Search

The optimization of key simultaneous saccharification and fermentation (SSF) parameters for bioethanol production from phosphoric acid plus hydrogen peroxide pretreated paper mulberry wood was carried out under two isothermal scenarios; the yeast optimum and trade-off temperatures of 35 and 38 °C, respectively. The optimal conditions established for SSF at 35 °C (solid loading: 16%; enzyme dosage: 9.8 mg protein/g glucan; and yeast concentration: 6.5 g/L) achieved high ethanol titer and yield of 77.34 g/L and 84.60% (0.432 g/g), respectively. These corresponded to 1.2 and 1.3-folds increases, compared to the results of the optimal SSF at a relatively higher temperature of 38 °C. The information from this study would prove beneficial in reducing process energy demands to some extent, while also helping to achieve high levels of both ethanol concentration and yield that are desired in cellulosic ethanol production., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The abundantly released tail-gas from lignocellulose pretreatment with phosphoric acid plus hydrogen peroxide (PHP) was found to accelerate the aging of latex/silicone textural accessories of the pretreatment device. Inspired by this, tail-gas was utilized to control organic pollutants. Methylene blue (MB), as a model pollutant, was rapidly decolorized by the tail-gas, and oxidative degradation was substantially proven by full-wavelength scanning with a UV-visible spectrometer. The tail-gas from six typical lignocellulosic feedstocks produced 68.0-98.3% MB degradation, suggesting its wide feedstock compatibility. Three other dyes, including rhodamine B, methyl orange and malachite green, obtained 97.5-99.5% degradation; moreover, tetracycline, resorcinol and hexachlorobenzene achieved 73.8-93.7% degradation, suggesting a superior pollutant compatibility. In a cytotoxicity assessment, the survival rate of the degraded MB was 103.5% compared with 80.4% for the untreated MB, implying almost no cytotoxicity after MB degradation. Mechanism investigations indicated that the self-exothermic reaction in PHP pretreatment drove the self-generated peroxy acids into tail-gas. Moreover, it heated the pollutant solution and thermally activated peroxy acids as free radicals for efficient pollutant degradation. Here, a brand-new technique for degrading organic pollutants with a "Win-Win-Win" concept was purposed for lignocellulose valorization, pollutant control by waste tail-gas, and biofuel production., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Pretreating lignocellulosic biomass by phosphoric acid plus hydrogen peroxide (PHP) was integrated with recovering concentrated phosphoric acid (CPA), lignin, and treating phosphorus (P) wastewater. Results indicated no significant effects on cellulose recovery was observed by promoting ethanol addition, but CPA and lignin recovery were improved to 80.0% and 23.3%, respectively. Increasing water addition did not greatly affect CPA recovery (80.0-80.4%), and lignin recovery (22.8-23.6%). Consequently, the ratio of 11:1 (ethanol/PHP solution) and 4:1 (water/de-ethanol liquor) were suggested for solid/liquid separation and lignin precipitation. Average 86.0% CPA was recycled for pretreatment (≥11 runs) with average 96.3% cellulose-glucose conversion. A specially-developed biochar from crab shell was efficient on P removal with maximal adsorption capacity of 261.6 mg/g. Pretreating 1.0 kg wheat straw by 1.1 kg CPA harvested 155.0 g ethanol, 45.0 g high purity lignin and 4.9 kg P-rich biochar fertilizer. Recovering CPA, biochar-fertilizer and lignin, and P wastewater treatment made PHP pretreatment towards more sustainable and cleaner., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Phosphoric acid plus hydrogen peroxide (PHP) pretreatment was employed on wheat straw for ethanol conversion by simultaneous saccharification and fermentation (SSF) at high loadings. Results showed solid loading of PHP-pretreated wheat straw can be greatly promoted to 20%. Although more enzyme input improved ethanol conversion significantly, it still can be potentially reduced to 10-20 mg protein/g cellulose. Increasing yeast input also promoted ethanol conversion, however, the responses were not significant. Response surface method was employed to optimize SSF conditions with the strategy of maximizing ethanol conversion and concentration and minimizing enzyme and yeast input. Results indicated that ethanol conversion of 88.2% and concentration of 69.9 g/L were obtained after 120 h SSF at solid loading of 15.3%, and CTec2 enzyme and yeast were in lower input of 13.2 mg protein/g cellulose and 1.0 g/L, respectively. Consequently, 15.5 g ethanol was harvested from 100 g wheat straw in the optimal conditions., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Wheat straw was pretreated by phosphoric acid plus hydrogen peroxide (PHP) for enzymatic hydrolysis and ethanol fermentation at high solid loadings. Results indicated solid loading could reach 20% with 77.4% cellulose-glucose conversion and glucose concentration of 164.9g/L in hydrolysate, it even was promoted to 25% with only 3.4% decrease on cellulose-glucose conversion as the pretreated-wheat straw was dewatered by air-drying. 72.9% cellulose-glucose conversion still was achieved as the minimized enzyme input of 20mg protein/g cellulose was employed for hydrolysis at 20% solid loading. In the corresponding conditions, 100g wheat straw can yield 11.2g ethanol with concentration of 71.2g/L by simultaneous saccharification and fermentation. Thus, PHP-pretreatment benefitted the glucose or ethanol yield at high solid loadings with lower enzyme input. Additionally, decreases on the maximal cellulase adsorption and the direct-orange/direct-blue indicated drying the PHP-pretreated substrates negatively affected the hydrolysis due to the shrinkage of cellulase-size-accommodable pores., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Biochar (BC) produced from oak sawdust by slow pyrolysis was investigated to check the potential inhibition to early growth of tomato for phytotoxicity assessment. An inverted-U-shaped dose-response relationship between BC dosage and seed germination/seedling growth can be observed. Half maximal effective concentration (EC 50 ), based on the inhibition rate of root and stem length, was 65.7 and 74.0 g kg -1 , respectively. At the highest BC dosage of 80.0 g kg -1 , germination rate, root, and shoot length were notably inhibited by 34.9, 62.3, and 62.2% compared with their corresponding controls (without BC). Fluorescence intensity, indicating reactive oxygen species (ROS) generation in leaf and root, was 177.7 and 344.5% higher than the control. Similar results on H 2 O 2 content in leaf and root were observed as well. Besides, membrane leakage from the leaf and root cells was 2.1- and 1.3-fold higher than the corresponding controls. These results proved that BC exhibited significant phytotoxicity in the early growth stage of tomato. Unlike BC, the inhibitions on seed germination and seedling growth, the ROS accumulation, and the plasma membrane damage were not obvious with increasing La-BC dosage. These results indicated that BC phytotoxicity can be greatly mitigated by La involvement in pyrolysis, which was potentially associated with the reduced organic compounds and free radicals in La-BC. Besides, bio-available La in La-BC was partially involved in mitigating the phytotoxicity.

Wheat straw was pretreated by phosphoric acid plus hydrogen peroxide (PHP), in which temperature, time, and H 3 PO 4 proportion for pretreatment were investigated by using response surface method. Results indicated that hemicellulose and lignin removal positively responded to the increase of pretreatment temperature, H 3 PO 4 proportion, and time. H 3 PO 4 proportion was the most important variable to control cellulose recovery, followed by pretreatment temperature and time. Moreover, these three variables all negatively related to cellulose recovery. Increasing H 3 PO 4 proportion can improve enzymatic hydrolysis; however, reduction on cellulose recovery results in decrease of glucose yield. Extra high temperature or long time for pretreatment was not beneficial to enzymatic hydrolysis and glucose yield. Based on the criterion for minimizing H 3 PO 4 usage and maximizing glucose yield, the optimized pretreatment conditions was 40 °C, 2.0 h, and H 3 PO 4 proportion of 70.2 % (H 2 O 2 proportion of 5.2 %), by which glucose yielded 299 mg/g wheat straw (946.2 mg/g cellulose) after 72-h enzymatic hydrolysis.

Wheat straw was pretreated by PHP (the concentrated H3PO4 plus H2O2) to clarify effects of temperature, time and H3PO4 proportion on hemicellulose removal, delignification, cellulose recovery and enzymatic digestibility. Overall, hemicellulose removal was intensified by PHP comparing to the concentrated H3PO4. Moreover, efficient delignification specially happened in PHP pretreatment. Hemicellulose removal and delignification by PHP positively responded to temperature and time. Increasing H3PO4 proportion in PHP can promote hemicellulose removal, however, decrease the delignification. Maximum hemicellulose removal and delignification were achieved at 100% and 83.7% by PHP. Enzymatic digestibility of PHP-pretreated wheat straw was greatly improved by increasing temperature, time and H3PO4 proportion, and complete hydrolysis can be achieved consequently. As temperature of 30-40°C, time of 2.0 h and H3PO4 proportion of 60% were employed, more than 92% cellulose was retained in the pretreated wheat straw, and 29.1-32.6g glucose can be harvested from 100g wheat straw., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

In order to seek a high-efficient pretreatment path for converting lignocellulosic feedstocks to fermentable sugars by enzymatic hydrolysis, the concentrated H₃PO₄ plus H₂O₂ (PHP) was attempted to pretreat different lignocellulosic biomass for evaluating the pretreatment flexibility on feedstocks. Meanwhile, the responses of pretreatment to particle sizes were also evaluated. When the PHP-pretreatment was employed (final H₂O₂ and H₃PO₄ concentration of 1.77% and 80.0%), 71-96% lignin and more than 95% hemicellulose in various feedstocks (agricultural residues, hardwood, softwood, bamboo, and their mixture, and garden wastes mixture) can be removed. Consequently, more than 90% glucose conversion was uniformly achieved indicating PHP greatly improved the pretreatment flexibility to different feedstocks. Moreover, when wheat straw and oak chips were PHP-pretreated with different sizes, the average glucose conversion reached 94.9% and 100% with lower coefficient of variation (7.9% and 0.0%), which implied PHP-pretreatment can significantly weaken the negative effects of feedstock sizes on subsequent conversion., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Regenerated cellulose fibers (RCFs) are widely used biodegradable and eco-friendly materials made from woody biomass that can replace synthetic fibers. In this work, we explored the feasibility of fabricating RCFs using phosphoric acid with hydrogen peroxide (PHP)-treated wheat straw in an N, N-dimethylacetamide/lithium chloride (DMAc/LiCl) solvent system. The effects of upstream pretreatment conditions on the obtained cellulose-enriched fraction (CEF), the solubility of CEF in DMAc/LiCl, the mechanical properties of RCFs, and the interfacial interaction of residual lignin were systematically studied. CEF could be completely dissolved in DMAc/LiCl, and its wet spun RCFs had tensile strengths of 184 MPa and toughness values of 25 MJ/m3; it demonstrated remarkable wet strength (84 MPa), wet toughness (11 MJ/m3), and dyeing properties. The existence of residual lignin negatively affected the RCF mechanical properties; however, it enhanced its resistance to water infiltration. The present work provided a new approach for producing RCFs from woody biomass. [ABSTRACT FROM AUTHOR]

Background: Peroxyacetic acid involved chemical pretreatment is effective in lignocellulose deconstruction and oxidation. However, these peroxyacetic acid are usually artificially added. Our previous work has shown that the newly developed PHP pretreatment (phosphoric acid plus hydrogen peroxide) is promising in lignocellulose biomass fractionation through an aggressive oxidation process, while the information about the synergistic effect between H3PO4 and H2O2 is quite lack, especially whether some strong oxidant intermediates is existed. In this work, we reported the PHP pretreatment system could self-generate peroxyacetic acid oxidant, which mediated the overall lignocellulose deconstruction, and hemicellulose/lignin degradation. Results: The PHP pretreatment profile on wheat straw and corn stalk were investigated. The pathways/mechanisms of peroxyacetic acid mediated-PHP pretreatment were elucidated through tracing the structural changes of each component. Results showed that hemicellulose was almost completely solubilized and removed, corresponding to about 87.0% cellulose recovery with high digestibility. Rather high degrees of delignification of 83.5% and 90.0% were achieved for wheat straw and corn stalk, respectively, with the aid of peroxyacetic acid oxidation. A clearly positive correlation was found between the concentration of peroxyacetic acid and the extent of lignocellulose deconstruction. Peroxyacetic acid was mainly self-generated through H2O2 oxidation of acetic acid that was produced from hemicellulose deacetylation and lignin degradation. The self-generated peroxyacetic acid then further contributed to lignocellulose deconstruction and delignification. Conclusions: The synergistic effect of H3PO4 and H2O2 in the PHP solvent system could efficiently deconstruct wheat straw and corn stalk lignocellulose through an oxidation-mediated process. The main function of H3PO4 was to deconstruct biomass recalcitrance and degrade hemicellulose through acid hydrolysis, while the function of H2O2 was to facilitate the formation of peroxyacetic acid. Peroxyacetic acid with stronger oxidation ability was generated through the reaction between H2O2 and acetic acid, which was released from xylan and lignin oxidation/degradation. This work elucidated the generation and function of peroxyacetic acid in the PHP pretreatment system, and also provide useful information to tailor peroxide-involved pretreatment routes, especially at acidic conditions. [ABSTRACT FROM AUTHOR]

Effective valorization of lignin is crucial to achieve a sustainable, economic and competitive biorefinery of lignocellulosic biomass. In this work, an integrated process was proposed based on a concentrated phosphoric acid plus hydrogen peroxide (PHP) pretreatment to simultaneously facilitate cellulose digestibility and modify lignin as adsorbent. As a dominant constitutor of PHP pretreatment, H2O2 input and its influence on the overall fractionation/lignin modification performance was thoroughly investigated. Results indicated that wheat straw was fractionated more efficiently by increasing the H2O2 input. H2O2 input had a significant influence on the digestibility of the obtained cellulose-rich fraction whereby almost 100.0% cellulose-glucose conversion can be achieved even with only 0.88% H2O2 input. Besides, the adsorption capacity of lignin on MB was improved (74.3 to 210.1 mg g−1) due to the oxidative-modification in PHP pretreatment with H2O2 inputs. Regression analysis indicated that –COOH groups mainly governed the lignin adsorption (R2 = 0.946), which displayed the considerable adsorption capacities for typical cationic substances. This work shows a promising way to integrate the lignin modification concept into the emerging PHP pretreatment process with the dual goal of both cellulose utilization and lignin valorization. [ABSTRACT FROM AUTHOR]

A novel batch simultaneous saccharification and juice co-fermentation (SSJcF) process was investigated using mixtures of PHP (phosphoric acid plus hydrogen peroxide) pretreated wood and fruit juice of paper mulberry tree. All the different substrate mixture configurations evaluated under normal gravity SSJcF (total sugar titer of 180 g/L) significantly improved both ethanol concentration and yield compared to sole simultaneous saccharification and fermentation (SSF) of paper mulberry wood. Among the different mixing ratios, the feedstock mixture with equal sugar content from each substrate resulted in maximum ethanol concentration, yield and productivity of 77.1 g/L, 83.9 % and 1.1 g/L/h, respectively. The external additions of mineral nutrients also had no impact on fermentation performance of the mixture. Furthermore, SSJcF was evaluated under different levels of high gravity (HG) and very high gravity (VHG) conditions. The total sugar titer of 350 g/L at equal contributions from each substrate reached very high ethanol concentration of 147.0 g/L, with yield and productivity of 82.3 % and 1.5 g/L/h, respectively. By implication, the PM wood and fruit juice mixture could serve as suitable low-cost and non-food feedstock alternative to the typical use of sugary and/or starchy feedstocks for VHG fermentation. [Display omitted] [ABSTRACT FROM AUTHOR]

Lignin acted as phenolic polymer is a sustainable substitute for phenol to synthesize lignin-phenol-formaldehyde (LPF). Here, PLPF resins were prepared with unmodified PHP-lignin derived from phosphoric acid plus hydrogen peroxide (PHP) pretreatment of biomass waste, the PHP-lignin has plentiful hydroxyl structure and is beneficial to the polymerization with formaldehyde. Meanwhile, ALPF resin synthesized with alkali lignin abundantly produced from pulp and paper industry was also included. The feasibility of lignin as a substitute for phenol, the application of the synthesized PLPF resin in particleboard production and the obstacle on the high-value utilization of waste lignocellulosic biomass due to the existence of the resin adhesive were evaluated. Results indicated that the resins were successfully synthesized when phenol was substituted by 25% lignin. The basic properties, including solid content, free phenol content, free formaldehyde content, viscosity and adhesion performance all met Chinese National Standard (GB/T 14732–2006) of phenol-formaldehyde (PF) resin. The shaped particleboard with PLPF resin usage ranged from 5% to 15% all had good dimensional stability and solvent resistance. Finally, we verified the resin adhesive in the particleboard would greatly influence its enzymatic hydrolysis performance. The cellulose-glucose conversion of hydrothermal pretreated particleboard was merely 18.3%. Detoxification was the first and most important step in the subsequent high-value utilization of waste particleboard, and alkali pretreatment suggested a possible way to eliminate the negative effects, which could improve cellulose-glucose conversion to 57.8%. [Display omitted] • LPF resin was successfully synthesized with unmodified PHP technical lignin. • The properties of LPF resin all met Chinese National Standard of PF resin. • LPF resin had the potential application in practical particleboard production. • Alkali pretreatment promoted high value utilization of waste particleboard with resin. [ABSTRACT FROM AUTHOR]

In order to seek a possible path for utilization bottom ash, the solid waste from biomass incineration for power generation, its basic characteristics were investigated, and removing methylene blue (MB) from aqueous solution was attempted as well. Results indicated bottom ash dominantly contained Si and Ca-related minerals with >35 mineral elements, meanwhile, it was typically characterized by alkalinity (pH of 9.5) and low specific surface area (14.5 m 2 /g). As the only bottom ash was employed for removing MB, removal efficiency was lower than 44%, however, it was greatly improved to 100% as hydrogen peroxide was supplemented (final concentration of 4.0%). Based on the elucidated mechanisms, Fenton-like reaction was triggered by bottom ash, which was dominantly responsible for removing MB, rather than the adsorption by bottom ash. Besides, increasing reaction temperature and duration dramatically promoted MB removal by bottom ash with the aid of hydrogen peroxide (HBA). A great promotion on MB removal from 92.3 mg/g to 143.9 mg/g was achieved as pH was adjusted from 2.0 to 5.0, indicating MB removal was pH-dependent. The maximum removal of 260.9 mg/g was achieved by HBA at a relatively high initial MB concentration of 2000.0 mg/L, suggesting a great potential in treating dye wastewater by functionalizing bottom ash with the aid of hydrogen peroxide. Moreover, the released heavy metals and derived by-products from MB removal were acceptable in consideration of their potential environmental risks. Thus, the current work offers a new path to valorize the solid waste in biomass electricity generation plant. [ABSTRACT FROM AUTHOR]

Agriculture and forestry yield enormous lignocellulosic biomass resources to produce bioenergy and bioproducts. To fully convert lignocellulosic biomass into high-value chemical components and manufactured products, phosphoric acid plus hydrogen peroxide (PHP) pretreatment was selected to fractionate them into cellulose-rich, water-soluble polysaccharides, and lignin fractions, and further upgraded into biofuel and biomaterials correspondingly. Results showed that the recalcitrant structure of the employed lignocellulose can be well disrupted the PHP, by which almost 100 % hemicellulose and 50.5–83.6 % lignin in these lignocellulosic biomasses can be removed. Correspondingly, the accessibility of cellulose hydrolytic enzymes was enhanced and achieved 100 % cellulose-glucose conversion, thus maximumly producing 18.4 g of bioethanol from 100 g of poplar hardwood. The acid hydrolysis ability of PHP facilitated the production of water-soluble polysaccharides with a high carbohydrate purity (98.3 %). The oxidation ability of PHP introduced additional carboxylic groups and aliphatic chains in lignin, which enhanced the amphiphilic properties of lignin to form uniform and stable lignin nanoparticles. The tailored PHP multiple product platform is thus applicable to achieve full conversion of agriculture and forestry residues into bioproducts as a sustainable biorefinery. [Display omitted] • Maximum converted lignocellulose waste into three high value-added bioproducts. • Multifunctional PHP technology allowed the facile upgradation of lignocellulose. • The maximum ethanol yield achieved at 18.4 g from 100 g lignocellulose by SSF. • The resulting high-value water soluble-polysaccharides exhibited high purity. • Mixed aromatic-aliphatic structure enhanced the amphiphilicity of lignin. [ABSTRACT FROM AUTHOR]

Paper mulberry wood contains a high cellulose content of 59%, making it a potentially excellent feedstock for recovery of fermentable sugar used in bioethanol production. This potential was usefully exploited by establishing the optimal phosphoric acid plus hydrogen peroxide pretreatment of its woods using the response surface methodology. Pretreatment temperature, H 3 PO 4 proportion in pretreatment mixture, and time significantly corelated with the removal of non-cellulosic polymers, cellulose recovery, enzymatic hydrolysis of the recovered cellulose, and glucose yield. At the optimized conditions of 34.7 ⁰C, 71.3% w/w H 3 PO 4 proportion (the corresponding H 2 O 2 proportion of 4.84% w/w), and 3.3 h, there were 97% biomass delignification, 100% hemicellulose removal, and high recovery of a cellulose-rich substrate characterized by decreased crystallinity, enhanced porosity, and complete glucose digestibility. The obtained high glucose yield of 493 mg/g raw wood was comparable to the best-reported yields from short-rotation woody energy crops. [Display omitted] • PM wood is outstandingly rich in cellulose for conversion to fermentable sugar. • PHP pretreatment was optimized for PM wood via Response Surface Methodology. • Cellulose hydrolysis was nearly 100% with high glucose yield of 493 mg/g-raw wood. • Glucose yield was on par with best reports from typical woody energy plants. [ABSTRACT FROM AUTHOR]

A newly developed PHP (phosphoric acid plus hydrogen peroxide) pretreatment for lignocellulose is integrated to be a multi-product platform for bioethanol, lignin, and ultra-high surface area carbon; the performances of this multi-product strategy are investigated in this work. Based on PHP pretreatment platform, 100.0 g wheat straw yield 16.0 g ethanol from the cellulose fraction, and 7.2 g high purity lignin can be recovered from the derived liquid fraction in pretreatment. Activated carbon (PHPK-800) with ultra-high surface area of 3291 m2 g−1 can be produced from the water-soluble fractions derived from pretreatment. As electrode material for supercapacitor, PHPK-800 displays an excellent specific capacitance of 303.5 F g−1 at 0.5 A g−1, and retains 87.0% of initial specific capacitance with more than 95.0% coulomb efficiency after 5000 cycles. The fabricated symmetric supercapacitor harvests an excellent energy density of 13.2 Wh kg−1 with 199.9 W kg−1 power density. Besides, a superior CO 2 adsorption capability of 4.61 mmol g−1 is achieved by activated carbon of PHPK-700. According to these performances, PHP pretreatment platform is promising for converting lignocellulose into bioethanol, lignin and carbons by the biomass full utilization to achieve a more sustainable lignocellulosic refinery. • Efficient lignocellulose pretreatment with yielding ultra-high surface area carbon. • 100.0 g wheat straw yielded considerable ethanol of 16.0 g after pretreatment of PHP. • 7.2 g high pure lignin with low molecular weight was yielded from 100 g wheat straw. • High specific surface area carbons were featured with a large number of micropores. • Resultant carbons displayed an excellent specific capacitance and CO 2 adsorption. [ABSTRACT FROM AUTHOR]