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Pickering emulsion stabilized by lignin particles has many advantages such as high flexibility, natural non-toxicity, anti-oxidation, and anti-ultraviolet. In order to promote the application of industrial lignin in the field of Pickering emulsions, this study has done comparatively systematic and basic research on Pickering emulsions stabilized by lignin particles. The emulsification effects of lignin particles on cyclohexane and n-decanol which have opposite polarity were compared firstly under different oil-water ratios. It was found that stable emulsions formed when the three-phase contact angle of oil/water/lignin was closer to 90°. The weakly polar cyclohexane could be well-emulsified by lignin particles, while the strong polar n-decanol could not. Cyclohexane was used as the oil phase to discuss the emulsification ability of lignin particles under different concentrations or with different particle sizes. The results show increasing the concentration of lignin particles or reducing the particle size can improve the emulsification performance. [ABSTRACT FROM AUTHOR]

Organic pollutants pose a serious threat to water environment, thus it is essential to develop high-performance adsorbent to remove them from wastewater. Herein, nitrogen-doped magnetic porous carbon (M-PLAC) with three-dimensional porous structure was synthesized from lignin to adsorb methylene blue (MB) and tetracycline (TC) in wastewater. The calculated equilibrium adsorption amount by M-PLAC for MB and TC was 645.52 and 1306.00 mg/g, respectively. The adsorption of MB and TC on M-PLAC conformed to the pseudo-second-order kinetic model. The removal of MB by M-PLAC showed fast and efficient characteristics and exhibited high selectivity for TC in a binary system. In addition, M-PLAC was suitable for a variety of complex water environments and had good regeneration performance, demonstrating potential advantages in practical wastewater treatment. The organic pollutant adsorption by M-PLAC was attributed to electrostatic interaction, hole filling effect, hydrogen bonding, and the π-π interaction. [ABSTRACT FROM AUTHOR]

Artificial muscle materials promise incredible applications in actuators, robotics and medical apparatus, yet the ability to mimic the full characteristics of skeletal muscles into synthetic materials remains a huge challenge. Herein, inspired by the dynamic sacrificial bonds in biomaterials and the self-strengthening of skeletal muscles by physical exercise, high performance artificial muscle material is prepared by rearrangement of sacrificial coordination bonds in the polyolefin elastomer via a repetitive mechanical training process. Biomass lignin is incorporated as a green reinforcer for the construction of interfacial coordination bonds. The prepared artificial muscle material exhibits high actuation strain (>40%), high actuation stress (1.5 MPa) which can lift more than 10,000 times its own weight with 30% strain, characteristics of excellent self-strengthening by mechanical training, strain-adaptive stiffening, and heat/electric programmable actuation performance. In this work, we show a facile strategy for the fabrication of intelligent materials using easily available raw materials. Artificial muscles have a wide range of applications yet truly mimetic designs remain a challenge. Here, the authors use dynamic sacrificial bonds which are rearranged via a mechanical training process to optimise the characteristics of self-strengthening, strain-adaptive stiffening and actuation. [ABSTRACT FROM AUTHOR]

Pickering emulsion stabilized by lignin/sodium dodecyl sulfate composite nanoparticles (LSNP) was used as template to prepare the avermectin @ lignin/polyurea composite microcapsules (AVM@LPMC) through ion cross-linking and interfacial polymerization. The inner wall of the microcapsules is a firm and compact polyurea layer, and the outer wall is a loose lignin layer. The effects of stirring speed, dosage of sodium dodecyl sulfate (SDS), and pH value in aqueous phase on the formation of microcapsules were systematically studied. The results showed that the optimal stirring speed was 200 rpm, and the optimal dosage ratio in water phase was HCl (mmol):SDS (mmol):lignin AL (g) = 0.375:1.25:1 in fixed oil-water ratio (1:9) and oil phase composition. In this way, the encapsulation efficiency of microcapsules could reach up to 85.4%, while it would slightly decrease with the increase of lignin content in the wall materials. The polyurea layer played a key role in supporting the spherical structure of the capsule wall and delaying the release of avermectin, while the loose lignin layer contributed less to the slow release performance of microcapsule. By changing the amount of lignin, the polyurea-layer thickness could be regulated to adjust the release rate of microcapsule. Remarkably, a small amount of lignin introduced in the wall material could significantly improve the anti-photolysis performance of avermectin in microcapsules. [ABSTRACT FROM AUTHOR]

Using a co-precipitation approach, we introduce Co into LiNi0.5Mn1.5O4 to prepare a series of Co-doped cathode materials in which the Co substitutes partial Ni and Mn. We then systematically study the effects of Co doping at these various sites. The structural and electrochemical properties are investigated by means of X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller analysis, galvanostatic charge–discharge tests, and electrochemical impedance spectroscopy. The Co-doped samples experience a slight capacity loss, but their cycling stability and rate properties are significantly improved. When Ni and Mn are simultaneously substituted, the capacities at 0.1 C and 2.0 C of a battery using this doped material as the cathode stay at 99.7% and 96.8%, respectively, after 80 cycles, which is much better than the results for a battery with undoped material as the cathode. [ABSTRACT FROM AUTHOR]

Highly recyclable pH-responsive lignin-polyethylene glycol (L-PEG) was synthesized to achieve enhanced lignocellulosic hydrolysis and recycling cellulase. The performance of L-PEG could be easily regulated by adjusting the molecular weight and the amount of PEG. The large molecular weight facilitated L-PEG to reduce the invalid adsorption of cellulase on lignin during hydrolysis and enhance its flocculation effect at around pH 3.0. L-PEG1000-40 obtained by adding 40 wt% (based on lignin) PEG1000 could effectively enhance the enzymatic hydrolysis of lignocelluloses and recover most of cellulase after hydrolysis through simply adjusting the pH of hydrolysate. During eucalyptus hydrolysis, using L-PEG1000-40 to recycle cellulase could not only save 40% cellulase, but also increase the glucose yield by 121%. Due to the low synthesis cost of L-PEG and the simple and convenient recovery operation, this new method is beneficial to the improvement of lignocellulosic saccharification process and the high-value utilization of lignin. [ABSTRACT FROM AUTHOR]

A linear pH-responsive zwitterionic copolymer P(MDB) was synthesized from functional monomers methacrylic acid, 2-(dimethylamino) ethyl methacrylate (DMA) and benzyl methacrylate (BMA) through free radical polymerization to recover cellulases and enhance the enzymatic hydrolysis. The hydrophobicity and molecular weight of the copolymer was controlled by the feed ratio of monomers and the mass ratio of initiator to monomers, respectively. UV-turbidity showed P(MDB) exhibited sensitive pH-responsiveness with dissolution–precipitation ΔpH about 1 pH unit. The precipitation pHφ of P(MDB) was 5.0–5.5 and over 90% of P(MDB) could precipitate in the vicinity of its isoelectric point. Increasing the hydrophobicity or molecular weight of P(MDB) could improve its pH sensitivity and precipitation rate. P(MDB) could enhance the enzymatic hydrolysis of dilute acid pretreated Eucalyptus by 10–25%. P(MDB) could recover the free cellulases in enzymatic hydrolysate by co-precipitation. SDS-PAGE analysis showed that P(MDB) could recover 100% β-glucosidase (β-GL) and the recovery rates of cellobiohydrolase (CBH) and endoglucanase (EG) increased as the hydrophobicity and molecular weight of P(MDB) increased. The mechanism was proposed that hydrophobic affiliation was the main binding force of P(MDB) to cellulases. Increasing the hydrophobicity and molecular weight of copolymer could increase its binding force and the number of binding sites to cellulases thus the overall cellulase recovery performance was improved. [ABSTRACT FROM AUTHOR]

Sulfonation degree is an important structural parameter of lignosulfonates which affect their water solubility, surface activity, and dispersing performance. Presently, the methods for determining sulfonation degree include elemental analysis and potentiometric titration; they have some shortcomings such as complex purification process, high equipment requirements, and time-consuming. Hence, a simple and rapid method to determine the sulfonation degree of lignosulfonates was proposed based on the electrostatic interaction between cationic surfactant (hexadecyl trimethyl ammonium bromide (CTAB)) and anionic lignosulfonates. CTAB was added and co-precipitated with lignosulfonates and then the ultraviolet absorbance of the supernatant was determined. The sulfonation degree of lignosulfonates was calculated according to the titration curve of the supernatant absorbance to the amount of CTAB. This method is applicable to lignosulfonates recovered from acid pulping as well as sulfonation products of alkali lignin. Because of the easy operation process and no purification process for lignosulfonates, this method was simple and rapid when compared to existing methods for sulfonation degree determination of lignosulfonates. [ABSTRACT FROM AUTHOR]

Effect of hydrogen bond breaker (urea) addition on the enzymatic hydrolysis of Avicel and eucalyptus pretreated by dilute acid (Eu-DA) was investigated. Urea enhanced the enzymatic hydrolysis of Eu-DA at 50 or 30 °C when the concentration of urea was below 60 g/L, while it inhibited the hydrolysis of Avicel. Low concentration urea (< 240 g/L) had little effect on the cellulase spatial structure and its activity. But it decreased cellulase binding to cellulose surface to inhibit the cellulose hydrolysis. Meanwhile, urea obviously prevented the adsorption of cellobiohydrolase I (CBHI) on the lignin in spite of little effect on the adsorption of β-glucosidase (BGL) and two endoglucanases (EGIII and EGV) on lignin. It was proposed that urea enhanced the enzymatic efficiency of Eu-DA by decreasing the cellulase adsorption on lignin surface. [ABSTRACT FROM AUTHOR]

Nonionic surfactants could effectively improve the enzymatic hydrolysis efficiency of lignocellulose, while small molecule anionic and cationic surfactants usually inhibited the enzymatic hydrolysis. The results showed that the anionic surfactant sodium dodecyl sulfate (SDS) could improve the enzymatic hydrolysis efficiency of Avicel at the concentration range of 0.1-1 mM, but it did inhibit enzymatic hydrolysis at higher concentration. Cationic surfactant cetyltrimethylammonium bromide (CTAB) was used to regulate the surface charge of SDS; thereby catanionic surfactant SDS-CTAB was formed. The effect of SDS-CTAB catanionic surfactant with varied molar ratios on the enzymatic hydrolysis of pure cellulose and corn stover at various enzymatic hydrolysis environments was investigated. SDS-CTAB could increase the enzymatic hydrolysis of corn stover at high solid loading from 33.3 to 42.4%. Using SDS-CTAB could reduce about 58% of the cellulase dosage to achieve 80% of the enzymatic hydrolysis of corn stover. SDS-CTAB catanionic surfactant could regulate the surface charge of cellulase in the hydrolyzate and reduce the non-productive adsorption of cellulase on the lignin, thereby improving the enzymatic hydrolysis efficiency of lignocellulose. [ABSTRACT FROM AUTHOR]

Effect of cationic surfactants alkyltrimethylammonium bromide (CTAB) with varied alkyl chain lengths on the enzymatic hydrolysis of Avicel and the surface charge of cellulase was investigated. Enzymatic hydrolysis of Avicel increased linearly from 42.1 to 61.4 % with the increase of the concentration of cetyltrimethylammonium bromide (CTAB) logarithmically from 0.0001 to 0.01 mM, and reached a maximum value at the concentration of 0.01-0.03 mM. When the concentration was increased further, the cellulase solution became positively charged and the enzymatic hydrolysis of Avicel decreased rapidly. With the increasing alkyl chain length, CTAB provided more proton and neutralized the negative charge of cellulase more obviously. Therefore, the required concentration of CTAB could be less to enhance the enzymatic hydrolysis of Avicel. In addition, CTAB could enhance enzymatic hydrolysis efficiency of corncob at high solid content from 35.0 to 56.3 %; CTAB could reduce about 60 % of the cellulase loading in the enzymatic hydrolysis of corncob to obtain the same glucose yield. Effect of CTAB on the enzymatic hydrolysis of typical pretreated softwood and hardwood was also investigated. This study laid the foundation for using CTAB to recover cellulase, and provided the design direction for cellulase with higher activity and better stability by adjusting its hydrophilicity and chargeability. [ABSTRACT FROM AUTHOR]

A novel pretreatment process using NaOH/Urea solution at room temperature was developed to overcome recalcitrance of lignocellulose for efficient bioconversion of miscanthus. The process consists of mechanical size reduction, pretreatment with NaOH/Urea solution, and filtration. The results indicated that the substrate enzymatic digestibility (SED) of miscanthus pretreated with 8 wt% NaOH and 12 wt% urea at 21 C for 30 min was up to 71.99 % at low enzyme loading of 5 filter paper units (FPU)/g glucan after 72 h hydrolysis. NaOH/Urea pretreatment efficiently removed lignin and hemicellulose. And their removal rates increased with the increase of pretreatment temperature, NaOH dosage and urea dosage. With the increase of NaOH dosage, the chemical composition removal rate decreased in the following order: lignin, xylan, araban, galactan. Meanwhile, NaOH/Urea pretreatment could open up the fiber structure, decrease cellulose crystallinity index, and prevent lignin droplets depositing on cellulose. The optimal condition for the NaOH/Urea pretreatment regarding this study was 6 wt% NaOH/12 wt% urea and 21 °C. Approximately 70 % glucose yield was achieved upon this condition. [ABSTRACT FROM AUTHOR]

The effects of long-chain fatty alcohols (LFAs) on the enzymatic hydrolysis of crystalline cellulose by two commercial Trichoderma reesei cellulase cocktails (CTec2 and Celluclast 1.5L) were studied. It was found that n-butanol inhibited the enzymatic hydrolysis, but n-octanol, n-decanol and n-dodecanol had strong enhancement on enzymatic hydrolysis of crystalline cellulose in the buffer pH range from 4.0 to 6.0. LFAs can increase the hydrolysis efficiency of crystalline cellulose from 37 to 57 % at Celluclast 1.5L loading of ten filter paper units (FPU)/g glucan. LFAs have similar enhancement on the enzymatic hydrolysis of crystalline cellulose mixed with lignin or xylan. The enhancement of LFAs increased with the decrease of the crystallinity index. LFAs not only enhanced the high-solid enzymatic hydrolysis of lignocellulose, but also improved the rheological properties of high-solid lignocellulosic slurries by decreasing the yield stress and complex viscosity. Meanwhile, LFAs can improve the enzymatic hydrolysis of cellobiose to glucose, especially at low cellulase loading. [ABSTRACT FROM AUTHOR]

The effects of lignosulfonate (LS) on enzymatic saccharification of pure cellulose were studied. Four fractions of LS with different molecular weight (MW) prepared by ultrafiltration of a commercial LS were applied at different loadings to enzymatic hydrolysis of Whatman paper under different pH. Using LS fractions with low MW and high degree of sulfonation can enhance enzymatic cellulose saccharification despite LS can bind to cellulase nonproductively. The enhancing effect varies with LS properties, its loading, and hydrolysis pH. Inhibitive effect on cellulose saccharification was also observed using LS with large MW and low degree of sulfonation. The concept of 'LS-cellulase aggregate stabilized and enhanced cellulase binding' was proposed to explain the observed enhancement of cellulose saccharification. The concept was demonstrated by the linear correlation between the measured amount of bound cellulase and saccharification efficiency with and without LS of different MW in a range of pH. [ABSTRACT FROM AUTHOR]

This study revealed that cellulose enzymatic saccharification response curves of lignocellulosic substrates were very different from those of pure cellulosic substrates in terms of optimal pH and pH operating window. The maximal enzymatic cellulose saccharification of lignocellulosic substrates occurs at substrate suspension pH 5. 2- 6. 2, not between pH 4. 8 and 5. 0 as exclusively used in literature using T. reesi cellulase. Two commercial cellulase enzyme cocktails, Celluclast 1.5L and CTec2 both from Novozymes, were evaluated over a wide range of pH. The optimal ranges of measured suspension pH of 5.2-5.7 for Celluclast 1.5L and 5.5-6.2 for CTec2 were obtained using six lignocellulosic substrates produced by dilute acid, alkaline, and two sulfite pretreatments to overcome recalcitrance of lignocelluloses (SPORL) pretreatments using both a softwood and a hardwood. Furthermore, cellulose saccharification efficiency of a SPORL-pretreated lodgepole pine substrate showed a very steep increase between pH 4.7 and 5.2. Saccharification efficiency can be increased by 80 % at cellulase loading of 11.3 FPU/g glucan, i.e., from approximately 43 to 78 % simply by increasing the substrate suspension pH from 4.7 to 5.2 (buffer solution pH from 4.8 to 5.5) using Celluclast 1.5L, or by 70 % from approximately 51 to 87 % when substrate suspension pH is increased from 4.9 to 6.2 (buffer solution pH from 5.0 to 6.5) using CTec2. The enzymatic cellulose saccharification response to pH is correlated to the degree of substrate lignin sulfonation. The difference in pH-induced lignin surface charge, and therefore surface hydrophilicity and lignin-cellulase electrostatic interactions, among different substrates with different lignin content and structure is responsible for the reported different enhancements in lignocellulose saccharification at elevated pH. [ABSTRACT FROM AUTHOR]