Search

Vineyard pruning residues were subjected to alkaline peroxide treatment for delignification. Experimental conditions maximizing lignin removal were determined by using Box–Behnken statistical experiment design. NaOH/Biomass, H 2 O 2 /Biomass and retention time were chosen as independent variables and percent lignin removal was the objective function. Experiments were done at constant Solid/Liquid ratio of 0.1 (w/w) and 135 °C. All parameters were found to have significant effect on lignin removal. Complete delignification was obtained in 120 min at a NaOH/Biomass ratio of 1.10 and a H 2 O 2 /Biomass ratio of 0.65. The solid residue consisted of 95% total carbohydrate indicating significant carbohydrate enrichment after complete delignification. [ABSTRACT FROM AUTHOR]

Abstract: The steam pre-treatment with low severity preserves valuable biomass components, and further delignification with alkaline peroxide could improve hydrolysis. A combination of low severity steam pretreatment and alkaline peroxide post-treatment of Lespedeza stalks was investigated. The post-treatment of steam-pretreated Lespedeza stalks with alkaline peroxide significantly increased the cellulose content and changed the structure of the cellulose-rich fractions. A glucose yield of 503.5mgg−1 raw material from enzyme hydrolysis was obtained when the steam-pretreated material (184°C for 4min) was post-treated with 2% hydrogen peroxide at 60°C for 24h with a substrate concentration of 3.3%. Its hydrolysis yield is 88.8%, which is higher than that of samples processed by steam pretreatment alone (63.7%). The samples obtained by post-treatment with alkaline peroxide were found to have a smoother surface and looser structure in scanning electron microscopy images. The isolated lignin preparations had a yield range from 10.9 to 14.7 (% dry matter). The lignin was characterized by thermogravimetric analysis/differential thermal analysis, Fourier transform infrared spectroscopy, and gel permeation chromatography. Alkaline peroxide treatment increased the thermal stability of lignin, and decreased the amounts of all functional groups. Depolymerization and repolymerization occurred during the alkaline peroxide treatment. [Copyright &y& Elsevier]

So far, a large number of pretreatment methods have garnered significant attention aimed only at optimizing the reducing sugar and bioethanol yields. This study however, carried out pretreatment of sugarcane bagasse (SCB) using hydrothermal, organosolv, alkaline and alkaline peroxide pretreatment methods comparing their process performance. An evaluation of the energy consumption parameter during pretreatment showed lowest energy use (0.619 kWh/kg) during 5% alkaline peroxide pretreatment. The energy efficiency (0.162 kg bioethanol/kWh) was thus highest whereas the waste generation was lowest (38.895 kg waste/kg bioethanol) during alkaline peroxide pretreatment process. The solid biomass was utilized for enzymatic saccharification and bioethanol fermentation using SSF. Maximum enzyme efficiency and bioethanol yields achieved were 85.02% and 0.101 kg bioethanol/kg biomass respectively. Process performance evaluation can be projected to open up a new avenue for practical implementations of life cycle analysis (LCA) and techno-economic assessment aiding the circular bio-economy approach. [Display omitted] • Chemical pretreatment technologies investigated for process performance evaluation. • Energy efficiency and waste generation used to evaluate process performance. • 0.162 kg bioethanol/kWh- energy efficiency during alkaline peroxide pretreatment. • Also, lowest waste generation (38.895 kg waste/kg bioethanol) was recorded. • NaOH and H 2 O 2 at 5% (w/w) chemical concentration was most effective pretreatment. [ABSTRACT FROM AUTHOR]

White-rot fungi pretreatment is one of the most environment-friendly pretreatment methods because of low chemical and energy requirement. However, apart from time consuming, white-rot fungi treatment results in inefficient delignification and humin formation, both of which inhibit subsequent enzymatic hydrolysis. Combined alkaline treatment for partial depolymerization of residual lignin and dissolution of humin is an efficient option for the conversion of white-rot pretreated samples. In the work presented, combined treatments increased the enzymatic digestibility to 89.3%, compared with 10.6% for untreated sample and 12.9% for solely white-rot treated samples. Highest digestibility of cellulose was achieved after 8 weeks of white-rot treatment and alkaline treatment at 120 °C, whereas sugar yield was highest from sole alkaline treatment at 160 °C. The efficient conversion can be ascribed to synergistic interaction between white-rot and alkaline treatments, resulting in increased enzymatic accessibility of cellulose. Therefore, white-rot fungi treatment is a green process that can efficiently decrease energy consumption, and in combination with alkaline treatment is highly effective in promoting sugar conversion. [ABSTRACT FROM AUTHOR]

This work evaluates the feasibility of APMP (alkaline peroxide mechanical pulping) and CTMP (chemi-thermomechanical pulping) of wheat straw as small-scale, low-capital expenditure pulping process to produce high-yield pulps for fiber-based bioproducts. APMP and CTMP wheat straw pulps were characterized in terms of pulping yield, freeness, ISO brightness, and fiber morphology. Additionally, both pulps were evaluated for tissue paper applications and benchmarked against BEK (bleached eucalyptus kraft) market pulp. APMP wheat straw pulps presented higher yield (75.2 – 79.8 %) compared to CTMP (69.1 – 80.6 %), depending on cooking chemicals and chemical charge during the chemical impregnation stage. The final brightness of APMP pulps varied from 36.4 % to 37.8 % ISO when sodium hydroxide and hydrogen peroxide were used as pulping agents without additional chemical additives. However, the brightness of APMP pulps can be increased up to 49.7 % ISO by using additional chemical additives such as EDTA (chelating agent), sodium silicate (peroxide stabilizer), or by employing a multi-stage chemical impregnation strategy. Both pulps produced fibers with similar morphological properties. A comparison of tissue-making properties showed that APMP pulps produced bulkier handsheets with higher water absorption capacity and better softness than CTMP pulps. However, CTMP pulps exhibited a higher tensile index than APMP pulps for a given pulp freeness. The results indicate that non-wood fibers, such as those derived from wheat straw, could be a promising alternative for use in fiber-based bioproducts such as hygiene tissue. • Non-wood feedstock yields high-quality fibers for bio-products. • Chemo-mechanical pulping was evaluated on wheat straw. • Mechanical pulping is a small-scale process to produce high-yield non-wood pulps. • APMP wheat straw shows promise for tissue paper production. • CTMP wheat straw yields high-tensile strength fibers. [ABSTRACT FROM AUTHOR]

The paper reports some experimental results on the effect of different chemical modifications of Diss fibers on the properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) biocomposites involving alkaline, combined alkaline/peroxide and combined alkaline/silane treatments. The biocomposite samples loaded at 20 wt% were prepared by melt compounding. Scanning Electron Microscopy (SEM) showed a better fiber-matrix interaction between Diss fiber and matrix after surface fiber treatment. Differential Scanning Calorimetry (DSC) and X-ray Diffraction (XRD) results indicated an increase in crystallinity index of the biocomposites. In addition, the incorporation of Diss fibers treated with alkali-silane resulted in an improvement in Heat Deflection Temperature (HDT) and shore D hardness from 141.1 °C and 75.1–145.7°C and 86.2, respectively, in comparison with the neat matrix. This also agreed with the flexural properties results, which showed a significant increase in flexural modulus by almost 30 % compared to the neat PHBV. The same trend was observed for water absorption. Overall, combined alkali-silane treatment was found to be most efficient surface treatment method to develop strong interfacial adhesion between PHBV and Diss fiber, increasing the scope of application in manufacturing of light weight green composites. • Effect of various surface treatments on Diss fibers used as reinforcement in PHBV-based biocomposites. • Structural and properties characterization of Diss fibers and PHBV/Diss fibers biocomposite 80/20 (w/w). • Interesting Diss source of cellulosic reinforcing materials. [ABSTRACT FROM AUTHOR]

The pre-treatment step of lignocellulosic ethanol production is recognised as the most energy intensive part of the overall process. Key objectives are thus that pre-treatments should operate effectively at low to moderate temperatures and at high percentage solids, in order to minimise energy inputs. Chemical pre-treatment of BSG using alkaline reagents, at moderate process temperatures, was optimised in terms of sugar release following enzymatic saccharification of the pre-treated residues. An excess of Celluclast ® cellulase enzyme was used to compare various pre-treatments in terms of the % of theoretical sugars that could be liberated. Using alkaline peroxide (5% H 2 O 2 /NaOH at pH 11) up to 87% of the theoretical glucose yield (based on composition of the pre-treated residue) was attained following pre-treatment of BSG at 25% (w/v) solids loading for 5 h at 100 °C. Pre-treatment using 5% NaOH at 25% (w/v) solids loading for 12 h at 50 °C liberated 92% of theoretical glucose This pre-treatment remained effective with process times as short as 2 h (ca. 70% of theoretical glucose). For NaOH pre-treatments the extent of lignin removal from pre-treated residues broadly correlated with the efficacy of the pre-treatment in terms of final saccharification yields. However, for alkaline peroxide pre-treatments no such correlation was observed. Saccharified BSG was prepared following treatment with the optimised NaOH or alkaline peroxide pre-treatments and the resultant hydrolysates fermented with Saccharomyces cerevisiae . Fermentation performance was superior for the NaOH pre-treated samples relative to alkaline peroxide generated feedstocks with shorter lag phases and faster attenuation rates. Mean ethanol concentrations of ca. 17.3 g/L and 8.4 g/L were achieved for the NaOH and alkaline peroxide fermentations respectively which corresponded to 81% and 43% of theoretical ethanol yields. [ABSTRACT FROM AUTHOR]

In the context of using biomass-derived natural polymers in material synthesis, a new UV-shielding film essentially consisted of biodegradable lignocellulosic waste was successfully fabricated. Herein, the hierarchically processed corncob residue (CR) with various lignin content was achieved by alkaline peroxide treatment (0–4 wt%). The lignocellulose films (LFs) containing lignin were easily obtained by the dissolution of cellulose-rich solid residues in ZnCl 2 /CaCl 2 solvent followed by reconstitution with ethanol. The resulting LFs possessed tunable mechanical and UV-shielding properties, depending on the amount of lignin. CR-based film containing 6.5% lignin exhibited the relatively good mechanical property (a tensile strength of 26.9 MPa), high transmittance (66.2% at 550 nm) and haze (70.1%), and effective UV-shielding capacity (83.7% for UVB and 70.0% for UVA). This study provides a novel integrated process for the valorization of CR and a practical route for functional biomaterial production. • Corncob residue is processed to fabricate lignocellulose-based film. • Lignin content influences the mechanical and optical properties of the films. • CR-based films exhibit good UV-blocking capacity. • Sustainable, easily available, and low-cost films are produced from biomass wastes. [ABSTRACT FROM AUTHOR]

Abstract: This work evaluates the use of sugarcane bagasse (SCB) as a source of cellulose to obtain whiskers. These fibers were extracted after SCB underwent alkaline peroxide pre-treatment followed by acid hydrolysis at 45°C. The influence of extraction time (30 and 75min) on the properties of the nanofibers was investigated. Sugarcane bagasse whiskers (SCBW) were analyzed by transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) in air atmosphere. The results showed that SCB could be used as source to obtain cellulose whiskers and they had needle-like structures with an average length (L) of 255±55nm and diameter (D) of 4±2nm, giving an aspect ratio (L/D) around 64. More drastic hydrolysis conditions (75min) resulted in less thermally stable whiskers and caused some damage on the crystal structure of the cellulose as observed by XRD analysis. [ABSTRACT FROM AUTHOR]

• Mixed triploid poplar and acacia woodchips P-RC APMP was made. • The obtained pulp with the substitution of 50 wt% NaOH by MgO had an excellent bulk. • The bleaching effluent of the obtained pulp had a low COD. • The bleaching reaction rate depended on the concentration of bleaching reagents. • The magnitude of the dependent extent is [H 2 O 2 ] > [NaOH] > [MgO] > [Na 2 SiO 3 ]. In the present work, the H 2 O 2 bleaching with the substitution of 50 wt% NaOH by MgO as the alkali source in the high-consistency (HC) retention stage of mixed triploid poplar (Populus tomentosa Carr.) and acacia (Acacia confusa Merr.) woodchips P-RC APMP (preconditioning followed by refiner chemical treatment, alkaline peroxide mechanical pulp) was conducted. Meanwhile, the related bleaching reaction kinetics was well established. The obtained high-yield pulp presented a higher bleaching yield, improved bulk, favorable brightness and physical properties in comparison with the obtained pulp using 100 % NaOH as the alkali source. Most importantly, the chemical oxygen demand (COD) of the bleaching effluent was greatly decreased. The established bleaching kinetic equation is as following: dw dt = K [ H 2 O 2 ] 3.63 [ NaOH ] 1.08 [ MgO ] 0.57 [ Na 2 SiO 3 ] 0.05 w − 1.89 K = A·e –E/RT where the activation energy E =57.2 kJ/mol. It demonstrates that the bleaching reaction rate greatly depends on the concentration of primary bleaching reagents. The magnitude of the dependent extent is [H 2 O 2 ] > [NaOH] > [MgO] > [Na 2 SiO 3 ]. The rapid rise of the pulp brightness increment occurred in the first 35 min in the bleaching reaction. [ABSTRACT FROM AUTHOR]

Abstract: Fractionation of dhaincha (Sesbania aculeata), kash (Saccharum spontaneum) and banana stem (Musa Cavendish) was investigated by atmospheric formic acid pulping. Pulping of dhaincha, banana stem and kash was not satisfactorily delignified when the formic acid concentration was limited to 70%; even longer cooking time (120min) at this concentration did not produce pulp of lower lignin content. The marked effect of delignification was observed in case of 90% formic acid concentration. Peroxyformic acid effectively reduced the residual lignin of the formic acid pulp. In alkaline peroxide bleaching, formic acid pulp was bleached to 75–83% brightness depending on the nonwood. The strength properties were almost comparable to conventional pulp. The dhaincha pulp was stronger than the banana stem and kash pulp. The bleaching improved the strength properties of the pulp. Isolated lignin from formic acid spent liquor had higher syringyl unit than guaiacyl unit. Its β-O-4 bond was cleaved during formic acid pulping, which increased phenolic hydroxyl group. The lignin was formylated during pulping. The major devolatilization of formic acid lignin was occurred between 200 and 550°C as shown by TG graph. The xylose was the main sugar in water-soluble fractions of formic acid spent liquor that represented 50–60% of the content in original raw materials. [Copyright &y& Elsevier]

• A process was established for producing xylooligosaccharide (XOS) prebiotics. • XOS were made from hemicellulose (HC) of oil palm fruit bunch (OFB) fiber. • Recovery process for HC was optimized using Taguchi experiment design. • XOS were shown to support growth of two probiotic bacteria in vitro. • In coculture, the bacteria produced health-promoting short-chain fatty acids. Hemicellulose was recovered from oil palm empty fruit bunch (EFB) fiber and used for producing xylooligosaccharides (XOS) prebiotics. EFB fibers were treated sequentially with peracetic acid (PA) and alkaline peroxide (AP). The PA treatment removed ∼50 % lignin. The subsequent AP treatment recovered the hemicellulose. The AP treatment was optimized using Taguchi experiment design with L16 orthogonal array consisting of 5 factors (NaOH concentration, H 2 O 2 concentration, MgSO 4 concentration, incubation temperature, treatment time) and 4 levels. Data from 16 experimental runs showed that the main effect of the factors on percentage hemicellulose recovery was in the order: NaOH > MgSO 4 > incubation temperature > time > H 2 O 2. The optimal conditions for hemicellulose isolation were: 15 % w/v NaOH in the reaction system (3 g NaOH/g delignified EFB), 1% w/v MgSO 4 (0.2 g MgSO 4 /g delignified EFB), 45 °C incubation temperature and a 3 h reaction time. The PA-AP treatments solubilized nearly 53 % of the original dry mass of EFB. The enriched hemicellulose yield on EFB was 18.4 % by weight. Acid hydrolysis of the released hemicellulose produced xylose (44.1 %), glucose (17.6 %), arabinose (2.2 %), galactose (2.2 %), and mannose (4.4 %). Thermomyces lenuginosus xylanase (294.4 U L−1) was used to produce XOS from hemicellulose at 55 °C in a 12-h reaction. The XOS were assessed as substrates for two probiotic bacteria found in human gastrointestinal tract. The probiotic Lactobacillus plantarum WU-P19 utilized XOS better than Bifidobacterium bifidum TISTR 2129. Coculture of the two bacteria was shown to produce mixed fatty acids. [ABSTRACT FROM AUTHOR]