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This study evaluated the use of a renewable organic acid (citric acid) as homogeneous catalyst for the pretreatment of raw sugarcane bagasse (SB). A 22 central composite design with two factors (reaction time and citric acid concentration) was used to evaluate the effect of the factors on the chemical composition of the pretreated SB samples and enzymatic hydrolysis efficiency. The enzymatic hydrolysis experiments of the pretreated SB samples were performed using the enzymatic cocktail Cellic® CTec 3 and the total reducing sugars (TRS) released after enzymatic hydrolysis was determined. In addition, scanning electron microscopy and X-ray diffraction were used to examine the changes in the morphology and structure of the pretreated SB samples. The changes in the structure and chemical composition of the pretreated SB resulted in a high TRS concentration (28.2 g L−1) after enzymatic hydrolysis, for the pretreatment condition employing 6 wt% citric acid and 102.4 min, compared to the raw SB (3.06 g L−1). The pretreatment showed potential for application since a moderate conversion of polysaccharides in TRS was obtained, even though it was a pretreatment carried out under milder conditions. The pretreatment studied has the advantage of using weak and environmentally friendly acid catalyst, atmospheric pressure, and low temperature. • Pretreatment of sugarcane bagasse (SB) with citric acid was studied. • Chemical, structural and morphological changes of SB was investigated. • Changes in the SB was effective in improve sugar conversion by enzymatic hydrolysis. • High concentrations of total reducing sugars (28.2 g L−1) in comparison to the raw SB (3.06 g L−1) was obtained. [ABSTRACT FROM AUTHOR]

Organosolv delignification assisted by high–pressure carbon dioxide (HP–CO 2 ), a low cost, non–corrosive and recoverable compound was evaluated as a potential green pretreatment technology for lignin extraction from liquid hot water (LHW) pretreated sugarcane bagasse to produce fermentable sugars in a lignocellulosic biorefinery concept. In this study, LHW pretreated bagasse (180 °C for 20 min with a liquid–to–solid ratio ( LSR ) of 9 (v/w)) was delignified with an ethanol–water mixture (1:1, v/v) and HP–CO 2 as a co–solvent at milder temperatures (111.7–168.3 °C) and times (23.8–66.2 min) at a LSR of 5 (v/w). To evaluate the effects of varying operational conditions on the lignin content and delignification extent, while preserving the glucan fraction, a 2 2 central composite design was used as a factorial planning. Solid fractions with low lignin contents (7.35% and 10.78%) and high delignification extents (82.5% and 72.2%) with good glucan preservations (84.6% and 85.3%) were obtained at 140 °C for 45 min and 111.7 °C for 45 min, respectively. These solid fractions were subjected to enzymatic hydrolysis, yielding enzymatic conversions of 60.8% and 63.7%, respectively. [ABSTRACT FROM AUTHOR]

Highlights: [•] LHW-HP-CO2 evaluated as a potential green technology for hemicelluloses extraction. [•] At 100°C for 30min and 115°C for 60min xylan equivalent ranged 10–12g/L. [•] At 115°C for 60min, the cellulose preservation achieved 97.2%. [•] Enzymatic hydrolysis yielded 30.43g/L glucose and 41.17% cellulose conversion. [ABSTRACT FROM AUTHOR]

In this study sugarcane bagasse was modified with succinic anhydride and EDTA dianhydride to obtain SCB 2 and EB adsorbents, respectively. These adsorbents were used to remove etherdiamine, which is used for iron ore flotation from single aqueous solutions. The removal and recovery of etherdiamine is important for environmental and economic reasons due to its toxicity and high cost. The results demonstrated that adsorption of etherdiamine by SCB 2 and EB was better fitted by a pseudo-second-order kinetic model than pseudo-first-order and Elovich models. Adsorption isotherms were better fitted by the Langmuir model rather than the Freundlich, Sips, and Temkin models. The maximum adsorption capacities (Q max) of SCB 2 and EB for etherdiamine adsorption were found to be 869.6 and 1203.5 mg/g, respectively. The calculated ΔG° values for adsorption of etherdiamine on SCB 2 (−22.70 kJ/mol) and EB (−19.10 kJ/mol) suggested that chemisorption is the main mechanism by which etherdiamine is removed from the aqueous solution for both adsorbents. The high Q max values showed that SCB 2 and EB are potential adsorbents for recovering the etherdiamine and treating effluents produced from iron ore flotation. [Copyright &y& Elsevier]

Abstract: In this study the adsorption of cationic dyes by modified sugarcane bagasse with EDTA dianhydride (EB) was examined using methylene blue (MB) and gentian violet (GV) as model compounds in aqueous single solutions. The synthesized adsorbent (EB) was characterized by FTIR, elemental analysis, and BET. The capacity of EB to adsorb dyes was evaluated at different contact times, pH values, and initial dye concentrations. According to the obtained results, the adsorption processes could be described by a pseudo-second-order kinetic model. The adsorption isotherms were well fitted by the Langmuir model. Maximum adsorption capacities for MB and GV on EB were found to be 202.43 and 327.83 mg/g, respectively. The free energy change during adsorption of MB and GV was found to be −22.50 and −24.21 kJ/mol, respectively, suggesting that chemisorption is the main mechanism controlling the adsorption process. [Copyright &y& Elsevier]

Abstract: Sugarcane bagasse cellulose was subjected to the extremely low acid (ELA) hydrolysis in 0.07% H2SO4 at 190, 210 and 225°C for various times. The cellulose residues from this process were characterized by TGA, XRD, GPC, FTIR and SEM. A kinetic study of thermal decomposition of the residues was also carried out, using the ASTM and Kissinger methods. The thermal studies revealed that residues of cellulose hydrolyzed at 190, 210 and 225°C for 80, 40 and 8min have initial decomposition temperature and activation energy for the main decomposition step similar to those of Avicel PH-101. XRD studies confirmed this finding by showing that these cellulose residues are similar to Avicel in crystallinity index and crystallite size in relation to the 110 and 200 planes. FTIR spectra revealed no significant changes in the cellulose chemical structure and analysis of SEM micrographs demonstrated that the particle size of the cellulose residues hydrolyzed at 190 and 210°C were similar to that of Avicel. [Copyright &y& Elsevier]

Abstract: This paper describes the organosolv delignification of depithed bagasse using glycerol–water mixtures without a catalyst. The experiments were performed using two separate experimental designs. In the first experiment, two temperatures (150 and 190°C), two time periods (60 and 240min) and two glycerol contents (20% and 80%, v/v) were used. In the second experiment, which was a central composite design, the glycerol content was maintained at 80%, and a range of temperatures (141.7–198.3°C) and time (23–277min) was used. The best result, obtained with a glycerol content of 80%, a reaction time of 150min and a temperature of 198.3°C, produced pulps with 54.4% pulp yield, 7.75% residual lignin, 81.4% delignification and 13.7% polyose content. The results showed that high contents of glycerol tend to produce pulps with higher delignification and higher polyoses content in relation to the pulps obtained from low glycerol content reactions. In addition, the proposed method shows potential as a pretreatment for cellulose saccharification. [Copyright &y& Elsevier]

Abstract: In a previous work, chemically modified cellulose (EMC) and sugarcane bagasse (EMMB) were prepared from mercerized cellulose (MC) and twice-mercerized sugarcane bagasse (MMB) using ethylenediaminetetraacetic dianhydride (EDTAD) as modifying agent. In this work we described in detail the modification of these materials in function of reaction time and EDTAD amount in the reaction media. The resistance of ester bond at pH 1, 2, 11, and 12 was also evaluated by FTIR. The results were used to model the hydrolysis process and a kinetic model was proposed. The modified materials (EMMB and EMC) were used to adsorb Ca2+ and Mg2+ ions from aqueous single solutions. The adsorption isotherms were developed at two pH values. These materials showed maximum adsorption capacities for Ca2+ and Mg2+ ions ranging from 15.6 to 54.1mg/g and 13.5 to 42.6mg/g, respectively. The modified material from sugarcane bagasse (EMMB) showed larger maximum adsorption capacities than modified material from cellulose (EMC) for both metals. [Copyright &y& Elsevier]

Abstract: This study describes the preparation of two new chelating materials, MMSCB 3 and 5, derived from succinylated twice-mercerized sugarcane bagasse (MMSCB 1). MMSCB 3 and 5 were synthesized from MMSCB 1 using two different methods as described by . In the first method MMSCB 1 was activated with 1,3-diisopropylcarbodiimide and in the second with acetic anhydride (to form an internal anhydride) and later both were reacted with triethylenetetramine in order to obtain MMSCB 3 and 5. New obtained materials were characterized by mass percent gain, concentration of amine groups, FTIR, and elemental analysis. MMSCB 3 and 5 showed mass percent gain of 19.9 and 57.1%, concentration of amine groups of 2.0 and 2.1mmol/g, and nitrogen content of 5.8 and 4.4%. The capacity of MMSCB 3 and 5 to adsorb Cu2+, Cd2+, and Pb2+ from aqueous single metal ion solutions was evaluated at different contact times, pHs, and initial metal ion concentrations. Adsorption isotherms were well fitted by Langmuir model. Maximum adsorption capacities of MMSCB 3 and 5 for Cu2+, Cd2+, and Pb2+ were found to be 59.5 and 69.4, 86.2 and 106.4, 158.7 and 222.2mg/g, respectively. [Copyright &y& Elsevier]

Abstract: This work describes the preparation of new chelating materials derived from cellulose and sugarcane bagasse for adsorption of Cu2+, Cd2+, and Pb2+ ions from aqueous solutions. The first part involved the mercerization treatment of cellulose and sugarcane bagasse with NaOH 5mol/L. Non- and mercerized cellulose and sugarcane bagasse were then reacted with ethylenediaminetetraacetic dianhydride (EDTAD) in order to prepare different chelating materials. These materials were characterized by mass percent gain, X-ray diffraction, FTIR, and elemental analysis. The second part consisted of evaluating the adsorption capacity of these modified materials for Cu2+, Cd2+, and Pb2+ ions from aqueous single metal solutions, whose concentration was determined by atomic absorption spectroscopy. These materials showed maximum adsorption capacities for Cu2+, Cd2+, and Pb2+ ions ranging from 38.8 to 92.6mg/g, 87.7 to 149.0mg/g, and 192.0 to 333.0mg/g, respectively. The modified mercerized materials showed larger maximum adsorption capacities than modified non-mercerized materials. [Copyright &y& Elsevier]

Abstract: This work describes the preparation of new chelating material from mercerized sugarcane bagasse. The first part treats the chemical modification of non-mercerized sugarcane bagasse (SCB) and twice-mercerized sugarcane bagasse (MMSCB) with succinic anhydride. Mass percent gains (mpg) and degrees of succinylation (DS) of succinylated non- and twice-mercerized sugarcane bagasse 1 (SCB 1 and MMSCB 1) were calculated. MMSCB 1 exhibited an increase in mpg and DS of 49.2% and 0.9mmol/g in relation to SCB 1. SCB 2 and MMSCB 2 were obtained by treatment of MMSCB 1 and SCB 1 with bicarbonate solution to release the carboxylate functions and characterized by FTIR. The second part evaluates and compares the adsorption capacity of SCB 2 and MMSCB 2 for Cu2+, Cd2+ and Pb2+ ions in an aqueous single metal solution. Adsorption isotherms were developed using Langmuir model. MMSCB 2 exhibited an increase in Q max for Cd2+ (43.6mg/g) and Pb2+ (83.3mg/g) in relation to SCB 2. [Copyright &y& Elsevier]

In the context of a sugarcane biorefinery, sugarcane bagasse produced may be pretreated generating a solid and liquid fraction. The solid fraction may be used for 2G bioethanol production, while the liquid fraction may be used to produce biogas through anaerobic digestion. The aim of this study consisted in evaluating the anaerobic digestion performance of hemicellulose hydrolysate produced after hydrothermal pretreatment of sugarcane bagasse. For this, hydrothermal pretreatment was assessed in a continuous upflow anaerobic sludge blanket (UASB) reactor operated at a hydraulic retention time (HRT) of 18.4 h. Process performance was investigated by varying the dilution of sugarcane bagasse hydrolysate with a solution containing xylose and the inlet organic loading rate (OLR). Experimental data showed that an increase in the proportion of hydrolysate in the feed resulted in better process performance for steps using 50% and 100% of real substrate. The best performance condition was achieved when increasing the organic loading rate (OLR) from 1.2 to 2.4 g COD/L·d, with an organic matter removal of 85.7%. During this period, the methane yield estimated by the COD removal would be 270 L CH 4 /kg COD. Nonetheless, when further increasing the OLR to 4.8 g COD/L·d, the COD removal decreased to 74%, together with an increase in effluent concentrations of VFA (0.80 g COD/L) and furans (115.3 mg/L), which might have inhibited the process performance. On the whole, the results showed that anaerobic digestion of sugarcane bagasse hydrolysate was feasible and may improve the net energy generation in a bioethanol plant, while enabling utilization of the surplus sugarcane bagasse in a sustainable manner. [ABSTRACT FROM AUTHOR]

This study evaluated the pretreatment of sugarcane bagasse (SCB) with dilute citric acid solution for biogas production. The black liquor (BL) from pretreatment and residual solid fraction (RSF) obtained after enzymatic hydrolysis were used as substrates for the biogas production. After saccharifications of the pretreated solid fractions performed with Cellic® CTec 3 cocktail, the highest concentration of total reducing sugars (TRS) was in the range of 10.7–184.8 g L−1 and the sugar yields were in the range of 3.5–88.8%. For BL, the contents of glucose, xylose, and arabinose were in the range of 1.9–8.9 g L−1, 4.0–24.7 g L−1, and 0.2–5.4 g L−1, respectively. Biogas production from BL and RSF resulted, respectively, in maximum values of 563.6 and 57.8 NmL g COD −1, indicating the feasibility of using dilute citric acid pretreatment coupled to biogas production in biorefineries. Brief energy and economic assessment were carried out considering the energy balance (thermal energy generated by burning biogas - thermal energy spent in the pretreatment), as well as revenue from a possible sale of electricity generated in a combined heat and power system. [Display omitted] [ABSTRACT FROM AUTHOR]

Highlights: [•] Novel application for adsorbents after treating solutions containing metal ions. [•] New biobased heterogeneous catalysts were prepared for monoterpenes oxidation. [•] Production of high economic value oxygenated derivatives from monoterpenes. [•] Conversions among 49 and 78% and combined selectivity up to 59% were obtained. [Copyright &y& Elsevier]

Graphical abstract Abstract Sugarcane bagasse cellulose mixed ester succinate phthalate (SBSPh) was synthesized by a novel one-pot reaction method. The effects of temperature, time and mole fraction of succinic anhydride (χ SA) on the responses weight gain (wg), number of carboxylic acid groups (n T,COOH), and adsorption capacity (q) of Co2+ and Ni2+ were evaluated by a 23 experimental design. The chemical structure of the material was elucidated by Fourier transform infrared, 13C Multiple Cross-Polarization solid-state NMR spectroscopy and 1H NMR relaxometry. The best SBSPh synthesis condition (100 °C, 11 h, χ SA of 0.2) yielded a wg of 59.1%, n T,COOH of 3.41 mmol g−1, and values of q Co 2+ and q Ni 2+ of 0.348 and 0.346 mmol g−1, respectively. The Sips model fitted better the equilibrium data, and the maximum adsorption capacities (pH 5.75 and 25 °C) estimated by this model were 0.62 and 0.53 mmol g−1 for Co2+ and Ni2+, respectively. The Δ ads H ° values estimated by isothermal titration calorimetry were 8.43 and 7.79 kJ mol−1 for Co2+ and Ni2+, respectively. Desorption and re-adsorption efficiencies were evaluated by a 22 experimental design, which showed that SBSPh adsorbent can be recovered and reused without significant loss of adsorption capacity. [ABSTRACT FROM AUTHOR]

Trimellitated-sugarcane bagasse (STA) was used as an environmentally friendly adsorbent for removal of the basic dyes auramine-O (AO) and safranin-T (ST) from aqueous solutions at pH 4.5 and 7.0. Dye adsorption was evaluated as a function of STA dosage, agitation speed, solution pH, contact time, and initial dye concentration. Pseudo-first- and pseudo-second-order, Elovich, intraparticle diffusion, and Boyd models were used to model adsorption kinetics. Langmuir, Dubinin-Radushkevich, Redlich-Peterson, Sips, Hill-de Boer, and Fowler-Guggenheim models were used to model adsorption isotherms, while a Scatchard plot was used to evaluate the existence of different adsorption sites. Maximum adsorption capacities for removal of AO and ST were 1.005 and 0.638 mmol g −1 at pH 4.5, and 1.734 and 1.230 mmol g −1 at pH 7.0, respectively. Adsorption enthalpy changes obtained by isothermal titration calorimetry (ITC) ranged from −21.07 ± 0.25 to −7.19 ± 0.05 kJ mol −1 , indicating that both dyes interacted with STA by physisorption. Dye desorption efficiencies ranged from 41 to 51%, and re-adsorption efficiencies ranged from 66 to 87%, showing that STA can be reused in new adsorption cycles. ITC data combined with isotherm studies allowed clarification of adsorption interactions. [ABSTRACT FROM AUTHOR]

In the present study, the ozonation of sugarcane bagasse (SB) at different operational conditions (pH, time, liquid-to-solid ratio ( LSR )) was evaluated with the aim of generating a soluble liquid fraction (SLF) suitable for biogas production (CH 4 and H 2 ) via anaerobic digestion and a solid fraction prone to enzymatic hydrolysis and 2G ethanol production. The SLFs obtained were characterized for sugars, total organic carbon (TOC), soluble lignin, furans and other components identified by GC/MS. The results showed that it was possible to solubilize 45.2% of lignin, 48.3% of hemicelluloses and 40.7% of cellulose with the use of ozone (8 mg min −1 ) at pH 11 for 15 min, employing a LSR of 13.3 mL g −1 . The best results of biochemical methane potential (BMP) and biochemical hydrogen potential (BHP) were 2.6 Nm 3 of CH 4 and 0.18 Nm 3 of H 2 per kg of TOC, respectively. An energy balance for the best pretreatment conditions indicates that the combustion of such biogas led to an energy surplus of 0.1 MJ kg −1 SB for methane and to an energy deficit of 0.191 MJ kg −1 SB for hydrogen. Potentially inhibitory compounds for anaerobic digestion such as oxalic acid, butanal, xylitol, furanone, benzaldehyde, d -erythrotetrofuranose, d -erythro-pentofuranose and 2,5-furandione were identified in the hydrolysates, which negatively affected the anaerobic digestion and the energy balance. Nevertheless, the energy generated from the hydrolysates (as biogas) and from the ozonized solid fraction (as 2G ethanol) offsets the ozonation energy input and led to positive energy balance. [ABSTRACT FROM AUTHOR]

Bioethanol production from lignocellulose biomass offers a solution to current environmental challenges caused by fossil fuel energy resources, while satisfying the biorefinery concept. In this study, two-stage fractionation (autohydrolysis (AH) followed by glycerol organosolv delignification (GOD)) of sugarcane bagasse (SCB) was studied as a function of temperature, time, glycerol content and liquid-to-solid ( LSR ) ratio using experimental designs. The effect of three different AH pretreatment severities on delignification extents ( DE ) of the solid fractions were also evaluated. Scanning electron microscopy was used to examine the changes in the surface of SCB pretreated by AH. Energy balances of four fractionation conditions were estimated, and the use of pure and crude glycerol in GOD was evaluated based on DE and lignin contents. A DE of ∼64% was obtained at 210.3 °C, 40 min, LSR of 6.5 (v/w) and 80% (v/v) pure glycerol for GOD of SCB pretreated by AH at 175.8 °C, 49 min and LSR of 5.3 (v/w), which resulted in an energetic profitability ( EP ) of 141.48 MJ/kg SCB . The use of crude glycerol at 80% (v/v) under the same process conditions optimized for pure glycerol also proved to be feasible ( DE of ∼64% and EP of 142.67 MJ/kg SCB ), widening the possibilities for its direct use in GOD of SCB pretreated by AH in a 2G bioethanol integrated plant. [ABSTRACT FROM AUTHOR]

This study aimed at optimizing the net energy recovery from hydrogen and methane production through anaerobic digestion of the hemicellulose hydrolysate (HH) obtained by desirable conditions (DC) of autohydrolysis pretreatment (AH) of sugarcane bagasse (SB). Anaerobic digestion was carried out in a two-stage (acidogenic-methanogenic) batch system where the acidogenic phase worked as a hydrolysis and biodetoxification step. This allowed the utilization of more severe AH pretreatment conditions, i.e. T = 178.6 °C and t = 55 min (DC3) and T = 182.9 °C and t = 40.71 min (DC4). Such severe conditions resulted in higher extraction of hemicelluloses from SB (DC1 = 68.07%, DC2 = 48.99%, DC3 = 77.40% and DC4 = 73.90%), which consequently improved the net energy balance of the proposed process. The estimated energy from the combustion of both biogases (H 2 and CH 4 ) accumulated during the two-stage anaerobic digestion of HH generated by DC4 condition was capable of producing a net energy of 3.15 MJ·kg SB −1 dry weight . [ABSTRACT FROM AUTHOR]

This study aimed to optimize through design of experiments, the process variables (temperature – T , time – t and solid-to-liquid ratio – SLR ) for sugarcane bagasse (SB) autohydrolysis (AH) to obtain hemicellulose hydrolyzates (HH) prone to anaerobic digestion (AD) and biochemical methane production (BMP). The results indicated that severe AH conditions, which lead to maximum hemicelluloses dissolution and sugar content in the HH, were not the best for BMP, probably due to the accumulation of toxic/recalcitrant compounds (furans and lignin). Mild AH conditions (170 °C, 35 min and SLR = 0.33) led to the highest BMP (0.79 Nm 3 kg TOC −1 ), which was confirmed by the desirability tool. HH produced by AH carried out at the desired condition DC2 (178.6 °C, 43.6 min and SLR = 0.24) showed the lowest accumulation of inhibitory compounds and volatile fatty acids (VFA) and highest BMP (1.56 Nm 3 kg TOC −1 ). The modified Gompertz model best fit the experimental data and led to a maximum methane production rate ( R ) of 2.6 mmol CH 4 d −1 in the best condition. [ABSTRACT FROM AUTHOR]

This study describes, in detail, the chemical modification of sugarcane bagasse with phthalic anhydride to produce a carboxylate-functionalized sugarcane bagasse (SPA). The optimized modification conditions yielded SPA with a percent weight gain of 77.08% and an amount of carboxylic acid groups of 4.76 mmol/g. The SPA was characterized by PZC, FTIR, elemental analysis, TGA, and SEM-EDX. An SPA adsorbent was used to remove Co 2+ , Cu 2+ , and Ni 2+ from aqueous solution in mono- and multicomponent systems in batch mode. The adsorption kinetics followed a pseudo-second-order model. The adsorption rate constants assumed the following order: k 2,Co 2+ > k 2,Ni 2+ > k 2,Cu 2+ . Four mono- and multicomponent isotherm models were used to model the adsorption data. Monocomponent data were well described by the Langmuir model, whereas bicomponent data were well described by the modified extended Langmuir and P -Factor models. The maximum adsorption capacities ( Q max,mono ) for the Langmuir model were 0.561, 0.935, and 0.932 mmol/g for Co 2+ , Cu 2+ , and Ni 2+ , respectively. Adsorption in bicomponent systems revealed that Cu 2+ suppressed the adsorption of Co 2+ and Ni 2+ , whereas Ni 2+ suppressed the adsorption of Co 2+ . Desorption studies revealed that the SPA adsorbent could be fully desorbed with a 1 mol/L HNO 3 solution. [ABSTRACT FROM AUTHOR]

A new carboxylate-functionalized sugarcane bagasse (SMA) was prepared via a solvent-free procedure involving esterification of sugarcane bagasse with Meldrum's acid. The optimized conditions provided SMA with a percent weight gain of 86.0% and 4.69 ± 0.20 mmol/g of carboxylic acid groups. SMA was characterized by FTIR, TGA, elemental analysis and SEM. Kinetic experiments showed that the amount of crystal violet adsorbed increased with increasing temperature and equilibrium was reached at 12 h. Adsorption kinetics followed a pseudo-second-order model. The Arrhenius and Eyring models were used to obtain the activation energy and changes in free energy, enthalpy, and entropy of activation for the adsorption process. The calculated activation energy (14.14 kJ/mol) suggested physical adsorption of CV onto SMA. The equilibrium data were well fitted to the Langmuir and Sips isotherms. Maximum adsorption capacity was 692.1 mg/g at 45 °C. Thermodynamic parameters such as changes in free energy, enthalpy and entropy were also determined. [ABSTRACT FROM AUTHOR]

• The proposed SB fractionation strategy led to substantial savings of H 2 O 2. • Alkaline extraction after hydrothermal pretreatment led to high delignification. • The higher accessibility of pretreated SB led to an enzymatic conversion of 88.9%. • 190.8 L ethanol ton SB −1 were produced by fermentation using S. cerevisiae LBCM1047. • The anaerobic digestion of residual liquid streams produced 27.46 Nm3 CH4 ton SB −1. The fractionation of sugarcane bagasse (SB) by hydrothermal pretreatment (HP, autohydrolysis) followed by alkaline extraction (AE) and advanced oxidative pretreatment (AOP) for production of second-generation ethanol and biogas was investigated. The AOP of SB was optimized using a Doehlert design, varying the applied H 2 O 2 load, liquid-to-solid ratio (LSR), and time. The responses evaluated were yield (Y), residual cellulose (RC), delignification (DE), and enzymatic conversion (EC). The AE of SB pretreated by HP led to 61.8% DE (using 0.2 mol L−1 NaOH). This high lignin removal enabled substantial savings of H 2 O 2 in the AOP. The optimized AOP conditions led to 78% Y , 82.2% RC , 42.7% DE , and 88.9% EC (overall glucose yield of 60.9%). Fermentation of the enzymatic hydrolysate with Saccharomyces cerevisiae yielded 190.8 L ethanol ton SB −1. Biogas production by anaerobic digestion of residual liquid streams of the pretreatment steps yielded 27.46 NL CH4 kg SB −1. An energy balance was estimated for the SB fractionation. [ABSTRACT FROM AUTHOR]

• The anaerobic co-digestion (AcD) of sugarcane biorefinery wastes was investigated. • Hemicelluloses hydrolysate, yeast extract (YE), vinasse and SBFA were used in AcD. • Sugarcane bagasse fly ash (SBFA) act as an adsorbent for toxic compounds during AcD. • The nutritional supplements and alkalinity for AcD were provided by YE and SBFA. • A positive energy balance was obtained by the net energy generated by AcD system. In this study the anaerobic co-digestion (AcD) of sugarcane biorefinery by-products, i.e. hemicelluloses hydrolysate (HH) (obtained by hydrothermal pretreatment of sugarcane bagasse), vinasse, yeast extract (YE) and sugarcane bagasse fly ashes (SBFA), was optimized by means of biochemical methane potential experiments. The best experimental conditions of AcD (25–75% HH-to-vinasse mixture ratio; 1.0 g L−1 YE; 15 g L−1 SBFA and 100–0% HH-to-Vinasse; 1.5 g L−1 YE; 45 g L−1 SBFA) led to the production of 0.279 and 0.267 Nm3 of CH 4 per kg of chemical oxygen demand (COD) with an energy surplus of 0.43 and 0.34 MJ kg SB−1, respectively. Adsorption experiments using SBFA were carried out and showed this residue could adsorb up to 61.71 and 17.32 mg g−1 of 5-hydroxymethyl-2-furfuraldehyde and 2-furfuraldehyde, thereby reducing toxicity and improving biogas production. [ABSTRACT FROM AUTHOR]