Combined Hydrolysis Factor Research Articles

Sustainable acid hydrotropic fractionation for bamboo-based nanofilms with unparalleled hydrophobicity and UV resistance

Bamboo, as an important biomass raw material, has a very favorable prospect for Nature-based Solution. Here we provide a method to prepare bamboo-based lignocellulosic nanofibrils (LCNFs) and films with excellent impedance performances by p-toluenesulfonic acid (p-TsOH) under mild condition. The combined delignification factor (CDF) and combined hydrolysis factor (CHF) were introduced to regulate the hydrolysis severity. The resultant LCNFs with uniform diameter retained a plentiful reactivity without surface functional group changing. The ascendant thermal stability (Tmax > 360 °C) of the LCNFs were also obtained. The films made by the LCNFs can block about 99 % UV light with transparency greater than 50 % which exhibited remarkable UV resistance in both UVA and UVB regions. Furthermore, the films presented excellent hydrophobic stability which showed large contact angles (water, 89–99°) and maintained at 64° after 300 s. These properties make bamboo-based materials substitute bamboo for plastics and can be used in aviation, construction, automotive industry, packaging and many other fields, conforming to international initiatives.

Furnishing autohydrolyzed poplar weakly alkaline P-RC APMP to make lightweight coated base paper

This work investigated the effects of autohydrolysis pretreatment severity on poplar (Populus tomentosa Carr.) woodchips used to make a type of high-yield pulp (HYP) known as preconditioning followed by refiner chemical treatment, alkaline peroxide mechanical pulp (P-RC APMP). It also investigated the ratios for partial-ly replacing sodium hydroxide (NaOH) with magnesium oxide (MgO) in the high-consistency (HC) retention stage of the P-RC APMP process on the obtained HYP’s properties. The results show that the pretreatment severity of autohydrolysis at combined hydrolysis factor (CHF) = 10.77 and the 50 wt% ratio for partially substituting NaOH with MgO were the optimum conditions for making light-weight coated (LWC) base paper. Compared to the conventional P-RC APMP, the optimized P-RC APMP had similar bulk and higher tensile, burst, and tear indices, as well as opacity, but a slightly lower ISO brightness. When the optimized P-RC APMP and commercial softwood bleached sulfate pulp (SBKP) were blended to make LWC base paper, the most favorable pulp furnish was comprised of 50% optimized P-RC APMP and 50% commercial SBKP. The obtained LWC base paper handsheet had better bulk, and its other properties could also meet the require-ments of LWC base paper.

Kinetic Analysis of Pulping of Rice Straw with p-Toluene Sulfonic Acid.

The kinetics of pulping of rice straw was studied with p-toluenesulfonic acid (p-TsOH). Pulping with 50% p-TsOH aqueous solution was performed at 70–100 °C for 0–360 min. The results showed that the delignification reaction could be divided into two phases: the bulk delignification phase and the supplementary delignification phase. Lignin dissolution was the main process in the bulk delignification stage, accompanied by the degradation of a small amount of carbohydrates. In the supplementary delignification stage, the delignification rate was low and carbohydrate degradation was severe. The degradation of carbohydrates is mainly based on the dissolution of hemicellulose. A combined delignification factor (CDF) and a combined hydrolysis factor (CHF) were used to compare severity-based kinetic analyses. The results showed that the degradation process for lignin and hemicellulose can be well-fitted using CDF and CHF models. The fitted results show that the activation energy of the hemicellulose loss reaction and delignification reaction was 68.21 and 46.05 kJ/mol, respectively. Therefore, the use of p-TsOH for pulping is a technology with very broad application prospects.

Using γ-valerolactone and toluenesulfonic acid to extract lignin efficiently with a combined hydrolysis factor and structure characteristics analysis of lignin

A method for isolating components of lignocellulose in hybrid poplar by using an organic solvent (γ-valerolactone) in combination with a solid organic acid (p-toluenesulfonic acid) is studied here. The combined hydrolysis factor (CHF) was used to measure the severity of the pretreatment conditions and to find the optimal reaction conditions (CHF = 54.99) by judging enzymatic saccharification and characterization of lignin residual. At this pretreatment strength, 91.67% hemicellulose and 86.14% lignin in lignocellulose were effectively removed, and the enzymatic hydrolysis of cellulose residue reached 84.84%. Hemicellulose was hydrolyzed to 4.39 g L−1 of xylose, and a portion was converted to 2.95 g L−1 of furfural and 3.59 g L−1 of acetic acid. The molecular weight, polydispersities and phenolic hydroxyl groups content of the isolated lignin were 1587 g mol−1, 1.04 and 3.64 mmol g−1 respectively, which indicated that the lignin had the potential to be a phenolic resin material and wood polyurethane foam. In summary, this method effectively separated three components of lignocellulose and obtained high purity cellulose and lignin.

Color evolution of poplar wood chips and its response to lignin and extractives changes in autohydrolysis pretreatment

Combining chemi-mechanical pulping with autohydrolysis pretreatment is an efficient and value-added utilization approach for lignocellulosic biomass in paper industry. To further promote the utilization of autohydrolyzed biomass in chemi-mechanical pulping, the color evolution of poplar wood chips in autohydrolysis pretreatment and its chromogenic mechanism were investigated by using CIELab color system, FT-IR, NMR and GPC. The results showed that the total color difference ΔE* increased obviously, which were remarkable as the combined hydrolysis factor (CHF) increased. The lignin content led to a more significant influence on the color of poplar wood chips than the extractives. The autohydrolysis pretreatment with a higher CHF accelerated the degradation and subsequent condensation of lignin, resulting in the formation of chromophoric groups, such as Hibbert ketone, quinones and quinone methides. It is of great significance for biomass refinery and paper industry to reveal the color evolution of poplar wood chips caused by autohydrolysis pretreatment from the point of view of chemical components' structure.

An optimum combined hydrolysis factor enhances hybrid Pennisetum pretreatment in bio-conversion

It is important to limit the formation of inhibitors when bio-refining lignocellulose for bioethanol production by steam explosion pretreatment. In this research, we found steam explosion with sulfite (SES) was an effective and efficient pretreatment for hybrid Pennisetum which was crossed by Pennisetum americanum and P.purpureum (Pennisetum americanum × P.purpureum) bio-conversion. The combined hydrolysis factor (CHF) derived from the kinetic models of hemicellulose hydrolysis and inhibitors formation was a useful indicator of pretreatment severity for a steam explosion with sulfite (SES) pretreatment. The apparent activation energy of hybrid Pennisetum pretreated by SES fitting with CHF (CHFses) was ~ 90 kJ/mol. CHFses can be used as predicting hemicellulose dissolution and substrate enzymatic digestion (SED), as well as balancing the trade-off between xylan remaining (XRses) and inhibitor formation. The correlation between CHFses and XRses was XRses = 0.78e−CHFses + 0.22e−0.282CHFses, and the relationship between XRses and SED was SED = $$28 + 221e^{{-X}_{R}ses/0.04}$$ . The xylan removal can reach up to 90% under mild conditions (temperature, pressure, and so on.) and was linearly related to enzymatic hydrolysis. CHFses determined in this study were effective in the experimental design of pretreatment for bioconversion of hybrid Pennisetum.

Using a combined hydrolysis factor to balance enzymatic saccharification and the structural characteristics of lignin during pretreatment of Hybrid poplar with a fully recyclable solid acid

In this study, a new pretreatment strategy for lignocellulosic was developed using a fully recyclable solid acid, Toluenesulfonic acid (p-TsOH). A combined hydrolysis factor (CHF) as a pretreatment severity was used to balance enzymatic saccharification and the structural characteristics of lignin. The results from degradation of carbohydrates, enzymatic hydrolysis of cellulose and characterization of lignin by FT-IR, 31P NMR, GPC, 2D-HSQC NMR indicated that a CHF of approximately 3.90 was the optimal pretreatment severity to facilitate enzymatic saccharification and the potential serviceability of lignin. Then approximately 90% of the xylan was removed to result in a reasonable sugar yield of 76%. Residual lignin showed low molecular weight (Mw, 5783g/mol), narrow polydispersities (Mw/Mn, 1.10) and high content of phenolic hydroxyl groups (3.702mmol/g); it may be a potential feedstock for phenol monomer and polymeric materials production. In short, this process was regarded as a promising approach to achieve an efficient conversion of lignocellulosic biomass to sugar products and lignin-based materials.

Tailored and Integrated Production of Carboxylated Cellulose Nanocrystals (CNC) with Nanofibrils (CNF) through Maleic Acid Hydrolysis

AbstractThis study demonstrates the feasibility of tailored and integrated production of carboxylated cellulose nanocrystals (CNC) with nanofibrils (CNF) from bleached pulp fibers through hydrolysis using a recyclable dicarboxylic acid. Hydrolysis experiments were conducted using ranges of 15–75 wt % maleic acid concentrations, 60–120 °C temperatures, and 5–300 min reaction times. Maleic acid esterified cellulose resulted in carboxylated CNC and CNF. Furthermore, the acid‐hydrolysis solubilized xylan and depolymerized cellulose, which substantially reduced the energy input for the production of CNF through subsequent mechanical fibrillation. A combined hydrolysis factor (CHF), a measure of hydrolysis severity, was developed to map xylan dissolution and cellulose depolymerization over the entire reaction space. It was found that CHF can be used to predict the morphological and chemical properties of the resultant CNC and CNF, independent of the individual reaction process variables. This is important for process scale‐up design in order to tailor the properties of CNC and CNF for specific applications. With the low temperature hydrolysis and low energy input in mechanical fibrillation, along with the recyclability of maleic acid, the presented process has promise of achieving commercial success in the low‐cost and sustainable production of CNC and CNF.

Understanding Longitudinal Wood Fiber Ultra-structure for Producing Cellulose Nanofibrils Using Disk Milling with Diluted Acid Prehydrolysis.

Here we used dilute oxalic acid to pretreat a kraft bleached Eucalyptus pulp (BEP) fibers to facilitate mechanical fibrillation in producing cellulose nanofibrils using disk milling with substantial mechanical energy savings. We successfully applied a reaction kinetics based combined hydrolysis factor (CHFX) as a severity factor to quantitatively control xylan dissolution and BEP fibril deploymerization. More importantly, we were able to accurately predict the degree of polymerization (DP) of disk-milled fibrils using CHFX and milling time or milling energy consumption. Experimentally determined ratio of fibril DP and number mean fibril height (diameter d), DP/d, an aspect ratio measurer, were independent of the processing conditions. Therefore, we hypothesize that cellulose have a longitudinal hierarchical structure as in the lateral direction. Acid hydrolysis and milling did not substantially cut the “natural” chain length of cellulose fibrils. This cellulose longitudinal hierarchical model provides support for using weak acid hydrolysis in the production of cellulose nanofibrils with substantially reduced energy input without negatively affecting fibril mechanical strength.

Reaction Kinetics Based Optimization of Furfural Production from Corncob Using a Fully Recyclable Solid Acid

To achieve green processing through recycling catalysts, this study demonstrated a commercial solid acid toluenesulfonic acid (p-TsOH) for furfural production from corncob. Acid recyclability study indicate that crystalized p-TsOH was highly effective for furfural production. A kinetic based reaction severity, combined hydrolysis factor (CHF), was used to develop a furfural predictive model with the consideration of loss through degradation. Furfural yield of approximately 75% theoretical was achieved in a CHF range between 830 and 1850.

High Titer Ethanol and Lignosulfonate Production from SPORL Pretreated Poplar at Pilot Scale

Poplar NE222 (Populus deltoides Bartr. ex Marsh × P. nigra L.) wood chips were pretreated in a 390 L pilot-scale rotating wood-pulping digester using a dilute sulfite solution of approximately pH  1.8 at 160°C for 40 min for bioconversion to ethanol and lignosulfonate (LS). An estimated combined hydrolysis factor (CHF) of 3.3 was used to scale the pretreatment temperature and time from laboratory bench scale experiments, which balanced sugar yield and inhibitor formation to facilitate high titer ethanol production through fermentation using S. cerevisiae YRH400 without detoxification. A terminal ethanol titer of 43.6 g L-1 with a yield of 247 L tonne wood-1 was achieved at total solids loading of 20%. The relatively low ethanol yield compared with yield from SPORL-pretreated softwoods was due to inefficient utilization of xylose. The LS from SPORL has a substantially higher phenolic group (Ph-OH) content although it is less sulfonated and has a lower molecular weight than a purified commercial softwood LS, and therefore has potential for certain commercial markets and future novel applications through further processing.

Using a combined hydrolysis factor to optimize high titer ethanol production from sulfite-pretreated poplar without detoxification

Sulfite pretreatment to overcome the recalcitrance of lignocelluloses (SPORL) was applied to poplar NE222 chips in a range of chemical loadings, temperatures, and times. The combined hydrolysis factor (CHF) as a pretreatment severity accurately predicted xylan dissolution by SPORL. Good correlations between CHF and pretreated solids enzymatic digestibility, sugar yield, and the formations of furfural and acetic acid were obtained. Therefore, CHF was used to balance sugar yield with the formation of fermentation inhibitors for high titer ethanol production without detoxification. The results indicated that optimal sugar yield can be achieved at CHF=3.1, however, fermentation using un-detoxified whole slurries of NE222 pretreated at different severities by SPORL indicated CHF≈2 produced best results. An ethanol titer of 41g/L was achieved at total solids of approximately 20wt% without detoxification with a low cellulase loading of 15FPU/g glucan (27mL/kg untreated wood).

Pilot-scale demonstration of SPORL for bioconversion of lodgepole pine to bioethanol and lignosulfonate

Abstract The process sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL) has been the focus of this study. Pilot-scale (50 kg) pretreatment of wood chips of lodgepole pine (Pinus contorta Douglas ex Loudon) killed by mountain pine beetle (Dendroctonus ponderosae Hopkins) were conducted at 165°C with a dilute sulfite solution of pH 2 for bioconversion to ethanol and lignosulfonate (LS). The pretreatment duration was optimized in laboratory bench scale experiments with a certain severity based on a combined hydrolysis factor (CHF). The sodium bisulfite loading was 8% and the liquor to wood ratio 3. The pretreated solids were disk milled together with the spent liquid and the resultant slurry with a 25% solids content was directly (without detoxification) submitted to a simultaneous enzymatic saccharification and fermentation (SSF) with Saccharomyces cerevisiae YRH400 at cellulase loading of 35 ml kg-1 of untreated wood. At solids loading of 20%, the alcohol yield was 288 l t-1 wood (with a final concentration of 52.2 g l-1), which corresponds to a 72.0% theoretical yield based on total glucan, mannan, and xylan. The LS from SPORL was highly sulfonated and its molecular weight was lower than that of a purified commercial softwood LS, and therefore it has a high potential as a directly marketable co-product.

Bioconversion of Beetle-Killed Lodgepole Pine Using SPORL: Process Scale-up Design, Lignin Coproduct, and High Solids Fermentation without Detoxification

Mountain pine beetle killed Lodgepole pine (Pinus contorta Douglas ex Loudon) wood chips were pretreated using an acidic sulfite solution of approximately pH = 2.0 at a liquor to wood ratio of 3 and sodium bisulfite loading of 8 wt % on wood. The combined hydrolysis factor (CHF), formulated from reaction kinetics, was used to design a scale-up pretreatment on 2000 g wood chips at a relatively low temperature of 165 °C that reduced furan formation and facilitated high solids saccharification and fermentation. The pretreated solids and liquor were disk milled together to result in a biomass whole slurry of 25% total solids. The whole biomass slurry was directly used to conduct simultaneous enzymatic saccharification and combined fermentation (SSCombF) using a commercial cellulase and Saccharomyces cerevisiae YRH400 without detoxification. A terminal ethanol titer of 47.1 g L–1 with a yield of 306 L (tonne wood)−1, or 72.0% theoretical, was achieved when SSCombF was conducted at an unwashed solids loading of...

Robust enzymatic saccharification of a Douglas-fir forest harvest residue by SPORL

Forest harvest residues can be a cost-effective feedstock for a biorefinery, but the high lignin content of forest residues is a major barrier for enzymatic sugar production. Sulfite pretreatment to overcome strong recalcitrance of lignocelluloses (SPORL) was applied to a Douglas-fir (Pseudotsuga menziesii (Mirb) Franco var. menziesii) forest residue in a range of sulfite and acid loadings at 165 °C for 75 min with liquid to wood ratio of 3:1. Sodium bisulfite and sulfuric acid charge as mass fraction of oven dry biomass of 12% and 2.21%, respectively, was optimal in terms of enzymatic cellulose saccharification, sugar yield and formation of hydroxymethylfurfural (HMF) and furfural. Enzymatic glucose yield was 345 g kg−1, or equivalent to 82.3% of theoretical at a cellulase (CTec2) dosage of 15 filter paper unit (FPU) per gram of glucan. HMF and furfural formation were low at approximately 2.5 g L−1 each in the pretreatment hydrolyzate. Delignification was important to achieve good cellulose saccharification efficiency, however, approximately 80–90% hemicellulose removal is also required. Substrate enzymatic digestibility (SED) was found to correlate to a combined parameter Z(CHF) of delignification and hemicellulose dissolution well, suggesting that the combined hydrolysis factor (CHF) – a pretreatment severity measure – can be used to predict saccharification of forest residue for scale-up studies to reduce numbers of experiments.

Quantitative predictions of bioconversion of aspen by dilute acid and SPORL pretreatments using a unified combined hydrolysis factor (CHF)

A combined hydrolysis factor (CHF) was developed to predict xylan hydrolysis during pretreatments of native aspen (Populus tremuloides) wood chips. A natural extension of previously developed kinetic models allowed us to account for the effect of catalysts by dilute acid and two sulfite pretreatments at different pH values. When xylan is modeled as two fractions with different hydrolysis rates, previously identified as fast and slow xylan, the model closely matches the experimental data. Extent of xylan hydrolysis is strongly correlated with pretreatment solids yield, energy consumption for size reduction, and substrate enzymatic digestibility (SED). Composition of the pretreatment hydrolysate was less correlated with extent of hydrolysis due to carbohydrate decomposition reactions. Substrate cellulose enzymatic conversion and enzymatic hydrolysis glucose yield can be predicted to approximately 10% accuracy using CHF alone.