Pretreatment Of Bamboo Research Articles

Preparation and characterization of lignin containing cellulose nanofiber from moso bamboo via acidified choline chloride/ethylene glycol pretreatment combined with homogenization

Lignin is one of the main components of lignocellulose, which is conducive to controlling and optimizing the performance of cellulose nanofiber. In the present work, lignin containing cellulose nanofiber (LCNF) was prepared from moso bamboo by acidified choline chloride/ethylene glycol (acidified ChCl/EtG) pretreatment combined with high-pressure homogenization. The cellulose-rich residue with gradient lignin retention (9.10–31.12%) was obtained from bamboo pretreatment under different reaction conditions. The residue was nanofibrillated into LCNF via high-pressure homogenization. The results showed that the width of LCNF samples was 6–30 nm and its width was tunable by adjusting the lignin content in cellulose-rich residue. Meanwhile, the lignin was evenly distributed in the LCNF suspension, endowing LCNF with UV shielding capability. Moreover, the LCNF suspension was stable at concentrations above 0.1 wt%, which was prone to long-term preservation and utilization. The presence of a certain amount of lignin was also able to enhance the mechanical properties of LCNF films, which can provide a prospective future for bamboo and LCNF valued-added utilization.

Pretreatment of bamboo with choline chloride-lactic acid integrated with calcium chloride hydrates deep eutectic solvent to boost bioconversion for ethanol production

Deep eutectic solvent has been recognized as a green and nascent solvent to overcome the recalcitrance of lignocellulosic biomass for effective valorization. In this study, choline chloride (ChCl) and lactic acid (LA) at molar ratio of 1:2 integrating with 1–10 wt% calcium chloride hydrates (CaCl2·6H2O) deep eutectic solvents (DESs) were applied to pretreat bamboo. With increasing of calcium chloride hydrates dosage, maximum removals of lignin and xylan were obtained as 84.7% and 91.0%, respectively. DESs pretreatments also induced degradation of cellulose, declining CrI, DP and hydrophobicity of cellulosic samples. With change of structural features, enzyme accessibility and affinity of substrates increased and prompted bioconversion of bamboo. Feasible bioconversion was achieved by pretreating bamboo with ChCl-LA-5% CaCl2∙6 H2O at 120 ºC for 3 h. 0.149 g/g glucose and 0.128 g/g ethanol were produced from the substrate via enzymatic hydrolysis and simultaneous saccharification and fermentation, respectively. Pearson correlation coefficients (PCCs) indicated that lignin and xylan removal, enzyme accessibility, DP and hydrophobicity showed greatly strong relationship between bioconversion of substrate (all PCCs>0.8). Ratio of crystalline index to cellulose content showed strong relationship between bioconversion with − 0.71 and − 0.72 PCCs for enzymatic digestibility and ethanol production, respectively. Relationship between enzyme adsorption and bioconversion of substrates was moderate strength (0.57 and 0.42 for enzymatic digestibility and ethanol production, respectively). The recycling experiment indicated that ChCl-LA-5% CaCl2∙6 H2O retained acceptable pretreatment performance after twice recycles. Taking all cycles of ChCl-LA-5% CaCl2∙6 H2O into consideration, the solid to liquid ratio reduced from 1:20–1:7.35.

Effects of different pretreatments combined with steam explosion on the properties of bamboo fibers

Bamboo pretreatment is a key technology for the preparation of bamboo fibers (BFs) for composites. This study examined the properties of BFs prepared by steam explosion (SE) BFs following pretreatment by enzyme, alkali, and salt. The microstructure, functional groups, crystallinity, and surface chemical elements of BFs were characterized by environmental scanning electron microscope (ESEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results indicated that bamboo could be separated into fiber bundles through SE after pretreatment. The separation of BFs pretreated by enzyme and alkali were better, but colloid remained and was able to stick the fibers together. Through performing different pretreatments before SE, the lignin and hemicellulose of BFs were partially removed, and alkali pretreatment had the best effect on lignin removal. The crystal structure of the BFs did not change significantly, and the crystallinity of BFs was highest at 2 MPa and 6 min when pretreated by alkali. The XPS results showed that the effect of alkali pretreatment at 2 MPa for 6 min was the best.

Alkaline deacetylation-aided hydrogen peroxide-acetic acid pretreatment of bamboo residue to improve enzymatic saccharification and bioethanol production

Bamboo pretreatment with alkaline deacetylation-aided hydrogen peroxide-acetic acid (HPAC-NaOH) was investigated for producing high-value-added products. Comparing with HPAC pretreated D. sinicus, the post-treatment of alkaline deacetylation resulted in higher glucose yield of 91.3% and ethanol concentrations of 17.20 g/L, increased by about 20–27%. A strong negative correlation between the content of acetyl with cellulose accessibility and enzymatic hydrolysis yield was showed. The deacetylation of HPAC-DS contributed to the increase of cellulase adsorption capacities in substrates and the variations of hydrophilicity, cellulose crystallinity, and degree of polymerization, which can generate highly reactive cellulosic materials for enzymatic saccharification to produce bioethanol. The HPAC-NaOH pretreatment can provide a promising approach to improve the bioconversion of bamboo to biofuels, and has broad space for the biorefinery of bamboo in the south of China.

Optically Transparent Bamboo with High Strength and Low Thermal Conductivity

The objective of this study is to convert bamboo into a transparent material with great optical transmittance and good strength. Bamboo has a much faster regeneration rate than wood, but its high density and high extractive content make it challenging to produce transparent products. This study presents a simple and effective approach that could address this challenge. Pretreatment of bamboo with low concentration sodium hydroxide greatly improved the preparation efficiency of transparent bamboo. The transparent bamboo with a thickness of 1 mm and cellulose volume fraction of 22% made from the pretreated bamboo exhibited an improved total optical transmissivity up to 80%, which was 60% higher than that of untreated bamboo. Compared to transparent wood (TW), although the transmissivity of transparent bamboo was slightly lower, its mechanical strength was almost doubled. Besides, the developed transparent bamboo exhibited a low heat conductivity of 0.203 W m-1 K-1, being about 10% lower than that of TW (0.225 W m-1 K-1) and approximately 80% lower than that of common glass material (0.974 W m-1 K-1). The transparent bamboo would significantly enhance energy-saving performance, being a promising alternative to traditional glass.

Pretreatment of Bamboo by Ammonium Sulfite for Efficient Enzymatic Hydrolysis

In order to find out the potential effect of ammonium sulfite pretreatment on bamboo for efficient enzymatic saccharification, various ammonium sulfite loadings were conducted to pretreat bamboo at 180 °C for 1–8 h with the solid–liquid ratio of 1:6, respectively. The results verified that ammonium sulfite pretreatment could effectively disrupt the recalcitrance of bamboo and create highly enzymatic hydrolysis sugar yield for further utilization. The contents of lignin in the substrates decreased significantly (from 22.94% to 1.21%) after pretreated and the higher lignin removal with higher chemical loading and longer reaction time during pretreatment. The cellulose-to-glucose conversion yield of pretreated bamboo substrates could achieve almost 100% within 48 h by enzymes loading of 15 FPU of cellulase and 30 IU of β-glucosidase per gram glucan. Therefore, ammonium sulfite pretreatment is argued to be a potential alternative technology for pretreatment of bamboo.

Alkali and glycerol pretreatment of West African biomass for production of sugars and ethanol

KOH (1%) and glycerol (20–40%) pretreatment of bamboo, rubber, elephant grass and nSiam weed were investigated with respect to biomass composition, enzymatic hydrolysis and ethanol fermentation. Delignification was higher under alkaline environment and increased considerably with temperature (25-121 °C). Lignin removal had a positive effect on biomass digestibility, sugars production and ethanol yield. The highest sugar and ethanol yields were observed for KOH pretreatment (121 °C, 1 h) on elephant grass which also recorded the highest delignification (67.5%) and consequently the lowest solids recovery (59.5%). The grass gave the highest yield on glucose (19 g/100 g raw material), xylose (8.2 g/100 g raw material) and ethanol (9.8 g/100 g raw material) under KOH pretreatment (121 °C, 1 h). The elephant grass has great potential to be used as a major energy crop in Africa in a biorefinery where production of sugars, ethanol and other valuable biochemicals are optimised.

Cooking with active oxygen and solid alkali facilitates lignin degradation in bamboo pretreatment

By using HSQC NMR, delignification of the CAOSA process was described, which paves the way for developing new eco-friendly pulping technology.

Enhancing lignin degradation by Mn2+ ion supplementation to assist enzymatic hydrolysis of cellulose in a two-stage pretreatment of bamboo

Abstract: It is of great significance to reveal a key agent to improve the efficiency of conversion of lignocellulosic biomass to fermentable sugars for the production of bioethanol. This study investigated a two-stage pretreatment of bamboo comprising a microbial treatment using Ceriporiopsis sp. followed by a hydrothermal treatment to facilitate the process with Mn2+ as an accelerator. The effects of Mn2+ nutritional addition on ligninolytic activity, lignin degradation, total weight loss, pulp yield, sugar yield and sugars in the soluble fraction were examined. The results showed that the time required for the incubations supplemented with Mn2+ to achieve sufficient lignin degradation and sugar yield from both the pulp and soluble fractions was significantly shortened, whereas all three ligninolytic activities were significantly decreased. The enzyme activity varied according to the presence of Mn2+, although the amount and species of the expressed protein are similar. Considering the cost, microbial treatment with a one-time fed-batch supply of metal nutrition (MnSO4) was the most preferable contribution to hydrothermal pretreatment, resulting in 19.7% lignin degradation, 66.7% pulp yield and 26.1% sugar yield over a period of 21 d. It was proven that microbial treatment by solid state incubation with Mn2+ nutrition has the potential to be a low-cost, environmentally friendly alternative to chemical approaches. Keywords: hydrolysis, fungi, Mn2+ ion, pretreatment, bamboo, Ceriporiopsis sp. DOI: 10.3965/j.ijabe.20171003.2991 Citation: Liu J, Gan L H, Long M N. Enhancing lignin degradation by Mn2+ ion supplementation to assist enzymatic hydrolysis of cellulose in a two-stage pretreatment of bamboo. Int J Agric & Biol Eng, 2017; 10(3): 175–184.

A biorefinery scheme to fractionate bamboo into high-grade dissolving pulp and ethanol

BackgroundBamboo is a highly abundant source of biomass which is underutilized despite having a chemical composition and fiber structure similar as wood. The main challenge for the industrial processing of bamboo is the high level of silica, which forms water-insoluble precipitates negetively affecting the process systems. A cost-competitive and eco-friendly scheme for the production of high-purity dissolving grade pulp from bamboo not only requires a process for silica removal, but also needs to fully utilize all of the materials dissolved in the process which includes lignin, and cellulosic and hemicellulosic sugars as well as the silica. Many investigations have been carried out to resolve the silica issue, but none of them has led to a commercial process. In this work, alkaline pretreatment of bamboo was conducted to extract silica prior to pulping process. The silica-free substrate was used to produce high-grade dissolving pulp. The dissolved silica, lignin, hemicellulosic sugars, and degraded cellulose in the spent liquors obtained from alkaline pretreatment and pulping process were recovered for providing high-value bio-based chemicals and fuel.ResultsAn integrated process which combines dissolving pulp production with the recovery of excellent sustainable biofuel and biochemical feedstocks is presented in this work. Pretreatment at 95 °C with 12% NaOH charge for 150 min extracted all the silica and about 30% of the hemicellulose from bamboo. After kraft pulping, xylanase treatment and cold caustic extraction, pulp with hemicellulose content of about 3.5% was obtained. This pulp, after bleaching, provided a cellulose acetate grade dissolving pulp with α-cellulose content higher than 97% and hemicellulose content less than 2%. The amount of silica and lignin that could be recovered from the process corresponded to 95 and 77.86% of the two components in the original chips, respectively. Enzymatic hydrolysis and fermentation of the concentrated and detoxified sugar mixture liquor showed that an ethanol recovery of 0.46 g/g sugar was achieved with 93.2% of hydrolyzed sugars being consumed. A mass balance of the overall process showed that 76.59 g of solids was recovered from 100 g (o.d.) of green bamboo.ConclusionsThe present work proposes an integrated biorefinery process that contains alkaline pre-extraction, kraft pulping, enzyme treatment and cold caustic extraction for the production of high-grade dissolving pulp and recovery of silica, lignin, and hemicellulose from bamboo. This process could alleviate the silica-associated challenges and provide feedstocks for bio-based products, thereby allowing the improvement and expansion of bamboo utilization in industrial processes.

Pretreatment of Bamboo by Ferric Chloride and Ferric Sulfate for Enzymatic Hydrolysis

Pretreatment of Bamboo by Ferric Chloride and Ferric Sulfate for Enzymatic Hydrolysis

Impact of Dilute Sulfuric Acid Pretreatment on Fermentable Sugars and Structure of Bamboo for Bioethanol Production

Moso bamboo (Phyllostachys edulis) is an important source of lignocellulosic materials because of its fast growth, its vegetative propagation, and its easy harvesting. The pretreatment of bamboo with dilute sulfuric acid and the effects on its chemical components and enzymatic hydrolysis were studied, in addition to the fibrous structural properties of pretreated residues by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The results showed that dilute sulfuric acid pretreatment primarily hydrolyzed hemicelluloses and resulted in enhanced cellulose and lignin content in the pretreated solids. The maximum yield of hemicellulose recovery was 81.42% when pretreated with 1.00% sulfuric acid at 150 °C for 30 min, and the enzymatic hydrolysis yield was 79.45% when hydrolyzed for 72 h with an enzyme loading of cellulase 40 FPU/g of cellulose. Under these conditions, the overall sugar yield was 83.36% (cellulose and hemicellulose), with a total of 67.11 g fermentable sugars from 100 g dry bamboo. The results indicated that Moso bamboo underwent considerable changes in its chemical composition and physical properties after acid pretreatment, such as the removal of hemicellulose and lignin, an increase in specific surface area and pore volume, and exposure of internal structure, which enhances the enzymatic hydrolysis of Moso bamboo.

Effects of Dilute Alkali Pretreatment on Chemical Components and Fermentable Sugars and Structure of Bamboo

The pretreatment of bamboo with dilute alkali and the effects on chemical components and enzymatic hydrolysis were studied, and the fiber structural properties of pretreated residues were studied with Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). The results showed that dilute alkali was highly effective in delignification of the biomass, reducing the lignin content by 50-70%. Bamboo solid recovery was 74.40%, and cellulose, hemicellulose and lignin content were 60.02%, 25.93% and 9.08%, respectively, when pretreated with 1.0% sodium hydroxide, with a solid-liquid ratio of 1:10 at 100 °C for 40 min. Under the conditions, the pretreated residue was hydrolyzed for 72 h with cellulose and xylanase dosage 40 FPU/g cellulose, and the hydrolysis yield of cellulose was 81.38% and that of hemicelluloses was 84.78%, resulting in a total of 66.74 g fermentable sugars from 100 g dry bamboo. The SEM pictures indicated that the biomass structure was deformed and its fibers were exposed, and FTIR results verified the lignin removal by the pretreatment.

Lab-scale co-firing of virgin and torrefied bamboo species Guadua angustifolia Kunth as a fuel substitute in coal fired power plants

Bamboo is a potential sustainable biomass source for renewable heat and power production as it presents common fuel characteristics with other biomass feedstocks regarding heating value and chemical composition. This paper presents an evaluation of the combustion behaviour of the bamboo species Guadua angustifolia Kunth, virgin as well as torrefied, in blends with coal or pure, comparing with other biomass feedstocks such as wood and herbaceous biomass. The bamboo pre-treatment and the combustion experiments were carried out at dedicated installations at ECN, including a laboratory scale batch torrefaction reactor and a combustion simulation test facility. The results on combustion and co-firing reveal that in terms of fouling, the untreated bamboo shows behaviour closer to herbaceous biomass rather than to wood, with specific fouling factors of wood, bamboo and herbaceous biomass of 0.91·10−3, 2.9·10−3, 3.1·10−3 K·m2·W−1·g−1 respectively. Dry torrefaction improves its physical properties by increasing the density and grindability without improving significantly its fouling behaviour while the fouling behaviour of wet torrefied bamboo is similar to woody biomass; the specific fouling factors of dry torrefied and wet torrefied bamboo are 2.4·10−3 and 0.89·10−3 K·m2·W−1·g−1 respectively. The fouling behaviour of biomass and coal blends lies between the fuels of the blend. Alternative bamboo species were evaluated using the alkali index Ai based on their fuel composition. It appears that the fouling behaviour of alternative species is better than for G. angustifolia, therefore these should be further analysed.

Study on the Pretreatment of the Preparation of Bamboo Fiber and its Bleaching Technology

Bamboo fiber is a new natural green environmental protection fiber material with good characteristics of good permeability, unique elasticity, transient absorption, antibacterial, odor resistance and stronger vertical and horizontal intensity. Bamboo pretreatment can improve the biological degumming efficiency of bamboo lignin, reduce microbial degumming time, and reduce production costs. The results show that the removal efficiency of pectin, hemicelluloses and lignin are better after the pretreatment of bamboo mercerization. Through orthogonal experiments, it can be got the optimum combination of bamboo fiber alkali cooking process is A2-B2-C2-D1, namely: concentration of NaOH is 6.0g / L, its time is 60min, temperature 100 °C, and bath ratio 1:20. In these four factors, the greatest impact on the removal of lignin is temperature, followed by is degumming time, then the concentration of alkali, and the bath ratio is the smallest. The best conditions of bamboo fiber bleaching is: hydrogen peroxide 25 ~ 35g / L, temperature 30 ~ 40 °C, treatment 45 ~ 60min. The process of the pretreatment of bamboo is: clip → Roll → high-pressure steaming → roll→ immersion separation → alkali leaching treatment→ scouring → rolling combing →washing→ drying →crude fiber → bleaching.

Enhanced bioavailability of paclitaxel by bamboo concentrate administration

The purpose of this study was to investigate the effect of a cotreatment of bamboo concentrates (Jukcho solution; 0.75, 1.5, and 3.0 mL/kg) with the chemotherapeutic agent paclitaxel on the bioavailability of orally administered paclitaxel (50 mg/kg) in rats. The effect of a pretreatment of bamboo concentrates (1.5 and 3.0 mL/kg for 1.0 h or a consecutive 3 day) was also examined. The paclitaxel plasma concentrations of rats orally administered paclitaxel plus bamboo concentrates (coadministration, 3.0 mL/kg and pretreatment, 1.5 and 3.0 mL/kg) were significantly higher than those of rats treated with paclitaxel alone. Plasma concentrations of paclitaxel in groups pretreated with bamboo concentrates for 3 day were markedly higher than those of a paclitaxel control group at the measured time points. The areas under plasma concentration-time curves (AUCs) of paclitaxel in groups pretreated with bamboo concentrates were elevated and the absolute bioavailability (AB%) and relative bioavailability (RB%) of paclitaxel were also significantly higher than those in the control group. The peak concentration (Cmax), half-life (t1/2), and the elimination rate constant (Kel) of paclitaxel after 3 day of pretreatment with bamboo concentrates were also significantly higher than those in the control, but the time required to reach the maximum plasma concentration (Tmax) of paclitaxel was unaffected by the bamboo concentrates. Western blot analyses demonstrated that the level of CYP3A4 was increased in the livers of rats treated orally with paclitaxel, but this was reversed by pretreating with bamboo concentrates. These results show that bamboo concentrates enhance the bioavailability of orally administered paclitaxel and this effect may be associated with a diminished expression of CYP3A4 in the liver.

Lignin extraction and recovery in hydrothermal pretreatment of bamboo

A significant amount of lignin and hemicellulose are dissolved in the hydrothermal treatment of biomass. The hemicellulose can be recovered and utilized for value-added products. The dissolved lignin can undergo depolymerization and condensation reactions, and interferes with the separation and purification process for hemicellulose recovery. This paper investigated the behavior of the lignin extracted from the hydrothermal pretreatment of bamboo and its contributions to the physical characteristics of the hydrolysate. It was found that the turbidity of the hydrolysate was strongly associated with the lignin fragments and suspended long chain hemicelluloses. As the lignin depolymerization and condensation reactions occurred simultaneously, the dissolved lignin fractions in the hydrolysate increased first and then decreased. The molecular weight (MW) of the dissolved lignin fragments ranged from 3342 ~ 5611 g/mol, with mainly guaiacyl (G) and syringyl (S) unit in the structure.