Surface Of Microcrystalline Cellulose Research Articles

Environmentally Benign High‐Performance Composites‐Based Hybrid Microcrystalline Cellulose/Graphene Oxide

ABSTRACTA novel silane functionalization prepared by a solution mixing approach of epoxy composites filled with eco‐friendly reinforcement filler, that is, graphene oxide (GO) and microcrystalline cellulose (MCC). The developed composites were subjected to comprehensive analysis using various characterization techniques, encompassing mechanical testing, water absorption analysis, thermal stability assessment, and scanning electron microscopy (SEM). The tensile strength and Young's Modulus of the epoxy composite filled with 1.0 wt.% of GO (EGO1.0) demonstrated the highest value viz. 29.83 MPa and 1991.71 MPa, respectively, when compared to neat epoxy composite (E0). Meanwhile, the thermal gravimetry analysis (TGA) studies, particularly char yield, highlight improvements in the thermal stability of the EGO2.5 composite, that is, 23.39% representing a 33.73% increment compared to the E0 composite. The synergistic effect of hybrid filler, achieved by a combination of micro and nanoparticle fillers within an epoxy matrix, was investigated as a virtuous alternative to the conventional epoxy nanocomposites. A uniform dispersion of GO on the MCC surface leads to significant improvements in the mechanical properties and thermal stability of the epoxy‐reinforced composite. The maximum tensile strength, Young's Modulus, and break strain of 39.77 MPa, 2591.27 MPa, and 2.90%, respectively, were observed for the modified EGO1.0MCC1.5 composite. The synergistic effect of hybrid eco‐friendly reinforcement fillers (GO/MCC) and a strong interfacial adhesion between the matrix and filler reduces the formation of defects, thereby resulting in good stress transfer from matrix to fillers.

Shopping around: Comparing Cd(II) sorption performance of disparate functional groups-modified microcrystalline cellulose composites

The structure-function relationship of functionalized microcrystalline cellulose (MCC) composites as adsorbents remains unclear. Herein, the orange peel-derived MCC (i.e., OP-OH-H-25) was treated by different functional agents to prepare adsorbents for cadmium (Cd(II)) removal. Mercaptoacetic acid and orthophosphoric acid did not apparently impact MCC's surface site types and contents. Alternatively, they efficiently purified OP-OH-H-25 and generated OP-OH-SH and OP-OH-P samples with increased cellulose amounts. In contrast, the glycine modification produced OP-OH-NH2 with fewer sulfhydryl/carboxyl functional groups and more amide/amino sites. The pH-dependent Cd(II) removal trends by the MCC-related materials showed three successive stages with disparate sorption modes. The Cd(II) sorption kinetics processes on OP-OH-SH, OP-OH-P, and OP-OH-NH2 reached equilibrium after 0.25 h, faster than 0.5 h on OP-OH-H-25. The maximum Cd(II) sorption capacities of MCC-related adsorbents were OP-OH-P (151.81 mg/g) > OP-OH-SH (150.80 mg/g) > OP-OH-H-25 (124.90 mg/g) > > OP-OH-NH2 (55.23 mg/g). OP-OH-P exhibited the strongest Cd(II) sorption ability under the interference of mixed aquatic components. The intrinsic Cd(II) sorption mechanisms were identified as inner-sphere complexation and cation-π bond interaction. Overall, the select priority of modifying agents is orthophosphoric acid > mercaptoacetic acid > > glycine when preparing functionalized MCC adsorbents for purifying Cd(II)-polluted water systems.

Enhanced dissolution rates of glibenclamide through solid dispersions on microcrystalline cellulose and mannitol, combined with phosphatidylcholine

Objective This study aimed to investigate the impact of physical solid dispersions of spray-dried glibenclamide (SG) on the surface of microcrystalline cellulose (MC) and mannitol (M) surfaces, as well as their combination with phosphatidylcholine (P), on enhancing the dissolution rate of glibenclamide (G). Methods Solid dispersions were prepared using varying proportions of 1:1, 1:4, and 1:10 for SG on the surface of MC (SGA) and M (SGM), and then combined with P, in a proportion of 1:4:0.02 using spray drying. The particle size, specific surface area, scanning electron microscopy (SEM), X-ray diffraction (XRD), and dissolution rate of SGA and SGM were characterized. Results SEM analysis revealed successful adhesion of SG onto the surface of the carrier surfaces. XRD showed reduced crystalline characteristic peaks for SGA, while SGM exhibited a sharp peaks pattern. Both SGA and SGM demonstrated higher dissolution rates compared to SG and G alone. Furthermore, the dissolution rates of the solid dispersions of SG, MC and P (SGAP), and SG, M, and P (SGMP) were sequentially higher than that of SGA and SGM. Conclusions The study suggests that physical solid dispersions of SG on MC and M, along with their combination with P, can effectively enhance the dissolution rate of G. These findings may be valuable in developing of oral solid drug dosage forms utilizing SGA, SGM, SGAP, and SGMP.

Grafting 3-trimethoxysilylpropyl)diethylenetriamine on microcrystalline cellulose for the adsorption of dyes: Experimental and modeling studies

Textile dyes are one of the most commonly found pollutants in water, and it is necessary to remove them before textile industry effluents are released into the environment. In this study, cellulose-based adsorbents were prepared by grafting N1-(3-trimethoxysilylpropyl)-diethylenetriamine (TMSPDETA) on microcrystalline cellulose surface for the adsorption of reactive dyes from aqueous solution. Characterization of the produced adsorbents [Cel@TMSPDETA10; composite of cellulose + TMSPDETA (10% weight)] and the experimental and modeling studies were thoroughly investigated. Based on ΔBIC analysis (Bayesian Information Criterion), the fractal-like pseudo-first-order model (FPFO) was the model with the highest degree of adequacy to describe the kinetic behavior for RR-35 (Reactive Red 35) and RG-19 (Reactive Green 19) dye adsorption on Cel@TMSPDETA10. It was observed that the values of t0.95 (time necessary to attain 95% saturation) of RG-19 dye were 1.81 times slower than those of RR-35. This difference in times to attain 95% saturation of RG-19 with RR-35 could be assigned to the larger size of the RG-19 molecule. Based on the ΔBIC values, the Liu isotherm was better fitted to the experimental data. At 30 °C, the highest Qmax (Liu model) value was 197.0 mg g−1 for RR-35 dye. For RG-19, the highest value of Qmax (Liu model) was 210.5 mg g−1 at 45 °C. Alternatively, a statistical physics model that represents the general case of the Langmuir model was adopted to provide new insights into the adsorption mechanisms of RR-35 and RG-19 dyes on the adsorbents. Interestingly, this new approach showed that RR- 35 was adsorbed via a partial aggregation process, contrary to the RG-19 dyes.

Ferromagnetic Enhancement of Microcrystalline Cellulose via Chemical Reduction Method

Iron oxide nanoparticles (NPs) have potential in biological, biomedical, and environmental applications because of their magnetic susceptibility, stability, and biocompatibility characteristics. However, it also has limitations, such as the aggregation of magnetic NP. Thus, the outer surface of the particles should be modified by coating materials. This paper focused on synthesizing iron oxide by chemical reduction method and coating it with Fe(III) nitrate, PVP, and hydrazine. The coating solution at two different concentrations was prepared to determine effective and economical usage conditions. The effect of coating iron oxide with microcrystalline cellulose (MCC) was conducted at different concentrations of iron oxide on the nanomaterials with respect to morphological, thermal, and magnetic susceptibility. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated good morphology images of FeNp-MCC. Energy dispersive X-ray (EDX) spectra reveal the presence of carbon, oxygen, and iron in the synthesized microparticles.TGA analysis showed iron material was succesfully formed into the surface of microcrystalline cellulose. Lastly,the magnetism results proved that cellulose is strongly interacting with magnetite nanoparticles.

Fabricating the multibranch carboxyl-modified cellulose for hemorrhage control

Excessive bleeding is associated with a high mortality risk. In this study, citric acid and ascorbic acid were sequentially modified on the surface of microcrystalline cellulose (MCAA) to increase its carboxyl content, and their potential as hemostatic materials was investigated. The MCAA exhibited a carboxylic group content of 9.52 %, higher than that of citric acid grafted microcrystalline cellulose (MCA) at 4.6 %. Carboxyl functionalization of microcrystalline cellulose surfaces not only plays a fundamental role in the structure of composite materials but also aids in the absorption of plasma and stimulation of platelets. Fourier -transform infrared (FT-IR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) spectra confirmed that carboxyl groups were successfully introduced onto the cellulose surface. Physical properties tests indicated that the MCAA possessed higher thermal stability (Tmax = 472.2 °C) compared to microcrystalline cellulose (MCC). Additionally, in vitro hemocompatibility, cytotoxicity and hemostatic property results demonstrated that MCAA displayed good biocompatibility (hemolysis ratio <1 %), optimal cell compatibility (cell viability exceeded 100 % after 72 h incubation), and impressive hemostatic effect (BCIMCAA = 31.3 %). Based on these findings, the hemostatic effect of covering a wound with MCAA was assessed, revealing enhanced hemostatic properties using MCAA in tail-amputation and liver-injury hemorrhage models. Furthermore, exploration into hemostatic mechanisms revealed that MCAA can significantly accelerate coagulation through rapid platelet aggregation and activation of the clotting cascade. Notably, MCAA showed remarkable biocompatibility and induced minimal skin irritation. In conclusion, the results affirmed that MCAA is a safe and potentially effective hemostatic agent for hemorrhage control.

Performance of thermally conductive NR composites reinforced with stearic acid‐modified microcrystalline cellulose: A combined experimental and molecular dynamic simulation study

AbstractWith the increasing environmental requirements for improving products and materials using renewable and sustainable resources, cellulose has been seen as one of the most attractive and promising alternatives to traditional inorganic fillers. We developed a new modification method to improve the interface compatibility between natural rubber and sisal cellulose, to improve the mechanical and thermal conductivity properties of rubber composite. Microcrystalline cellulose (MCC) was extracted from sisal cellulose and then the hydrophobic cellulose (SA‐MCC) was prepared by grafting stearic acid on the surface of MCC. MCC and SA‐MCC were added to the thermal conductivity composite material composed of natural rubber and boron nitride. The results showed that the thermal conductivity and tensile properties of the natural rubber composites increased by 17.3% and 20%, respectively, under the addition of 1.8 wt% SA‐MCC. Furthermore, the interfacial interaction between the components in the composite was studied by molecular dynamics simulation. The solubility parameters, free volume fraction, and molecular binding energy were calculated to verify the effectiveness of the modification. This work is expected to provide a theoretical basis for the design and preparation of high‐performance natural rubber composite materials.Highlights Cellulose microcrystals were successfully extracted from sisal fiber and modified. Through the combination of boron nitride and the modified cellulose microcrystals, the thermal conductivity and tensile properties of thermal rubber were successfully improved synchronously. A reasonable molecular simulation model was established to analysis the strengthening mechanism from the microscopic point of view. The molecular simulation conclusions on interface enhancement are in good agreement with the experimental properties.

Removal of Aqueous Pb2+ on Partially esterified Cellulose Obtained by Almond Shell Dissolution Using Deep Eutectic Solvent

Microcrystalline cellulose (MCC) was isolated from the almond shell after its pretreatment with an acidic deep eutectic solvent (DES) of choline chloride/oxalic acid under microwave irradiation. The Fourier transform infrared spectroscopy analysis showed that the spectrum of the isolated (MCC) includes an additional peak at 1747.0 cm−1 which refers to the (C=O) esters and carboxylic peak. This indicates that the MCC surface has undergone simultaneous partial esterification during the isolation process. Owing to its favorable structural and morphological properties, the isolated MCC was successfully employed for the adsorption of aqueous Pb2+ ions with (50 mg/g) efficiency using a 3.0 g/L adsorbent dose at pH (6.5) and 20 °C. The adsorption was spontaneous near the ambient temperature, pH dependent, and exothermic. The Coulomb forces are the foremost adsorption driving force. The reusing of the spent DES and adsorbent for four successive rounds, affirmed their applicability on industrial scales.

Preparation of manganese-oxides-coated magnetic microcrystalline cellulose via KMnO4 modification: Improving the counts of the acid groups and adsorption efficiency for Pb(II)

Herein, the manganese-oxides-coated magnetic microcrystalline cellulose (MnOx@Fe3O4@MCC) was prepared by coprecipitation and subsequently modified with KMnO4 solution at room temperature, which was in turn applied for the removal of Pb(II) from wastewater. The adsorption properties of Pb(II) on MnOx@Fe3O4@MCC were investigated. The kinetics and isothermal data of Pb(II) were described well by the Pseudo-second-order model and the Langmuir isotherm model, respectively. At pH = 5, 318 K, the Langmuir maximum Pb(II) adsorption capacity of MnOx@Fe3O4@MCC was 446.43 mg/g, which is higher than many documented bio-based adsorbents. The results of Fourier transform infra-red and X-ray photoelectron spectroscopy indicated that the adsorption mechanisms for Pb(II) mainly involved surface complexation, ion exchange, electrostatic interaction and precipitation. Interestingly, the increased amount of carboxyl group on the surface of microcrystalline cellulose modified by KMnO4 was one of the important reasons for the high Pb(II) adsorption performance of MnOx@Fe3O4@MCC. Furthermore, MnOx@Fe3O4@MCC exhibited excellent activity (70.6 %) after five consecutive regeneration cycles, indicating its high stability and reusability. Endorsing to the cost-effectiveness, environmentally friendliness, and reusable nature, MnOx@Fe3O4@MCC can be counted as a great alternative contender for the remediation of Pb(II) from industrial wastewater.

Heterogeneous Epoxidation of Microcrystalline Cellulose and the Toughening Effect toward Epoxy Resin

Microcrystalline cellulose (MCC) is regarded as a potential filler in the fabrication of epoxy composites. However, MCC’s hydrophilic nature and strong hydrogen bonds caused by abundant surface hydroxyl groups greatly weaken its compatibility with the epoxy resin. In addition, it remains a challenge to efficiently and heterogeneously modify MCC surface hydroxyl groups. In this work, MCC was epoxidized heterogeneously with a phase-transfer catalyst. Results indicated that 4.48% (by mass) or 58.15% (by coverage) of the hydroxyl groups on MCC was modified. The dispersibility of epoxidized MCC (EP-MCC) in the epoxy resin was significantly improved. At the same time, EP-MCC showed the ability to interact with the epoxy network covalently, improving the interface interactions, indicating the simultaneous enhancement of the modulus and the toughness. As a result, this heterogenous epoxidation method showed high efficiency in reducing the surface hydroxyl content of MCC, endowing it with a bright future in industrial applications of epoxy composites.

Poly(dopamine)-modified microcrystalline cellulose,a green reinforcing filler for natural rubber latex with high performance

ABSTRACT The presence of a large number of reactive -OH groups on the surface of the microcrystalline cellulose (MCC) causes the MCC to easily agglomerate together due to hydrogen bonding, reducing the dispersion of the MCC in the NRL matrix. At the same time, the poor interfacial compatibility between the hydrophilic MCC and the hydrophobic NRL substrate does not achieve a good reinforcement effect, thus limiting to a certain extent the application of MCC in rubber substrates. The surface modification of MCC by poly(dopamine) (PDA) for improving the performance of rubber composites and broadening the application of MCC in NRL matrix, and improving the dispersibility and interfacial interaction of nanofillers in natural rubber latex (NRL) composites was studied. We report the effects of the MCC/PDA ratios on the vulcanization characteristics, the Payne effect, and the mechanical properties of the developed composites. These facts exhibit that not only the processing properties but also the mechanical performance of NRL/MCC/PDA are better than those of the NRL/MCC composites. This study reports an efficient approach to improving the interfacial interaction of the nanocomposite. Based on this, as a green reinforcing filler, MCC modified with PDA shows great potential in reinforcing NRL composites. Furthermore, a simple dip-coating method was used to modify the surface of MCC with dopamine. FTIR, TGA, and XRD confirmed the interaction between PDA and MCC.

Iridium-Functionalized Cellulose Microcrystals as a Novel Luminescent Biomaterial for Biocomposites

Microcrystalline cellulose (MCC) is an emerging material with outstanding properties in many scientific and industrial fields, in particular as an additive in composite materials. Its surface modification allows for the fine-tuning of its properties and the exploitation of these materials in a plethora of applications. In this paper, we present the covalent linkage of a luminescent Ir-complex onto the surface of MCC, representing the first incorporation of an organometallic luminescent probe in this biomaterial. This goal has been achieved with an easy and sustainable procedure, which employs a Bronsted-acid ionic liquid as a catalyst for the esterification reaction of -OH cellulose surface groups. The obtained luminescent cellulose microcrystals display high and stable emissions with the incorporation of only a small amount of iridium (III). Incorporation of MCC-Ir in dry and wet matrices, such as films and gels, has been also demonstrated, showing the maintenance of the luminescent properties even in possible final manufacturers.

Rapid Solvent-Free Microcrystalline Cellulose Melt Functionalization withl-Lactide for the Fabrication of Green Poly(lactic acid) Biocomposites

A green approach is proposed to achieve a rapid surface functionalization of microcrystalline cellulose (MCC) in 30 min by a solvent-free "grafting from" reaction of l-lactide through compression molding without the need for an inert atmosphere. A sufficient hydrophobization of the MCC surface is achieved with an amount of grafted poly(l-lactic acid) (PLLA) oligomers of 7 wt % with respect to MCC. The obtained MCC-g-PLLA is subsequently melt-compounded with poly(lactic acid) (PLA) through extrusion and injection molding. As a result of higher compatibility and interfacial adhesion of the functionalized filler with PLA, PLA/MCC-g-PLLA biocomposites with a cellulose content ranging from 4 to 20 wt % exhibit an enhancement in important physicochemical properties (i.e., water vapor barrier, crystallinity, stiffness) compared to both pure PLA and formulations containing an equal or higher amount of nonfunctionalized MCC. At the same time, the materials retain the mechanical strength and resistance to thermal degradation of PLA. The physicochemical characteristics, excellent biocompatibility, and biodegradability of PLA and cellulose and the simplicity, rapidity, and cost-effectiveness of the grafting process render these biocomposites suitable for several applications within the plastics domain including packaging, agriculture, automotive, consumer goods, and household appliances.

The influence of ionic liquid concentration on microcrystalline cellulose modification

Ethanolic ionic liquid (IL) solutions, containing different 1-n-butyl-3-methylimidazolium chloride (C4MImCl) concentrations were used to modify the surface of commercial microcrystalline cellulose (MCC). The chosen ratios were: 4, 8, 16, and 32 wt.% of IL, in relation to the MCC mass. These treatments with IL did not affect the MCC morphology. FTIR analysis showed the characteristic bands of C4MImCl when the IL concentration was higher than 4 wt.%. XRD diffractograms show that the crystals may have been disrupted for IL concentrations above 4 wt.%. 1H NMR confirmed the formation of strong hydrogen bonds between C4MImCl and MCC, especially for MCC treated with 4 wt.% of IL. The functionalization using IL, regardless of the content, showed two DTG peaks, without altering the MCC Arrhenius’ parameters and degradation mechanisms. 4 wt.% of C4MImCl proved to be suitable for the MCC surface modification, improving thermal stability without detrimental effects on MCC morphology.

Enhancing the mechanical performance of surface-modified microcrystalline cellulose reinforced high-density polyethylene composites

The microcrystalline cellulose (MCC) was successfully modified with a poly(ethylene-co-glycidyl methacrylate) copolymer (PEGMA) to be constructed the PEGMA anchored MCC (PEGMA-a-MCC). The chemical modification of the pristine MCC surface was confirmed by X-ray photoelectron spectroscopy (XPS) analysis. And then, the pristine MCC and PEGMA-a-MCC were successfully incorporated into the high-density polyethylene (HDPE) matrix by typical melt-mixing technique. When applied the PEGMA-a-MCC, interfacial adhesion performance between the cellulosic filler and HDPE matrix showed better and stronger than the pristine MCC. From the results of thermal behaviors and mechanical properties of the composites, it was possible to achieve enhanced their mechanical properties without change of thermal characteristics of HDPE matrix.

Physico-chemical properties of flax microcrystalline cellulose

Mechanical activation is a simple, fast, cost-effective green technology that has been used for the upgrading and modification of microcrystalline cellulose (MCC). However, there is no information on the effect of short-term grinding on its physicochemical properties, as it is widely used for obtaining MCC powder or smaller particle with a size below 50 µm. Thus, the aim of our work was the investigation of physico-chemical properties of the flax unground and short-term ground MCC. In that study MCC was derived from air-dry flax in the medium ‘‘acetic acid–hydrogen peroxide–water’’ in the presence of 2 wt% sulfuric acid catalyst and then in the dry state it was ground in the laboratory mill for 1, 2 and 5 min. The morphology and composition of mechanically unground and ground MCC samples were analysed by different methods: XRD, XRF, FTIR-ATR, AFM, TGA and DSC. According to the XRD patterns of MCC samples, mechanical activation did not change the crystalline form of cellulose, but obviously, it destroyed the crystal structure of ground MCC, resulting in the increase of amorphization and the decrease of crystallinity index (from 86.2 to 78.2%). The FT-IR spectra also showed that the band corresponded to symmetric CH2 bendings at 1435–1429 cm−1, known as the crystallinity band, decreased with MCC samples grinding. AFM indicated that relief of the surface of original MCC changed by mechanical grinding (from the relief with large and small aggregates to the relief consisted of long-chain cellulose molecules parallel layers).

Improvement in the Performance of the Polylactic Acid Composites by Using Deep Eutectic Solvent Treated Pulp Fiber

As the most favorable alternative to petroleum-based polymers, polylactic acid (PLA) which is the most promising degradable polymer has attracted increasing attention. However, the addition of cellulose to improve its strength often results in a reduction in its toughness. In this work, microscale cellulose is first prepared from pulp fibers by using a deep eutectic solvent, and then is used as the reinforcement of PLA. A microcrystalline cellulose (MCC)/PLA sheet with uniform texture is obtained by the solution mixing, melt blending, hot-pressing and cold-pressing process. The effects of MCC on the crystallization, thermal stability and mechanical properties of the PLA matrix were studied. Upon the addition of 1% cellulose fiber, the tensile strength of MCC/PLA composite sheet increased by 27%, and the elongation at break did not shown an evident decrease. The strength enhancement mechanism was elucidated using scanning electron microscopy, differential scanning calorimetry, and dynamic thermomechanical analysis. The energy dissipation during the deformation process and the compatibility of AMCC and rougher surface of MCC play important role in the strength enhancement. Additionally, UV spectroscopy showed that the composite material absorbed some ultraviolet light. Our results show that the combined use of a deep eutectic solvent and solution mixing is an effective approach for improving the strength of PLA while maintaining its toughness.

Stimuli-Responsive Biomass Cellulose Particles Being Able to Reversibly Self-Assemble at Fluid Interface.

Stimuli-responsive surface-active microcrystalline cellulose (MCC) particles are obtained by interaction with conventional cationic surfactants such as cetyltrimethylammonium bromide (CTAB) in aqueous media, where MCC are in situ hydrophobized by adsorption of the cationic surfactant in water via electrostatic interaction and with the in situ hydrophobization removed by adding an equimolar amount of an anionic surfactant such as sodium dodecyl sulfate (SDS). The trigger is that the electrostatic interaction between the oppositely charged ionic surfactants is stronger than that between the cationic surfactant and the negative charges on particle surfaces, or the anionic surfactant prefers to form ion pairs with the cationic surfactants and thus making them desorbed from surface of MCC. Reversible O/W Pickering emulsions can then be obtained by using the MCC in combination with trace amount of a cationic surfactant and an anionic surfactant, and the anionic surfactant with a longer alkyl chain is more efficient for demulsification. With excellent biocompatibility, biodegradability, and renewability, as well as low toxicity, the biomass cellulose particles that can be made stimuli-responsive and able to reversibly self-assemble at fluid interface become ideal biocompatible particulate materials with extensive applications involving emulsions and foams.

Effects of microcrystalline cellulose surface modification on the mechanical and thermal properties of polylactic acid composite films

ABSTRACT Microcrystalline cellulose (MCC), extracted from distiller’s grains by nitric acid-ethanol hydrolysis, was prepared for PLA composite films by solution casting. MCC based on the optimum comparison was characterised by particle size analysis and scanning electron microscopy. The results show that the ultrasound combined sulphonation treatment was remarkable for the surface structure of MCC, compared with that modified by sulphonation and ultrasound methods. The MCC/PLA composite films were analysed using Fourier-transform infrared spectroscopy (FT-IR), mechanical properties and thermal resistance. The results show that the properties and performance of MCC/PLA composite film using ultrasound combined sulphonation treatment are obviously better than those of modified films by other methods. For the modified MCC/PLA composite film by sulphonation and ultrasound methods, the FT-IR analysis carried out a large number of hydroxyl groups that are hydrolysed, the tensile strength upped to 505.24 MPa and the thermal-decomposed temperature increased to 320°C from 260°C. The modified MCC would be a beneficial filling material for the properties of PLA composites.

A lytic polysaccharide monooxygenase from Myceliophthora thermophila C1 and its characterization in cleavage of glycosidic chain of cellulose

Lytic polysaccharide monooxygenase (LPMO), a kind of copper-dependent oxidases, has been widely used for the efficient enzymatic hydrolysis of lignocellulosic biomass. In this study, a gene encoding the LPMO from Myceliophthora thermophila C1 (MtC1LPMO) was expressed in Pichia pastoris GS115. A high secretion level of recombinant MtC1LPMO protein was obtained in the culture medium using its native signal peptide. Consequently, MtC1LPMO with a purity of more than 95 % and yield of 46 mg/L was obtained. The optimal enzyme activity was observed at pH 7.5 and 85 °C, and the enzyme displayed remarkable thermostability at 40–60 °C. MtC1LPMO exhibited a synergistic activity with cellulase in the degradation of microcrystalline cellulose, and the reducing sugar content increased by 29 % compared to cellulase alone. Additionally, the results of scanning electron microscopy revealed that MtC1LPMO would cleave the glycosidic chain, leading to subsequent disruption to the surface of microcrystalline cellulose. Finally, the interaction model of MtC1LPMO and cellohexaose was explored using molecular docking simulations, which showed that the residues H1, H68, Y153, H142, Y67, V143, S146, G149, Q151 and P69 of MtC1LPMO played an important role in interacting with cellohexaose.