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Bamboo is a perennial rapid-growing plant that is given preference for renewable biosources for biofuels and bio-based chemical conversion. Bamboos are rich in cellulose and have highly recalcitrant biomass due to high lignin. Bamboo is abundantly available in Northeastern India and can be utilized as a feedstock biofuels. Here, we evaluated the pretreatment of bamboo residues Dendrocalamus strictus with different concentrations of alkali, hydrogen peroxide, and alkaline hydrogen peroxide and its influence on biomass digestibility for enhancement of sugar recovery with Celic C cellulase enzyme blend. Enzymatic hydrolysis data indicated untreated raw biomass showed a digestibility of 40% after 48 h of incubation. The biomass pretreated with alkali showed a maximum digestibility of 61% obtained from 10% loaded with 0.5% w/v NaOH. Pretreatment of the bamboo with H2O2 shows a maximum digestibility of 75% from biomass loaded with 1% w/v of H2O2. Combinational pretreatment of alkaline hydrogen peroxide showed a maximum efficiency of biomass digestibility of 83% attained from biomass loaded with 1% w/v NaOH-H2O2. Crystallinity index (CrI) analysis showed that CrI increased from 64% to 70.75% in pretreated biomass. FTIR and SEM analysis show changes in functional groups, morphology, and surface of biomass in pretreated biomass. Compositional analysis shows that 68% of lignin removal is obtained from alkaline hydrogen peroxide pretreatment. Cellulose content increased from 52% to 65%, and hemicellulose decreased from 18.6% to 8.6%. Results indicated that the potential possibility of bamboo waste biomass as feedstock for biorefinery products and alkaline hydrogen peroxide pretreatment methods is an efficient strategy for sugar recovery for bioethanol production. [ABSTRACT FROM AUTHOR]

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This study investigated the biphasic phenoxyethanol–citric acid (PECA) pretreatment for bamboo residues (BRs) and its corresponding effects on the enzymatic hydrolysis performance. It is found that increasing the concentration of citric acid in the pretreatment system from 2.5% to 15% greatly enhanced the delignification and xylan removal for BRs. Consequently, the enzymatic hydrolysis yield of pretreated BRs significantly enhanced, increasing from 12.4% to 58.2% and 28.0%72.4% when the concentration of citric acid was increased from 2.5% to 15.0% at 160°C and 170°C, respectively. The characterization results from cellulose crystallinity, accessibility, and hydrophobicity of pretreated bamboo residues indicated that their changes possessed a beneficial performance on the enzymatic hydrolysis yield, which could result from the synergistic removal of lignin and xylan. The Chrastil model analysis showed that pretreatment at higher conditions resulted in the pretreated BRs possessing weaker diffusion resistance for cellulase, which is attributed to its higher enzymatic hydrolysis yield.

Bamboo is a perennial rapid-growing plant that is given preference for renewable biosources for biofuels and bio-based chemical conversion. Bamboos are rich in cellulose and have highly recalcitrant biomass due to high lignin. Bamboo is abundantly available in Northeastern India and can be utilized as a feedstock biofuels. Here, we evaluated the pretreatment of bamboo residues Dendrocalamus strictus with different concentrations of alkali, hydrogen peroxide, and alkaline hydrogen peroxide and its influence on biomass digestibility for enhancement of sugar recovery with Celic C cellulase enzyme blend. Enzymatic hydrolysis data indicated untreated raw biomass showed a digestibility of 40% after 48 h of incubation. The biomass pretreated with alkali showed a maximum digestibility of 61% obtained from 10% loaded with 0.5% w/v NaOH. Pretreatment of the bamboo with H2O2 shows a maximum digestibility of 75% from biomass loaded with 1% w/v of H2O2. Combinational pretreatment of alkaline hydrogen peroxide showed a maximum efficiency of biomass digestibility of 83% attained from biomass loaded with 1% w/v NaOH-H2O2. Crystallinity index (CrI) analysis showed that CrI increased from 64% to 70.75% in pretreated biomass. FTIR and SEM analysis show changes in functional groups, morphology, and surface of biomass in pretreated biomass. Compositional analysis shows that 68% of lignin removal is obtained from alkaline hydrogen peroxide pretreatment. Cellulose content increased from 52% to 65%, and hemicellulose decreased from 18.6% to 8.6%. Results indicated that the potential possibility of bamboo waste biomass as feedstock for biorefinery products and alkaline hydrogen peroxide pretreatment methods is an efficient strategy for sugar recovery for bioethanol production.

Bamboo is considered a renewable energy bioresource for solving the energy crisis and climate change. Dendrocalamus branddisii (DB) was first subjected to sulfomethylation reaction at 95°C for 3 h, followed by Fenton oxidation pretreatment at 22°C for 24 h. The synergistic effect of combined pretreatment dramatically improved enzymatic digestibility efficiency, with maximum yield of glucose and ethanol content of 71.11% and 16.47 g/L, respectively, increased by 4.7 and 6.11 time comparing with the single Fenton oxidation pretreatment. It was found that the hydrophobicity of substrate, content of surface lignin, degree of polymerization, and specific surface area have significant effects on the increase of enzymatic saccharification efficiency. It also revealed that sulfomethylation pre-extraction can improve the hydrophilicity of lignin, leading to the lignin dissolution, which was beneficial for subsequent Fenton pretreatment of bamboo biomass. This work provides some reference for Fenton oxidation pretreatment of bamboo biomass, which can not only promote the utilization of bamboo in southwest China, but also enhances the Fenton reaction in the bamboo biorefinery.

The effective promotion of delignification (67.6%) and xylan removal (44.8%) from bamboo residues using a 2-phenoxyethanol/sodium hydroxide solution (P/A) system is demonstrated, while simultaneously enriching oligosaccharides contents of the pre-hydrolysate to 10.2 g/L. Increasing the P/A ratio from 0:1 to 4:1 improves the enzymatic digestibility of the substrates from 55.7% to 70.1% at 100 °C and from 73.8% to 83.7% at 120 °C. Furthermore, partial correlation analysis demonstrates that the physiochemical properties, including delignification, xylan removal, and crystallinity, show a significant positive correlation with enzymatic hydrolysis efficiency. Higher temperatures and P/A ratios during alkaline biphasic pretreatment promote the shrinkage of plant cells and delignification, with temperature being a particularly significant driver. These findings provide valuable insights into the alkaline and biphasic pretreatment of biomass and facilitate the optimization of the bio-refining system. [Display omitted] [ABSTRACT FROM AUTHOR]

Copyright of Chemistry & Industry of Forest Products is the property of Chemistry & Industry of Forest Products Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

• Exploring the economic feasibility of biphasic pretreatment technology. • High-value lignin-based adhesive can bring significant economic benefits. • Trade-offs between product yield and economic performance are revealed. • Key drivers of economic feasibility are identified. This study conducted a techno-economic analysis to assess the economic feasibility of a biorefinery converting bamboo residues to bioproducts via phenoxyethanol-acid pretreatment. The analysis is integrated with a rigorous process simulation model with the support of experiment data. The bioproducts include ethanol or polylactic acid (PLA), with lignin-based wood adhesive as the byproduct. The minimum selling price (MSP) is $515-$819 per t ethanol and $1,512-$1,842 per t PLA when biphasic treatment is deployed, compared to the MSP of $2,318-$2,721 per t ethanol and $2,859-$3,211 per t PLA for no biphasic pretreatment. Adopting a ratio of 1:1 phenoxyethanol: acid solution (1%) in pretreatment decreases the final product yield but leads to lower MSP than 4:1 phenoxyethanol: acid solution (1%) due to lower phenoxyethanol consumption. A sensitivity analysis identifies the key drivers of reducing MSP, including increasing economic gain from the lignin-based wood adhesive, lowering the phenoxyethanol cost, and expanding plant capacity. [ABSTRACT FROM AUTHOR]

To investigate co-pyrolysis properties and mechanisms of bamboo residues (BR) and disposable face mask (DFM), the blends of BR and DFM with mass ratios of 100%:0%, 95%:5%, 90%:10%, 85%:15%, 80%:20%, and 0%:100% were pyrolyzed using thermogravimetric analyzer coupled with a Fourier-transform infrared (TG-FTIR). Results showed that fundamental characteristics of BR and DFM were significantly different, although volatile matters were the main components of DFM (98.91%) and BR (79.63%). Higher heating value of BR (18.45 MJ/kg) was significantly lower than 45.54 MJ/kg of DFM. BR and DFM had one pyrolysis stage, while the blends owned two stages. Synergistic reaction occurred at the second pyrolysis stage, and BR promoted the pyrolysis of DFM. Gaseous products included H 2 O, CH 4 , CO 2 , CO, C=O, C–O–C, CH 4 , C=C, and C–H groups. KAS and FWO methods were suitable to calculate kinetic parameters. BR had the lowest activation energy of 216.13 kJ/mol while DFM had the highest 303.26 kJ/mol. The H-donor radicals of DFM volatiles enhanced the cracking of aromatic compounds in BR while suppressing cyclization and aromatization reactions contributed to the formation of char. The solid, liquid and gaseous products of co-pyrolysis could be used as fuels and chemicals to value-added utilize DFM. They have a potential for commercial development of future. [Display omitted] • BR and DFM have one pyrolysis stage, while the blends own two stages. • BR promotes the pyrolysis of DFM. • Synergistic reaction occurs at the second pyrolysis stage. • KAS and FWO methods are suitable to calculate kinetic parameters. • Free radical reaction mechanism illustrates synergistic reaction. [ABSTRACT FROM AUTHOR]

[Display omitted] • Producing ethanol, PLA, and wood adhesive from bamboo residues. • Exhibiting the environmental benefits of biphasic pretreatment technology. • Trade-off between product yield and environmental impacts are revealed. • High-value lignin-based adhesive can bring environmental benefits. • Key drivers of environmental performance are identified. Utilizing bamboo residues to produce decarbonization energy products or materials diverts wastes from low-value treatment and supports the circular bioeconomy at the same time. This study develops a cradle-to-grave life-cycle assessment (LCA) for a biorefinery converting bamboo residues into bioproducts (ethanol, polylactic acid (PLA), and bio-based wood adhesive) in China. To combat the low enzymatic hydrolysis performance of bamboo residues and valorize the lignin, this study adopts a biphasic pretreatment by coupling phenoxyethanol and sulfuric acid solution (1%) to achieve high fermentable sugar production. The LCA study is coupled with a process simulation for an industrial-scale biorefinery based on the experimental data. Our results show that the life-cycle Global Warming Potential (GWP) is 17.0–32.1 gCO 2 e/MJ for ethanol cases and 3.2–3.7 kgCO 2 e/kg for PLA cases, when biphasic pretreatment is adopted. The lower GWP values are achieved by using 1:1 phenoxyethanol: acid solution, though it has a lower product yield than 4:1 phenoxyethanol: acid solution cases. Without biphasic pretreatment, the GWP is 135.8 gCO 2 e/MJ ethanol and 4.4 kgCO 2 e/kg PLA. For the perspective of treating 1 dry t bamboo residues, with biphasic pretreatment, the GWP is −174 to −66 kgCO 2 e for ethanol cases and −542 to −432 kgCO 2 e for PLA cases. The lower GWP is also from using 1:1 phenoxyethanol: acid solution (1%). These GWP ranges are lower than conventional landfilling (2969 kgCO 2 e) and landfilling with landfill gas recovery (−28 kgCO 2 e). [ABSTRACT FROM AUTHOR]

Abstract This study investigated the physical and mechanical properties of six groups of bamboo–wood composites (BWC) made from bamboo and wood wastes, which are produced from the industry processing in Taiwan. Results obtained from non-destructive testing (NDT) indicated that the boards made with 100% bamboo residues (Group B) revealed higher ultrasonic-wave velocity (V u) and tap tone sound velocity (V t) than other BWC boards. Both V u and V t of composite boards were proportional to the ratio of bamboo residues contains. Three-layer composites made with bamboo/wood/bamboo residues at 1:2:1 ratio (Group B/2W/B) had the highest specific strength as well as modulus of elasticity (MOE) and modulus of rupture (MOR) among all the composites. B/2W/B composite board had structural characteristics similar to those of medium-density fiberboards (MDF) and particleboards; thus, it might have better compression resistance than other types of boards. B/2W/B composite board also had the highest screw holding strength (SHS); next was the boards composed entirely of woody wastes (Group W). The results obtained from analysis of water absorption rate (WA%) show a positive correlation with porous bamboo contents; meanwhile, wood chips have higher water-absorption swelling rate than bamboo residues. Hence, it showed greater change in thickness swelling coefficient (TS%) and volume swelling coefficient (S%).

This study focused on the assessment of gas emissions and bioenergy potential of the combustions of bamboo leaves (BL), shoot leaves (BSL) and branches (BB) in the air atmosphere. The main combustion stage of the three residues occurred at between 200 and 600 °C, with three peaks of mass loss. The pattern of mass loss rate was BSL > BB > BL, with BSL having the best combustion characteristic parameters. The main evolved gases were CO 2 and H 2 O at between 200 and 600 °C. Organic gaseous compounds were decomposed in the range of 200–400 °C. Air pollutants were produced in the range of 200–500 °C. N-containing gas pollutants were 0.01–0.1 times CO 2 , while SO 2 was produced in a very small amount. BL produced more gas pollutants than did BSL and BB, while the controls over the gas pollutants should be more concentrated in the range of 200–400 °C. The joint optimizations of derivative thermogravimetry, differential scanning calorimetry, remaining mass, and conversion degree showed 653.2 °C and 5 °C/min as the optimum operational conditions for bioenergy utilization, while BB performed as the best feedstock. Among three iso-conversion methods used to estimate activation energy, Flynn-Wall-Ozawa led to best correlation. The Coats-Redfern method pointed to the second order reaction model (f (α) = (1− α)2) as the most likely reaction mechanism. Overall, the bamboo residues were promising as the environmentally friendly and renewable feedstock. Our findings can provide the basis for bioenergy generation, pollution control, and optimal efficiency when the industrial-scale combustions of the bamboo residues are adopted. Image 1 • Combustion behaviors of three bamboo residues were compared for four heating rates. • Their bioenergy generation potential was rated as BSL > BB > BL. • Gas products were mostly CO 2 and H 2 O, and rarely NO x and SO 2. • Kinetic triplets indicated the different mechanisms of the residues. • Four responses were jointly optimized using temperature, heating rate and residue type. [ABSTRACT FROM AUTHOR]

SO 2 -ethanol-water (SEW) is a promising pretreatment for improving enzymatic digestibility of biomass through simultaneously removing hemicellulose and lignin. In this work, SEW pretreatment was performed at different cooking times (10 min–60 min) and different SO 2 concentrations (0.5%–2%) to produce pretreated bamboo residues for enzymatic hydrolysis. Meanwhile, physicochemical features of the residual cellulose and lignin were analyzed to better understand how SEW improves enzymatic digestibility. Under optimized SEW pretreatment condition (1% SO 2 concentration, 150 °C, 60 min), 81.7% of xylan and 80.3% of lignin were solubilized, along with 89.1% of cellulose preserved in pretreated solid. A good enzymatic digestibility (80.4%) was achieved at optimum SEW condition. Several compelling correlations (R 2  > 0.7) were observable between enzymatic digestibility and physicochemical features, demonstrating the importance of SEW pretreatment abilities of hemicellulose and lignin removal, reducing cellulose’s degree of polymerization, and improving the amount of sulfonyl groups imparted to the original lignin structure. [ABSTRACT FROM AUTHOR]

This study assesses the potential for composted bamboo residues to serve as a renewable replacement for peat in horticultural growing media. Bamboo residues and wheat bran compost (ratio 90:10) were prepared in two batches, with (B1) and without (B2) effective microorganisms, and mixed with peat at 25%, 50%, 75%, and 100% by volume. Both batches were then used in greenhouse tests with two horticultural plants, Osmanthus fragrans (Thunb.) Lour. and Hydrangea macrophylla (Thunb.) Ser., using pure peat as a control. Batch B1 showed higher peak temperature and longer thermophilic phase than B2 during composting, and had higher N but lower total C and C/N ratio than B2. The addition of either batch to the growth media increased bulk density, particle density, and air space compared with pure peat, but decreased total pore space and total water-holding capacity. At lower compost content, the physical and chemical properties of the test batches were very similar to those of an ideal substrate, especially those mixed with B1. Plants grown in media mixed with B1 (25% or 50%) or B2 (25%) showed no significant differences in growth rates for height and ground diameter compared to those of the pure peat control. The results suggest that using effective microorganisms can increase mineralization during composting of bamboo residues, and that composted bamboo residues should be considered as a component of horticultural growth media in partial substitution for costly and less sustainable peat. [ABSTRACT FROM AUTHOR]

Synopsis: An innovative and efficient hydrogen peroxide-citric acid pretreatment was used to examine its effectiveness on bamboo residues. [Display omitted] • Citric acid and hydrogen peroxide prepared strong oxidizing peroxy-citric acid. • HPCA pretreatment effectively removed lignin (95.4%) and xylan (55.4%) in DG. • The enzymatic saccharification yield of HPCA-treated DG was more than 96%. • HPCA pretreatment was green and efficient in bamboo biorefinery. Organic peracids has attracted widespread attention from researchers in biomass pretreatment. As a weak acid with high production, low price and toxicity, citric acid (CA) was mixed with hydrogen peroxide at the room temperature to generate peroxy-citric acid with strong oxidative functions. An innovative and efficient pretreatment method using peroxy-citric acid (HPCA) was proposed to enhance enzymatic hydrolysis and bioethanol production of bamboo residues. After D. giganteus (DG) was pretreated with HPCA at 80 °C for 3 h, lignin of 95.36% and xylan of 55.41% was effectively removed, and the enzymatic saccharification yield of HPCA-treated DG enhanced by about 8–9 times compared with CA pretreated DG. The ethanol recovery of 17.18 g/L was achieved. This work provided a reference for mild biomass pretreatment, which will promote the large-scale application of organic peracids system in biorefinery processes. [ABSTRACT FROM AUTHOR]

A novel integrated process to coproduce bioethanol and lignosulfonate from bamboo residues was investigated. Explicitly, the fermentable sugars (glucose and xylose) were saccharified from the kraft pulped bamboo residues with 12 % effective alkaline charge, followed by a sequential fermentation strategy was applied to produce bio-ethanol from these fermentable sugars. The kraft lignin (KL) generated in pulping process and the enzymatic hydrolysis residues (EHR) were sulfomethylated to produce lignosulfonate. Results showed that 229.8 g of KL, 495.6 g of fermentable sugars (368.7 g glucose and 126.9 g xylose) and 103.6 g of EHR were generated from 1000 g bamboo residues after consequent processes of kraft pulping and enzymatic hydrolysis, respectively. Under optimal conditions of fermentation and sulfomethylation, 1000 g bamboo residues could produce 201.4 g of ethanol (158.7 g from glucose and 42.7 g from xylose) and 234.9 g of pure lignosulfonate (197.6 g from KL and 37.3 g from EHR) from 1000 g bamboo residues. This integrated process may potential be an economically profitable for the biorefinery of bamboo residues. [ABSTRACT FROM AUTHOR]

Nitrogen-enriched activated carbons prepared from bamboo residues were characterized by means of BET, XPS, and elemental analysis. Then adsorption experiments were carried out to study the effects of various physicochemical parameters such as contact time, temperature, pH, and initial concentration. Adsorption equilibrium was achieved within 120 min at a phenol concentration of 250 mg/L. When the pH was 4 and 0.1 g of the carbon absorbent and 100 mL of phenol solution at 250 mg/L were used, the phenol adsorption of the ACs with melamine and urea modifications were 219.09 mg/g and 214.45 mg/g, respectively. Both were greater than the capacity of unmodified AC, which was 163.82 mg/g. The Langmuir isotherm adsorption equation well described the experimental adsorption isotherms. The adsorption kinetics was well explained by pseudo-second-order kinetics rather than the pseudo-first-order. In conclusion, the nitrogen-enriched activated carbon proposed as adsorbents of the phenol wastewater were shown to be effective, which also means that bamboo residues have promise as activated carbon precursors for liquid phase adsorbents for environmental protection.

Alkali extraction was used to assist the Fenton pretreatment for overcoming the recalcitrance of bamboo and producing more sugar-based chemicals and bioethanol. The alkali-aided Fenton pretreatment showed the delignification of 55.33% and xylan removal of 80.76%. The surface lignin coverage, hydrophobicity, specific surface area, and cellulose crystallinity index were obviously changed by the combined pretreatment, which made cellulose accessibility increased by about 2-folds than Fenton pretreatment alone. The cleavage of β-O-4 linkage, the decrease of condensed structure and syringyl unit were observed in the residual lignin from the NaOH-Fenton pretreated D. brandisii , all of which reduced the nonproductive adsorption between enzymes and lignin. When NaOH-Fenton pretreated four bamboo residues were performed enzymatic hydrolysis, glucose yields of 66–74% and ethanol concentration of 11–16 g/L were obtained. The sequential NaOH-Fenton pretreatment should be considered as an environmentally-friendly bamboo biorefinery technology in the future. [Display omitted] ● NaOH-Fenton pretreatment removed 55.33% lignin and 80.76% xylan from bamboo. ● Glucose yield and ethanol content of NaOH-Fenton-DB was 76.13% and 15.44 g/L. ● Combined pretreatment reduced the nonproductive binding of lignin to enzyme. ● The combined pretreatment had exerted synergistic effects on enhancing enzymatic hydrolysis of bamboo. [ABSTRACT FROM AUTHOR]

Detailed kinetic triplets and thermodynamic studies of the three main components are important in the efficient design of the pyrolysis process. In this work, the three main components (cellulose, hemicellulose and lignin) of lignocellulosic biomass were extracted from bamboo residues (BR). The kinetic triplets and thermodynamic parameters of BR and its three components were then interpreted using thermogravimetric analysis. Three iso-conversional methods (Friedman, Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose models) estimated the average activation energy of BR and the extracted cellulose, hemicellulose and lignin to be 164.5, 145.3, 186.0 and 182.7 kJ mol−1, respectively. The frequency factors of BR ranged from 1013 to 1018 min−1 according to the Kissinger method, and the average frequency factors of the three main components were cellulose < hemicellulose < lignin. The master plots reveal the dominance of the diffusion mechanism in the pyrolysis process. The change in enthalpy (109.5–297.1 kJ mol−1) and Gibb free energy (138.7–156.3 kJ mol−1) indicated the endothermic and non-spontaneous nature of the pyrolysis of BR and the three main components. Kinetic and thermodynamic analyses confirmed the feasibility of BR as a potential candidate for bioenergy. [Display omitted] • The kinetics triplets of bamboo residues and its three extracted components were studied. • The activation energy of bamboo residues varies between 142.95 and 201.23 kJ mol−1. • The frequency factors of bamboo residues ranged from 1013 to 1018 min−1. • The dominance of the diffusion mechanism in the pyrolysis process was revealed. • Thermodynamic parameters of bamboo residues and its components were proposed. [ABSTRACT FROM AUTHOR]

The parenchymal cells in bamboo are an attractive source of raw materials due to their low degree of lignification and relatively loose cell wall structures. In this study, nanocellulose fibrils (NCFs) were isolated via a combined process of ultrasonication and chemical pretreatment of parenchymal cells separated from Moso bamboo (Phyllostachys pubescens) by means of a simple screening approach. As indicators of the fibrillation degree served the morphology, optical properties, and dynamic viscosity of the prepared NCF hydrogel as function of ultrasonication time. The mechanical properties of NCF derived films were also determined. The results show that high-quality NCFs can easily be prepared from bamboo parenchymal cells through the above-mentioned process, with an optimal ultrasonication time of 40 min. The utilization of bamboo processing residues via the ultrasonication route is promising and for energy saving production of high-quality NCFs at large scale. [ABSTRACT FROM AUTHOR]

During the biomass pretreatment, the formation and repolymerization of lignin droplets on the surface of cell wall has a negative impact on the cellulose accessibility and enzymatic saccharification. When D. sinicus (DS) was treated with tetraethylammonium chloride/Oxalic acid-based deep eutectic solvent (TEAC/OA) at 120 °C and 7 h, the sodium carbonate and sodium hydroxide washing of pretreated residues decreased the surface lignin content by about 27 % as compared to that cleaned with hot water, which can generate more cellulose accessible sites for enzymatic digestibility. Finally, the higher glucose yields of 70.69 % for sodium carbonate washing and 76.25 % for sodium hydroxide washing were achieved. This work provided an insight to overcome the negative effects of surface lignin and open a window for the efficient bamboo biorefinery of DES systems in southwest China. • A DES pretreatment of TEAC/OA was developed for the bamboo residues biorefinery. • Organic solvent washing can reduce the surface lignin content in pretreated bamboo. • Cellulose accessibility of DS-SC and DS-SH improved by about 1.5 times than DS-DW. • Glucose yield of 70.69 % for DS-SC and 76.25 % for DS-SH was achieved. [ABSTRACT FROM AUTHOR]

Cooking additive pulping technique is used in kraft mill to increase delignification degree and pulp yield. In this work, cooking additives were firstly applied in the sodium hydroxide pretreatment for improving the bioconversion of bamboo residues to monosaccharides. Meanwhile, steam explosion and sulfuric acid pretreatments were also carried out on the sample to compare their impacts on monosaccharides production. Results indicated that associating anthraquinone with sodium hydroxide pretreatment showed the best performance in improving the original carbohydrates recovery, delignification, enzymatic saccharification, and monosaccharides production. After consecutive pretreatment and enzymatic saccharification process, 347.49 g, 307.48 g, 142.93 g, and 87.15 g of monosaccharides were released from 1000 g dry bamboo residues pretreated by sodium hydroxide associating with anthraquinone, sodium hydroxide, steam explosion and sulfuric acid, respectively. The results suggested that associating cooking additive with sodium hydroxide is an effective pretreatment for bamboo residues to enhance enzymatic saccharification for monosaccharides production. [ABSTRACT FROM AUTHOR]

A alkaline deacetylation-aided hydrogen peroxide-acetic acid pretreatment pretreatment was applied to examine its effectiveness on bamboo biomass. [Display omitted] • Acetyl groups from HPAC pretreatment were removed by mild NaOH post-treatment. • Deacetylation increased the productive binding of pretreated bamboo to enzyme. • Glucose yield of HPAC-NaOH-DS was 91.30%, improved by 27% than HPAC-DS. • When five HPAC-NaOH-bamboo as substrates, glucose yield of 82-96% were achieved. • HPAC-NaOH pretreatment was efficient and economical in the bamboo biorefinery. 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. [ABSTRACT FROM AUTHOR]

Nitrogen-enriched activated carbons prepared from bamboo residues were characterized by means of BET, XPS, and elemental analysis. Then adsorption experiments were carried out to study the effects of various physicochemical parameters such as contact time, temperature, pH, and initial concentration. Adsorption equilibrium was achieved within 120 min at a phenol concentration of 250 mg/L. When the pH was 4 and 0.1 g of the carbon absorbent and 100 mL of phenol solution at 250 mg/L were used, the phenol adsorption of the ACs with melamine and urea modifications were 219.09 mg/g and 214.45 mg/g, respectively. Both were greater than the capacity of unmodified AC, which was 163.82 mg/g. The Langmuir isotherm adsorption equation well described the experimental adsorption isotherms. The adsorption kinetics was well explained by pseudo-second-order kinetics rather than the pseudo-firstorder. In conclusion, the nitrogen-enriched activated carbon proposed as adsorbents of the phenol wastewater were shown to be effective, which also means that bamboo residues have promise as activated carbon precursors for liquid phase adsorbents for environmental protection. [ABSTRACT FROM AUTHOR]

A three-constituent deep eutectic solvent (3c-DES) pretreatment with choline chloride-oxalic acid-ethylene glycol was applied to examine its effectiveness on bamboo residues. [Display omitted] A three-constituent deep eutectic solvent (3c-DES) pretreatment with choline chloride-oxalic acid-ethylene glycol was applied to examine its effectiveness on bamboo residues. The 3c-DES pretreatment can remove 91.09% xylan and significantly improved the 72 h hydrolysis yield of D. sinicus by 6.3 and 1.7 times as compared with the liquid hot water and two-constituent deep eutectic solvent (2c-DES) pretreatment. The introduction of ethylene glycol (EG) into choline chloride (ChCl)/ oxalic acid (OA) decreased the content of surface lignin and the condensation of lignin, which contributed to the increase of hydrophilic nature and cellulose accessibility in substrates. Moreover, higher glucose (85.72%) and xylose (91.05%) yields of 3c-DES pretreated bamboo were achieved with the addition of Tween 80. The 3c-DES system provides an alternative approach for the development of efficient bamboo pretreatment, and had broad space for bamboo biorefinery in southern China. [ABSTRACT FROM AUTHOR]

• 91.6% of lignin in BR could be removed by acid/phenoxyethanol pretreatment. • Enzymatic yield of 91.3% was achieved for BR pretreated by phenoxyethanol. • Enzymatic yield linearly correlated (R2 > 0.7) to physicochemical property of BR. • Recycle preteatment liquor and using low enzyme still showed good enzymatic yield. The high content of lignin in bamboo is considered as the major obstacle for its biorefining. In this work, a green, lignin-selective, and recyclable solvent of phenoxyethanol was coupled with acid solution to deconstruct recalcitrant structure of bamboo residues (BR) to boost its enzymatic digestibility. Results showed phenoxyethanol has excellent lignin-removal ability from 29.4% to 91.6% when phenoxyethanol:acid ratios increased from 0:1 to 4:1 at 120 °C. 82.5%–87.8% of cellulose was preserved in pretreated BR. The enzymatic digestibility of BR significantly improved from 20.0% to 91.3% when it was pretreated under optimized conditions. With lower enzyme dosages (10 FPU/g) and 5 recycled using of pretreatment liquor, pretreated BR still showed a good enzymatic digestibility of 67.4%–93.7% and 67.1–76.8%, respectively. Examination of physicochemical changes revealed that improvements to accessibility, reduction of crystallite size, decrease of surface lignin and hydrophobicity for pretreated BR showed positive correlations (R2 > 0.7) with their enzymatic digestibility. [ABSTRACT FROM AUTHOR]

• The volume utilization rate of bamboo residues is more than 85%. • The O 2 plasma modification time is 6min, the wet bonding strength is increased by 75.69%. • The staggered arrangement of bamboo pieces in LBL can reduce the influence of anisotropy. • After O 2 plasma modification, the wettability of bamboo was improved obviously. To improve the reuse rate of bamboo materials, laminated bamboo lumber (LBL) with high bond strength has been developed for structural use using bamboo residues (BRs). The laminated structure design is an important factor affecting LBL performance, and thus, it is essential to study various LBL blank structures. The major direction is parallel to the panel length, and the minor direction is perpendicular to the panel length. In this study, BRs were cut into A and B units along the major and minor directions, respectively. The LBL with good performance was selected by different forming methods and modified by O 2 plasma. It was found that 1) the volume utilization rate of BRs in LBL is above 85%; 2) the wet bonding strength of LBL products is increased by 58.58% compared to ordinary plywood, when the O 2 plasma modification time is 6 min and 12 min respectively, the wet bonding strength is increased by 75.69% and 76.27% compared to ordinary plywood; 3) when bamboo pieces are arranged in parallel, the modulus of rupture in the major direction is ~ 2 times greater than in the minor direction, while a staggered arrangement can effectively reduce the bamboo anisotropic effect; 4) the destruction of LBL mainly occurs at the joints; 5) after O 2 plasma modification, the wettability of green bamboo and yellow bamboo was significantly improved, followed by bamboo flesh. [ABSTRACT FROM AUTHOR]

In this study, bamboo residues derived functional hydrochar microspheres have been fabricated by different acids-assisted hydrothermal carbonization including hydrochloric aicd, sulfuric acid or nitric acid.The energy-dispersive X-ray fluorescence spectroscopy and Fourier Transform Infrared spectroscopy analyses showed that sulfur- and nitrogen-containing functional groups were grafted on the surface of hydrochar microspheres, respectively. Elemental analysis indicates that the addition of acids has a significant influence on the hydrothermal reaction pathway and promotes the hydrolysis process. When the hydrothermal carbonization temperature is 220 °C, hydrochloric acid and nitric acid can effectively overcome the agglomeration of hydrochar microspheres and form single micron carbon sphere. Irregularly shaped hydrochar particles groups were formed during sulfuric acid-assisted hydrothermal treatment. The results indicate the viability of acid assisted hydrothermal carbonization to produce the functional hydrochar microsphere using bamboo residues. • Acids changed hydrothermal reaction pathway and accelerated hydrolysis process. • HCl and HNO 3 aided hydrothermal treatment overcome hydrochar spheres agglomeration. • Sulfuric and nitrogen groups were grafted on the surface of hydrochar microspheres. [ABSTRACT FROM AUTHOR]

• 50% bamboo residues (BR) with textile dyeing sludge (TDS) had the greatest synergy. • Adding BR increased CO 2 , CO, CH 4 , C O and C O emissions from co-pyrolysis. • Adding 50% BR significantly reduced NH 3 and HCN emissions from co-pyrolysis. • Co-pyrolysis enhanced the formations of more N-5 and N-Q structures in biochar. • Co-pyrolysis inhibited the hydrogenation and ring-opening reactions at N-sites. This study aimed to investigate the synergistic influences of the textile dyeing sludge (TDS) and bamboo residues (BR) co-pyrolysis, and its effects on the formation mechanisms of NH 3 and HCN. The mass loss rate was lower for TDS than BR, with the co-pyrolysis with 50% BR exerting the strongest synergistic effect. The pyrolysis stages 1 (< 400 °C) and 2 (400−800 °C) were best described using the diffusion and third-order reaction mechanisms, respectively. Activation energy and frequency factor were lower for the pyrolysis of TDS than BR. The addition of no less than 50% BR significantly increased the emissions of CO 2 , CO, CH 4 , C O, and C O and reduced the aromatic compounds. The thermal stability of N-A structure was lower in TDS than BR. The co-pyrolysis with 50% BR significantly inhibited the formations of NH 3 and HCN and improved the aromaticity of biochar. This may due to the weakened hydrogenation reaction at N sites, the enhanced conversion of NH 3 , the inhibition of the ring cleavage in the char-secondary cracking, and the formation of more quaternary-N. Our results provide insights into the co-treatment of TDS and BR, and controls over NO x precursors for a cleaner energy production. [ABSTRACT FROM AUTHOR]

The catalytic combustions of bamboo leaves (BL) and branches (BB) with textile dyeing sludge ash (SA), Fe 2 O 3 , and CaO were qualitatively analyzed using thermogravimetric and Fourier transform infrared spectroscopy analyses, and thermodynamic equilibrium simulations. The catalysts (Fe 2 O 3 > SA > CaO) exerted a more pronounced effect in the char combustion (third) stage and enhanced the volatiles and comprehensive combustion indices with 40 °C/min. The catalysts (CaO > SA > Fe 2 O 3) reduced C- and N-containing gas emissions in the devolatilization (second) stage. CaO elevated the N-containing gas emission in the third stage, whereas Fe 2 O 3 and SA inhibited the formation of NO precursors. BB presented a higher risk of slagging than did BL, while the improved empirical indices of the ash deposition pointed to CaO as the optimal catalyst. Our simulations showed the final ash components of BL and BB were mainly as SiO 2 and K 2 Si 4 O 9. The addition of CaO alone helped to form a high-melting point Ca-silicate. Although the addition of Fe 2 O 3 had no effect on the ash conversion, SA reduced the formation of K-silicate in the ash. The catalysts (CaO > SA > Fe 2 O 3) reduced the activation energy. Overall, the catalytic combustions improved the bioenergy and the N-containing gas emissions. SA as a Fe and Ca-rich industrial waste enhanced the combustion performance in terms of reductions in waste streams, gas emissions, and ash deposition. Our results supplied new insights into the efficient and clean bioenergy production of bamboo residues, and the waste utilization of SA. Image 1 • Two bamboo residues were combusted using sludge ash (SA), CaO and Fe 2 O 3 catalysts. • Catalysts increased volatiles and combustion performances with a high heating rate. • Catalytic emission reductions in NH 3 and NO were CaO > SA > Fe 2 O 3. • The conversion of K–SiO 2 was affected by CaO and SA but not by Fe 2 O 3. • CaO reduced the activation energy the most. [ABSTRACT FROM AUTHOR]

• Itaconic acid was produced using bamboo residues as substrates. • Itaconic acid was produced from lignocellulose without detoxification. • High itaconic acid titer was obtained by fermentation strategies. Itaconic acid (IA) production by fermentation of undetoxified hydrolysate of bamboo residues by Aspergillus terreus was demonstrated. Monosaccharides were obtained by pretreatment and enzymatic hydrolysis of bamboo residues. A. terreus could not grow and synthesize IA in the hydrolysate. The buffer was confirmed to be an inhibitor, and was successfully replaced by deionized water as the suspension, to release equivalent sugar and eliminate the inhibition. Corn steep liquor significantly improved the adaptability of A. terreus to the hydrolysate at 2.0 g/L. The IA titer obtained (19.35 g/L IA) was the highest to be reported for IA production from lignocellulose without detoxification. Simultaneous saccharification and fermentation and fed-batch fermentation increased the titer to 22.43 g/L and 41.54 g/L, respectively. Meanwhile, economic assessment proved that bamboo residues were potential substrates for IA production with economic effectiveness. [ABSTRACT FROM AUTHOR]

• Enzymatic digestibility of 76.9% was achieved for DES-pretreated bamboo residues. • Changes of cellulose properties made contribute to the enzymatic digestibility. • Enzymatic digestibility linearly correlated to change of physicochemical property. Deep eutectic solvent (DES) is a promising pretreatment for improving enzymatic digestibility of lignocellulosic material by altering the physicochemical properties. However, few work has been done to quantitatively analysis the physicochemical properties changes of lignocellulosic material with enzymatic digestibility. In this work, DES pretreatment with different molar ratios of choline chloride/lactic acid was carried out on bamboo residues and respective enzymatic digestibility was investigated and linearly fitted with corresponding physicochemical features changes of the pretreated bamboo residues. Results showed that enzymatic digestibility of DES-pretreated bamboo residues was enhanced with the increasing molar ratio of choline chloride/lactic acid, which was due to DES pretreatment's ability to remove lignin and xylan, reduce the degree of polymerization of cellulose, enhance the crystallite size of cellulose, and improve cellulose accessibility. Several compelling linear correlations (R2 = 0.6–0.9) were observable between enzymatic digestibility and these changes of physicochemical properties, demonstrating how DES pretreatment improve the enzymatic digestibility. [ABSTRACT FROM AUTHOR]

• Properties of bamboo residues (BR) torrefied between 250 and 300 °C were improved. • The main deoxidation products of torrefaction were CO 2 and carbonyl compounds. • Torrefied BR combustions increased CO 2 decreased NH 3 and NO emissions. • Torrefaction delayed the start and end times of BR combustion. • Torrefaction changed the BR combustion mechanism from nucleation to diffusion. Unlike light torrefaction at 200 °C (B200), the mild (250 °C) and severe (300 °C) torrefaction pretreatments (B250 and B300) significantly increased the calorific value, reduced the oxygen content and improved the surface morphology for bamboo residues (BR). The main oxygen-removing carriers of BR during torrefaction were CO 2 and carbonyl compounds. Their torrefaction delayed the start and burnout temperatures of the BR combustions, increased CO 2 emission and decreased NH 3 and NO emissions significantly. The torrefaction reduced their activation energy in zone II (200–350 °C) and led to a transition from a nucleation to a diffusion mechanism. All the combustions in zone III (350–500 °C) were best explained by a reaction order model whose order rose with the elevated torrefaction temperature. Overall, BR appeared to be more suitable for the torrefaction at 250–300 °C. Our results can provide practical insights into how to turn BR into efficient and clean bioenergy. [ABSTRACT FROM AUTHOR]

• Post-extraction removed the lignin and disrupted inhibitory properties. • Urea-extraction can remove 30% of lignin for enhancing the enzymatic hydrolysis. • Post-extraction improved enzymatic digestibility of acid-pretreated bamboo. • Physicochemical features showed correlations with enzymatic digestibility. In this work, a mild and facile post-extraction using different reagents was evaluated to overcome these recalcitrance for improving the enzymatic digestibility of acid-pretreated bamboo residues by removing the lignin and disrupting its inhibitory properties. Results showed that the enzymatic digestibility of acid-pretreated bamboo residues can be improved from 15.4% to 61.4%, 59.7%, and 42.8% by room temperature post-extraction with phosphoric acid, urea, and ethanol, respectively. Several compelling correlations (R2 > 0.5) were observable between enzymatic digestibility and structural changes, including delignification, reducing of substrate hydrophobicity, altering cellulose crystallinity, and elevations to the residual lignin syringyl-to-guaiacyl (S/G) ratio and functional groups. The results serve as a demonstration of the downstream value that can be gained when coupling a post-extraction process with acid pretreatment of bamboo residues, resulting in greater fermentable sugar production. [ABSTRACT FROM AUTHOR]