Simultaneous saccharification of hemicellulose and cellulose of corncob in a one-pot system using catalysis of carbon based solid acid from lignosulfonate

The drive towards sustainable chemistry has inspired the development of active solid acids as catalysts and ionic liquids as solvents for an efficient release of sugars from lignocellulosic biomass for future biorefinery practices. Carbon-based solid acid (SI–C–S–H2O2) prepared from sodium lignosulfonate, a waste of the paper industry, was used with water or ionic liquid to hydrolyze corncob in this study. The effects of various reaction parameters were investigated in different solvent systems. The highest xylose yield of 83.4% and hemicellulose removal rate of 90.6% were obtained in an aqueous system at 130 °C for 14 h. After the pretreatment, cellulase was used for the hydrolysis of residue and the enzymatic digestibility of 92.6% was obtained. Following these two hydrolysis steps in the aqueous systems, the highest yield of total reducing sugar (TRS) was obtained at 88.1%. Further, one-step depolymerization and saccharification of corncob hemicellulose and cellulose to reducing sugars in an IL-water system catalyzed by SI–C–S–H2O2 was conducted at 130 °C for 10 h, with a high TRS yield of 75.1% obtained directly. After recycling five times, the solid acid catalyst still showed a high catalytic activity for sugar yield in different systems, providing a green and effective method for lignocellulose degradation

Structural changes and enzymatic saccharification intensification of spent mushroom substrate after ball milling pretreatment

The spent mushroom substrate (SMS) after harvesting mushroom can be regarded as a bio-treated lignocellulose, which offsets the low economic benefit of simple biological pretreatment. In this study, SMS was treated with mechanical pulverization followed by ball milling for enzymatic saccharification. The enzymatic hydrolysis efficiency (EHE) of two-step milled SMS is approximately 103% higher than that of only mechanically pulverized SMS. The smaller initial particle size of SMS could obtain higher EHE in a shorter milling time but not reach the maximum EHE with the increase of milling time. The proper rather than longer time for ball milling is better for improving enzymatic hydrolysis of SMS. SEM and XRD examination reveal that the ball milling pretreatment significantly changes the surface morphologies and reduces the crystallinities of the samples. BET detection indicates that long-time ball milling could decrease the specific surface area of SMS, which might be the reason for the EHE decrease of SMS milled for longer time. The 8-h ball milling made the EHE of SMS increase from 38.75 to 75.71% with the addition of 0.5% (v/v) Tween 80. It provides an environment-friendly pretreatment way without waste liquor generation for improving enzymatic saccharification of lignocellulose

Synergistic Enhancement Effect of Compound Additive of Organic Alcohols and Biosurfactant on Enzymatic Hydrolysis of Lignocellulose

The insufficient of lignocellulose degradation enzymes, such as cellulase and hemicellulase, is the major obstacle that hinders the bioconversion of lignocellulosic biomass to monosaccharides, especially during the woody biomass hydrolysis process. The addition of additives has received significant attention due to their enhancement of the enzymatic degradation efficiency of lignocellulose. In the present study, a combination of organic alcohols and a biosurfactant could synergistically enhance the saccharification of the cellulose substrate of Avicel, as well as that of pretreated poplar. Results showed that compound additives can greatly improve the conversion rate of enzymatic hydrolysis. The combination of 0.1% (v/v) n-decanol and 1% (v/v) sophorolipid dramatically increased the poplar enzymatic conversion rate from 17.9% to 85%, improving it by 67.1%. Enzyme-rich Hypocrea sp. W63 was fermented to obtain beta-glucosidase (BGL) and xylanase (XYL), which were used as auxiliary enzymes during enzymatic hydrolysis. It was found that the effects of such a combination of additives improved the filter paper activity, stability, and longevity, helping in the recovery of the cellulase cocktail. The compound additives associated with the commercial cellulase and Hypocrea sp. W63 enzyme solution formed an excellent formula for improving the stability of BGL and XYL. The results provide insight into compound additives and the use of a cellulase and auxiliary enzyme cocktail to improve enzymatic hydrolysis for lignocellulose conversion into biofuels

Significantly Enhanced Self-Cleaning Capability in Anatase TiO₂ for the Bleaching of Organic Dyes and Glazes

In this study, the Mg2+-doped anatase TiO2 phase was synthesized via the solvothermal method by changing the ratio of deionized water and absolute ethanol Vwater/Vethanol). This enhances the bleaching efficiency under visible light. The crystal structure, morphology, and photocatalytic properties of Mg-doped TiO2 were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, N2 adsorption-desorption, UV-Vis spectroscopy analysis, etc. Results showed that the photocatalytic activity of the Mg2+-doped TiO2 sample was effectively improved, and the morphology, specific surface area, and porosity of TiO2 could be controlled by Vwater/Vethanol. Compared with the Mg-undoped TiO2 sample, Mg-doped TiO2 samples have higher photocatalytic properties due to pure anatase phase formation. The Mg-doped TiO2 sample was synthesized at Vwater/Vethanol of 12.5:2.5, which has the highest bleaching rate of 99.5% for the rhodamine B dye during 80 min under visible light. Adding Mg2+-doped TiO2 into the phase-separated glaze is an essential factor for enhancing the self-cleaning capability. The glaze samples fired at 1180 °C achieved a water contact angle of 5.623° at room temperature and had high stain resistance (the blot floats as a whole after meeting the water)

Enhanced enzymatic hydrolysis of poplar cellulosic residue fractionated by a magnetic carbon-based solid-acid catalyst in the gamma-valerolactone-water system

The conventional pretreatment method of poplar comprises multiple steps, including different procedures for fractionating hemicellulose and lignin separately. In our study, hemicellulose and lignin were removed simultaneously by a one-step method. In the gamma-valerolactone (GVL)-water environment, the cellulose retention, hemicellulose removal, and lignin removal rates of 84.94%, 89.08%, and 72.28%, respectively, were achieved over a magnetic carbon-based solid acid (MMCSA) catalyst, under best conditions (160 degrees C, 30 min, 2 g of poplar, 2 g of MMCSA, 35 mL of GVL, and 15 mL of water). The pretreatment of fresh poplar in the reused MMCSA-GVL-water environment showed similar fractionation results as the first time. Scanning electron microscopy characterization of the cellulosic residue revealed the presence of noticeable structural fragmentation. Brunauer-Emmett-Teller characterization showed that the total pore volume of the residue was 2.13 times that of the raw material. The above features of the residue confirmed the high enzymatic hydrolysis potential of the pretreated residue. The enzymatic hydrolysis efficiency of the poplar residue was 67% at a cellulase loading of 20 FPU/g cellulose in dry matter, and it increased to 77.02% at 40 FPU/g cellulose in dry matter. Interestingly, the addition of Tween 80 did not improve the enzymatic hydrolysis efficiency at high cellulase loadings (30 and 40 FPU/g cellulose in dry matter) compared to the case at low cellulase loadings. The relative mechanisms were also analyzed. In this study, a one-step pretreatment method comprising the MMCSA-GVL system for the catalytic depolymerization of poplar wood was developed. The system was verified to be very effective for the subsequent enzymatic hydrolysis of the residues