furthermore, the in vitro bioactivity test presented that bacterial cellulose/struvite composite was the more induced formation of Ca-phosphate layer after immersion in SBF than that of bacterial cellulose/Mg-phosphate composite, and the Ca/P ratio of the former one (Ca/P = 1.11) was closer to the hydroxyapatite ratio (Ca/P = 1.67) the last composite (Ca/P = 0.30). Moreover, bacterial cellulose/struvite showed better compatibility and viability with Vero cells than bacterial cellulose/Mg-phosphate composite. In conclusion, the new bioactive composites synthesized by green and eco-friendly methods are expected to be suitable for bone grafting and engineering applications.

Better under stress: Improving bacterial cellulose production by Komagataeibacter xylinus K2G30 (UMCC 2756) using adaptive laboratory evolution.

Among naturally produced polymers, bacterial cellulose is receiving enormous attention due to remarkable properties, making it suitable for a wide range of industrial applications. However, the low yield, the instability of microbial strains and the limited knowledge of the mechanisms regulating the metabolism of producer strains, limit the large-scale production of bacterial cellulose. In this study, Komagataeibacter xylinus K2G30 was adapted in mannitol based medium, a carbon source that is also available in agri-food wastes. K. xylinus K2G30 was continuously cultured by replacing glucose with mannitol (2% w/v) for 210 days. After a starting lag-phase, in which no changes were observed in the utilization of mannitol and in bacterial cellulose production (cycles 1–25), a constant improvement of the phenotypic performances was observed from cycle 26 to cycle 30, accompanied by an increase in mannitol consumption. At cycle 30, the end-point of the experiment, bacterial cellulose yield increased by 38% in comparision compared to cycle 1. Furthermore, considering the mannitol metabolic pathway, D-fructose is an intermediate in the bioconversion of mannitol to glucose. Based on this consideration, K. xylinus K2G30 was tested in fructose-based medium, obtaining the same trend of bacterial cellulose production observed in mannitol medium. The adaptive laboratory evolution approach used in this study was suitable for the phenotypic improvement of K. xylinus K2G30 in bacterial cellulose production. Metabolic versatility of the strain was confirmed by the increase in bacterial cellulose production from D-fructose-based medium. Moreover, the adaptation on mannitol did not occur at the expense of glucose, confirming the versatility of K2G30 in producing bacterial cellulose from different carbon sources. Results of this study contribute to the knowledge for designing new strategies, as an alternative to the genetic engineering approach, for bacterial cellulose production.

Extraction of Cellulose from Sugarcane Bagasse Optimization and Characterization

In this study, cellulose was extracted from sugarcane bagasse (SCB) through a convenient five-step treatment, and procedures were performed. During the alkaline curing process of the extraction of cellulose, NaOH has a concentration of (0.5, 1.5, 2.75, and 4%) and the extraction time (15, 30, and 45 min) at a constant temperature of 120°C were taken as variables and perfectly optimized by response surface methodology (RSM) for cellulose with the highest product. The optimum conditions were found to be 2.75% NaOH, 120°C, and 45 min with a cellulose yield of 73.71 ± 0.67% cellulose, 17.22 ± 0.82% hemicellulose, and 9.07 ± 0.95% lignin. Though most of the lignin was eliminated during the alkaline and dilute acid pretreatment process, the remaining lignin was removed by a solution treatment of 4% NaOH, and 21.92% H2O2 at 121°C for 44.97 min where the cellulose yield was found as 89.75 ± 0.64%, hemicellulose was 6.15 ± 0.83%, and lignin was 2.65 ± 0.66%. Morphological analysis revealed that the average diameter of the cellulose was 12.06 µm. Thermal and XRD diffraction analysis showed that the cellulose is thermally stable and has a crystallinity index of 31.63%. FTIR spectra demonstrate that cellulose was successfully extracted due to the removal of noncellulose components.

Superior separation of hemicellulose-derived sugars from eucalyptus with tropic acid pretreatment

Organic acid pretreatments can efficiently separate biomass-based hemicellulose and selectively produce hemicellulose-derived sugars. In this study, hemicellulose is separation as xylose, oligosaccharides in the tropic acid-catalyzed hydrothermal pretreatment of eucalyptus. The maximum yield of hemicellulose-derived sugars (85.78 %) with 71.25 % xylose selectivity (based on the total xylose in raw material) was achieved in the hydrolysate under optimal conditions (5 % TA, 160 ℃, 80 min). The yield of hemicellulose-derived sugar and the separation yield of hemicellulose increased by 11.06 % and 11.45 % compared with glycolic acid pretreatment in the similar severity factor. The separation yield of cellulose and lignin was decreased by 4.23 % and 0.98 %, respectively. This resulted in residual solids with higher biological stability (higher fiber crystallinity index, higher thermal stability, and higher lignin content). Therefore, higher hemicellulose separation selectivity and rich hemicellulose-derived sugars were obtained using TA pretreatment. The work would bring up a new method for biomass refining.

Modified acid pretreatment to alter physicochemical properties of biomass for full cellulose/hemicellulose utilization

Acid pretreatment of biomass decomposed hemicelluloses but could not effectively remove lignin, which hindered biomass saccharification and carbohydrates utilization. In this work, 2-naphthol-7-sulfonate (NS) and sodium bisulfite (SUL) were simultaneously added to acid pretreatment, which was found to synergistically increase hydrolysis yield of cellulose from 47.9 % to 90.6 %. Based on in-depth investigations, strong linear correlations were observed between cellulose accessibility and lignin removal, fiber swelling, CrI/cellulose ratio, cellulose crystallite size, respectively, indicating that some physicochemical characteristics of cellulose played significant roles in improving cellulose hydrolysis yield. After enzymatic hydrolysis, 84 % carbohydrates could be liberated and recovered as fermentable sugars for subsequent utilization. Mass balance illustrated that for 100 kg raw biomass, 15.1 kg xylonic acid and 20.5 kg ethanol could be co-produced, indicating the efficient utilization of biomass carbohydrates.

Cellulose in Foliage and Changes during Seasonal Leaf Development of Broadleaf and Conifer Species.

Stable isotope approaches are widely applied in plant science and many improvements made in the field focus on the analysis of specific components of plant tissues. Although technical developments have been very beneficial, sample collection and preparation are still very time and labor-consuming. The main objective of this study was to create a qualitative dataset of alpha-cellulose content of leaf tissues of arboreal species. We extracted alpha-cellulose from twelve species: Abies alba Mill., Acer pseudoplatanus L., Fagus sylvatica L., Larix decidua Mill., Picea abies (L.) Karst., Pinus sylvestris L., Quercus cerris L., Quercus petrea (Matt.) Liebl., Quercus pubescens Wild., Quercus robur L., Tilia platyphyllos Scop. and Ulmus glabra Huds. While these species show an increase in cellulose yield from bud break to full leaf development, the rates of increase in cellulose content and the duration of the juvenile phase vary greatly. Moreover, the veins display significantly higher alpha-cellulose content (4 to 11%) compared to blade tissues, which reflects their different structural and biochemical functions. A guide for the mass of sample material required to yield sufficient alpha-cellulose for a standard stable isotope analysis is presented. The additional benefits of the assessment of the mass of required sample material are reduced sample preparation time and its usefulness in preparing samples of limited availability (e.g., herbarium material, fossil samples).

Valorization of Oil Palm Empty Fruit Bunch for Cellulose Fibers: A Reinforcement Material in Polyvinyl Alcohol Biocomposites for Its Application as Detergent Capsules

Cellulose fibers isolated from oil palm empty fruit bunches (OPEFB) have been studied as a potential reinforcement for polyvinyl alcohol (PVA) biocomposite. Analysis of variance (ANOVA) showed that all three parameters—hydrolysis temperature, time and acid concentration, as well as their interactions—significantly affected the yield of cellulose. Moving Least Squares (MLS) and Multivariable Power Least Squares (MPLS) models demonstrated good fitness. The model also proved that acid concentration was the dominant parameter, supported by the Fourier transform infrared spectroscopy (FTIR) analysis. Hydrolysis using 54% acid at 35 °C and 15 min achieved the highest cellulose yield of 80.72%. Cellulose-reinforced PVA biocomposite films demonstrated better mechanical strength, elongation at break, moisture barrier properties, thermal stability and poorer light transmission rate compared to neat PVA due to the high aspect ratio, crystallinity and good compatibility of cellulose fibers. These findings suggested the potential of cellulose fibers-reinforced PVA biocomposite film as water-soluble detergent capsules.

Efficient Biomass Pretreatment Process Based on the Simple Reuse of a Low-Viscosity Ionic-Liquid Solvent System

Ionic liquids (ILs) are expensive, so it is necessary to reuse ILs; however, the reuse process is cumbersome as antisolvents are added and evaporated to regenerate ILs after each biomass pretreatment. Increasing the treatment capacity of biomass before regenerating ILs is desired; however, the high treatment capacity of biomass before IL regeneration and high lignin removal rate are a contradiction in terms. In this paper, a solution was proposed that includes pretreating biomass with a binary system composed of low-viscosity IL 1-ethyl-3-methylimidazole tetrafluoroborate ([Emim][BF4]) and l-arginine (Arg). It was shown that Arg could promote lignin dissolution and inhibit cellulose degradation in [Emim][BF4]. The system could be reused just by vacuum filtration after pretreatment without using antisolvents. After using [Emim][BF4]–Arg five times, the cumulative treatment capacity of corn straw reached 20.55%, while the total removal rate of lignin (84.94%) and the total yield of cellulose (93.23%) remained high. This method is of great significance for the industrial application of biomass pretreatment using ILs.

Green Synthesis of Bioactive Hydroxyapatite/Cellulose Composites from Food Industrial Wastes

This work aimed at conversion of worthless indurtial wastes to valuable product. Herein, bioactive composites based on bacterial cellulose (BC) and eggshell or eggshell-derived hydroxyapatite (HAp) were prepared by a green method using Gluconacetobacter xylinum bacteria. The effect of addition of eggshell (BC/Eg) and eggshell-derived HAp (BC/HAp-Eg) on the bacterial cellulose yield, biodegradation and biocompatibility was studied. For comparison, HAp derived from chemical precursors was synthesized (BC/HAp-ch). The resultant composites were characterized by XRD, FTIR, and SEM/EDX. Furthermore, the biodegradation and bioactivity were assessed in SBF, and the cell viability was studied against oral normal cells. The results showed that the productivity of BC applied HAp-derived eggshell (1.83 g/L) was higher than that of using (1.37 g/L). Interestingly, the eggshell was converted to Ca3(PO4)2 during incubation in the bacterial culture medium, while Ca3(PO4)2 was formed as a secondary phase when using either eggshell-derived HAp or chemically-derived. The in vitro bioactivity test in SBF showed that all composites were induced the formation of a bone-like apatite layer on their surface with Ca/P ratio, 1.49, 1.35, and 1.41 for BC/Eg, BC/HAp-ch, and BC/HAp-Eg, respectively, near to the ratio in the natural HAp. Finally, the in vitro cell viability test was confirmed good biocompatibility against the composites. However, at high sample concentration (250 µg/mL), BC/HA-Eg showed the higher cell viability (95.2%) than that of BC/Eg (80.5%) and BC/HA-ch (86.2%). In conclusion, eggshell waste could be used directly with bacterial cellulose to produce bioactive composites without the need to convert it to HAp which reduced the cost of production and thus has a higher economic return. Obiviously, eggshell waste can act as calcium, organic matter source, pH preservation, nuterilizing agent along with potential instead of costly buffering agent in the BC culture medium and further for increased the BC production.

Novel Two-Step Process in Cellulose Depolymerization: Hematite-Mediated Photocatalysis by Lytic Polysaccharide Monooxygenase and Fenton Reaction.

To transform cellulose from biomass into fermentable sugars for biofuel production requires efficient enzymatic degradation of cellulosic feedstocks. The recently discovered family of oxidative enzymes, lytic polysaccharide monooxygenase (LPMO), has a high potential for industrial biorefinery, but its energy efficiency and scalability still have room for improvement. Hematite (α-Fe2O3) can act as a photocatalyst by providing electrons to LPMO-catalyzed reactions, is low cost, and is found abundantly on the Earth’s surface. Here, we designed a composite enzymatic photocatalysis–Fenton reaction system based on nano-α-Fe2O3. The feasibility of using α-Fe2O3 nanoparticles as a composite catalyst to facilitate LPMO-catalyzed cellulose oxidative degradation in water was tested. Furthermore, a light-induced Fenton reaction was integrated to increase the liquefaction yield of cellulose. The innovative approach finalized the cellulose degradation process with a total liquefaction yield of 93%. Nevertheless, the complex chemical reactions and products involved in this system require further investigation.

The Effect of Sodium Hydroxide (NaOH) Concentration on Oil Palm Empty Fruit Bunch (OPEFB) Cellulose Yield

Cellulose is one of the renewable resources and has become a core target among researchers in recent times to make sustainable biopolymer-based materials. The extraction of cellulose from oil palm empty fruit bunch (OPEFB) by using 4%-13% sodium hydroxide (NaOH) and undergoes bleaching process with 1.7% sodium chlorite solutions (NaOCl) has been done in this study. The maximum yield of cellulose (89.78%) was obtained with 4% NaOH. The effectiveness of NaOH treatment to obtain the cellulose was reflected in Fourier Transform Infrared (FTIR) analysis where the frequency of the C=C aromatic group of lignin resonated around 1600 cm−1 to 1590 cm−1 has been reduced in alkali treatment and disappeared after the bleaching treatment. Meanwhile, the peak for -OH group of cellulose and the -CH methylene group was observed at around 3330 cm−1 and 2900 cm−1 respectively. It was found that increasing the NaOH concentration increased the yield of cellulose to some extent.

Efficient removal of residual lignin from eucalyptus pulp via high-concentration chlorine dioxide treatment and its effect on the properties of residual solids

In fact, effectively removing lignin from pulp fibers facilitates the conversion and utilization of cellulose. In this study, the residual lignin in eucalyptus pulp was separated using a high concentration of chlorine dioxide. The effects of chlorine dioxide dosage, temperature, and time on lignin removal were investigated. The optimal conditions are chlorine dioxide dosage 5.0%, reaction temperature 40 °C, and reaction time 30 min. The lignin removal yield is 88.21%. The removal yields of cellulose and hemicellulose are 2.28 and 17.00%, respectively. The treated eucalyptus pulp has higher fiber crystallinity and thermal stability. The carbon content on the fiber surface is significantly reduced. The results show that lignin is removed by efficient oxidation, and the degradation of carbohydrates is inhibited using high concentrations of chlorine dioxide at low temperatures and short reaction times. This provides theoretical support for high value conversion of cellulose.