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1.
Int J Biol Macromol ; 154: 981-988, 2020 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-32171838

RESUMO

As a natural fluorescent material, the fluorescent property and mechanism of lignin were elusive until now, which hindered the high value application of lignin fluorescence. Herein, we firstly probed the previous studies on lignin fluorescence and the results indicated that lignin microstructure was an important factor for its complex fluorescence property because of fluorophore interaction and aggregation behavior. Following the rules, lignin fluorescence was explored by analyzing its aggregation fluorescence behaviors and basic fluorescence properties based on the theory of traditional conjugated luminescence and aggregation-induced emission. It was demonstrated that intermicellar aggregation of loose lignin micelle made no substantial effect on lignin fluorescence, while intramicellar aggregation could induce the enhancement of lignin fluorescence before the micellar compactness exceeded a critical value. Combined with the physicochemical structures and fluorescence properties of lignin, aggregation-induced conjugation from phenylpropane units was believed as the main sources of the visible emission of lignin and different phenylpropane aggregates consequently formed the multi-fluorophore system in lignin micelle. Furthermore, lignin aggregation fluorescence behavior has great potential in its microstructure analysis and a case study of pH/ionic strength-induced solution behavior analysis was presented. This work provided a totally new prospective for lignin fluorescence.

2.
Int J Biol Macromol ; 151: 421-427, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32061696

RESUMO

In this work, the anionic and cationic lignin-based drug-loaded materials (SL/CTAB) with strong hydrophobicity were prepared by using Sodium Lignosulfonate (SL) via self-assembly. The obtained SL/CTAB was used as drug-loaded material and emulsifier to prepare avermectin nano-formulation, which can be automatically dispersed into nano drug-loaded nanospheres in water. The cold and hot storage experiments show that the physical and chemical stability of the nano-formulation is good. The nano-formulation exhibits controlled-release performance, and the cumulative release amounts range from 56.27% to 87.33% in 62 h. Meanwhile, the release rates slow down with increasing SL/CTAB dosage. After UV irradiation for 50 h, the retention rates of avermectin in the nano-formulation range from 46.67% to 63.41%, which is 2.18-2.96 times higher than commercial avermectin Emulsifiable Concentrate (EC). The experiment of simulated rainwater scour-resistance shows that the affinity of lignin-based nano-formulation to the Epipremnum aureum leaves is higher than EC formulation.

3.
Bioresour Technol ; 304: 122974, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32062498

RESUMO

Most additives that capable of enhancing enzymatic hydrolysis of lignocellulose are petroleum-based, which are not easy to recycle with poor biodegradability. In this work, highly recyclable and biodegradable sodium caseinate (SC) was used to enhance lignocellulosic hydrolysis with improved cellulase recyclability. When the pH decreased from 5.5 to 4.8, more than 96% SC could be precipitated from the solution and recovered. Adding SC increased enzymatic digestibility of dilute acid pretreated eucalyptus (Eu-DA) from 39.5% to 78.2% under Eu-DA loading of 10 wt% and pH = 5.5, and increase cellulase content in 72 h hydrolysate from only 15.2% of the original to 60.0%, which facilitated the recovery of cellulases through re-adsorption by fresh substrates. With multiple cycles of re-adsorption, application of SC not only increased the sugar yield of Eu-DA by 95.5%, but also reduced cellulase loading by 40%.


Assuntos
Celulase , Celulases , Caseínas , Hidrólise , Lignina
4.
Int J Biol Macromol ; 150: 371-379, 2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32007548

RESUMO

In this work, a novel lignin/titanium dioxide (QAL/TiO2) hybrid composite with regular microstructure and synergistically enhanced UV absorption properties was synthesized by a simple hydrothermal method using lignin and butyl titanate. The prepared QAL/TiO2 composite is hybrid structure in which lignin and TiO2 is uniformly embedded, and has strong chemical bond bonding force. The QAL/TiO2 hybrid composite particles were used for doping modification of waterborne polyurethane (WPU), which had good interfacial compatibility and dispersibility in WPU. The obtained WPU + QAL/TiO2 film shows excellent UV shielding performance and great mechanical properties, the tensile strength and elongation at break are significantly improved compared with pure WPU film. And it also has excellent anti-UV aging property, that the mechanical performance basically remains unchanged after 96 h of high power ultraviolet irradiation. This work not only provides a kind of lignin/TiO2 hybrid composite with neat structure, good dispersion and excellent optical properties, but also has great significance for the high-valued utilization of biomass resources.

5.
Artigo em Inglês | MEDLINE | ID: mdl-31950443

RESUMO

Horseradish peroxidase (HRP) has demonstrated high activity for the modification of lignin. In this paper, several lignin model compounds with different functional groups and linkages are selected to investigate the reactivity of HRP-catalyzed lignin modification. The phenolic groups of lignin model compounds are indispensable for the HRP-catalyzed modification process. The introduction of the sulfomethylated methyl group or methoxyl group could facilitate or inhibit the modification, respectively. The oxidative coupling activity of α-O-4 lignin model compounds is higher than that of ß-O-4 compounds. Meanwhile, the free energy obtained by density functional theory (DFT) is used to verify the results of the experimental study, and the order of preference for linkages is ß-5 > ß-ß > ß-O-4 in most cases. In addition, electron cloud density and steric hindrance of lignin model compounds have crucial effects on the oxidation and modification processes. Finally, the mechanism of HRP-catalyzed lignin modification is proposed.

6.
ChemSusChem ; 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31951671

RESUMO

Lignin-based nanomaterials fabricated by solution self-assembly in organic-aqueous solvent mixtures are among the most attractive biomass-derived products. To accurately control the structure, size, and properties of lignin-based nanomaterials, it is important to achieve fundamental understanding of its dissolution and aggregation mechanisms. In this work, atomic force microscopy (AFM) and molecular dynamics (MD) simulations are employed to explore the dissolution and aggregation behavior of enzymatic hydrolysis lignin (EHL) in different organic-aqueous solvent mixtures at molecular scale. EHL was found to dissolve well in appropriate organic-aqueous solvent mixtures, such as acetone-water mixture with a volume ratio of 7:3, whereas it aggregated in pure water, ethanol, acetone, and tetrahydrofuran. The interactions between the EHL-coated AFM probe and the substrate were 1.21±0.18 and 0.75±0.35 mN m-1 in water and acetone, respectively. In comparison, the interaction decreased to 0.15±0.08 mN m-1 in acetone-water mixture (7:3 v/v). MD simulations further indicate that the hydrophobic skeleton and hydrophilic groups of lignin could be solvated by acetone and water molecules, respectively, which significantly promoted its dissolution. Conversely, only the hydrophobic skeleton or the hydrophilic groups were solvated in organic solvent or water, respectively, inducing serious aggregation of lignin.

7.
Int J Biol Macromol ; 146: 9-17, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31899236

RESUMO

High efficiency lignin-grafted cationic polyacrylamide (L-CPA) flocculant was synthesized via "grafting to" method using acrylamide (AM), methylacryloyloxyethyltrimethyl ammonium chloride (DMC) and enzymatic hydrolysis lignin (EHL) as raw materials. The linear pre-polymer of cationic polyacrylamide (CPA) terminated with chlorine was first synthesized and then grafted onto EHL via reactions of chlorine with phenolic hydroxyl groups in lignin molecules. The synthesized L-CPA could self-assemble into octopus-like nanospheres with CPA segments dissolved in water and hydrophobic lignin skeletons concentrated in the core, which endowed the L-CPA with excellent flocculation efficiency for kaolin suspension under faintly acid, neutral or alkalescent conditions (pH = 5-9). Only a small dosage between 4.0-4.5 mg/L of L-CPA was needed for flocculation of the kaolin suspension. The charge neutralization and bridging effect was proposed for the flocculation mechanism of the lignin-grafted cationic polyacrylamide. The octopus-like L-CPA was cheap, environmentally friendly and technically feasible, showing a great prospect in wastewater treatment.

8.
Int J Biol Macromol ; 142: 551-558, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31655154

RESUMO

High performance poly(vinyl alcohol) (PVA)/lignin nanomicelle (LNM) nanocomposite films with good vapor barrier and advanced UV-shielding properties were fabricated in this study. LNM was homogeneously distributed in the PVA matrix and strong robust hydrogen bonds were successfully constructed between LNM and PVA matrix. With only 5 wt% loading of LNM into the PVA/LNM nanocomposite, the water vapor transmission rate (WVTR) was declined by about 189% compared with pure PVA. Moreover, after introducing lignin, the PVA nanocomposite films showed improved tensile strength and toughness, excellent UV-blocking and good thermal stability. As both lignin and PVA are biodegradable, this study shows a meaningful design approach for biodegradable functional nanocomposite films using cheap and easily available biomass and biodegradable raw materials.

9.
Biomacromolecules ; 20(12): 4466-4475, 2019 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-31710481

RESUMO

Simultaneous production and functionalization of cellulose nanofibrils (CNFs) for heavy metal ion removal is an economical and promising solution to expedite their use in water treatment. In this work, carboxymethylated CNFs (CMCNFs) with a carboxylate content up to 2.7 mmol/g are prepared by a combination of carboxymethylation and homogenization, which show diameters of 3.40-3.53 nm and lengths of 1210.6-383.3 nm. The effect of experimental conditions (including pH, carboxylate content, contact time, initial Cu2+ concentration) on the removal performance of CMCNFs for Cu2+ is investigated in detail. Adsorption performances of CMCNFs present a record high equilibrium Cu2+ removal capacity of 115.3 mg/g at pH 5.0. Additionally, the underlying mechanism for the removal of Cu2+ ions was uncovered by coupling the fitting results based on pseudo-second-order kinetic and Langmuir isotherm models with various characterizations such as scanning electron microscopy, energy dispersive spectroscopy (EDS), EDS mapping, X-ray photoelectron spectroscopy, atomic force microscopy, and powder X-ray diffraction. Finally, the potential application of CMCNF-2.7 with high carboxylate content in converting copper-contaminated water into drinking water was demonstrated. CMCNFs provide a new selection for the design of novel nanocellulose-based materials for water treatments.

10.
Int J Biol Macromol ; 2019 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-31743717

RESUMO

In order to develop a biomass-based superplasticizer, kraft lignin (KL) was grafted with isopentenol polyoxyethylene ether (TPEG) to prepare a novel macromonomer (KL-TPEG). It was shown that the retention ratio of the aliphatic CC bond increased from 81.07% to 90.20% with the increase of m(TPEG)/m(KL). When the grafting ratio was increased, the average number of TPEG grafted on one KL molecule was approximately 1.4, 3.1, 4.6, 6.2 and 7.6. The star-like structure was also confirmed by FT-IR, 1H NMR and GPC. KL-TPEG had favorable surface activity and dispersion stability on the cement particles. It was illustrated that the shear stress and shear viscosity of the cement slurries with KL-TPEG were significantly less than that of blank slurry. The dispersion-retention ability of KL-TPEG on the slurry was also gradually enhanced with the increase of the grafting ratio of TPEG. It was seldom reported on the biomass-based TPEG. Through modified with KL, the rheology behavior and the dispersion-retention ability of TPEG was greatly improved, and the cost of TPEG was also reduced, thus this study not only promoted the development of biomass-based macromonomer, but also helped for the high value utilization of lignin.

11.
Bioresour Technol ; 294: 122133, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31525583

RESUMO

Enzymatic hydrolysis of lignocellulose to produce bioethanol by cellulase is an important method to alleviate the energy crisis. In this paper, in order to overcome the shortcomings of low efficiency, high cost and easy deactivation of cellulase in the process of bio-refinery, pH-responsive lignin-based magnetic nanoparticles (Fe3O4/LSQA) were synthesized to immobilize and recover cellulase. It was shown that a high immobilization ratio of 55.52% for cellulase was obtained. Meanwhile, the desorption ratio was 68.27% by adjusting the pH of the system. After five reusing cycles, the desorbed cellulase retained 31.79% of the relative activity due to the pH responsiveness of Fe3O4/LSQA. These results not only provide a new idea for the recycling of cellulase, but also broaden the application of industrial lignin and increase the extra value.


Assuntos
Celulase , Nanopartículas de Magnetita , Concentração de Íons de Hidrogênio , Hidrólise , Lignina
12.
J Agric Food Chem ; 67(40): 11129-11136, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31487456

RESUMO

4-Amion-2,2,6,6-tetramethylpiperidine (Temp) was grafted into sodium lignosulfonate (SL) to obtain hindered amine-modified lignosulfonate (SL-Temp). Then, the polymer surfactant (SL-Temp-CTAB) was prepared using cetyltrimethylammonium bromide (CTAB) and SL-Temp. Obtained SL-Temp-CTAB was used as an emulsifier to prepare a green emulsifiable concentrate (EC) of avermectin (AVM), which shows good emulsifying property and storage stability. The prepared AVM green EC can form AVM-loaded microspheres with nanometer particle size distribution after emulsification in water. After ultraviolet irradiation for 70 h, the AVM retention rate of the green EC prepared using SL-Temp-CTAB was 75.8%, which is much higher than that of commercial EC (0.4%) and the green EC prepared using unmodified SL (31.4%). Moreover, the AVM green EC prepared using SL-Temp-CTAB has slow-release performance, and the release equilibrium time is 5.3 times the commercial EC. Therefore, the newly prepared AVM green EC using a lignin-based functional emulsifier shows good antiphotolysis and slow-release performance compared to the traditional EC.


Assuntos
Aminas/química , Emulsificantes/síntese química , Lignina/química , Cetrimônio/química , Emulsificantes/química , Emulsões/química , Cinética , Lignina/análogos & derivados , Espectroscopia de Ressonância Magnética , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier
13.
Food Funct ; 10(6): 3543-3555, 2019 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-31150025

RESUMO

By adjusting the polarity and conformation via the sulfomethylation modification, the bio-renewable enzymatic hydrolysis lignin (EHL) combined with alkyl polyglucoside (APG) was used as an emulsifier to stabilize the oil-in-water (O/W) high internal phase emulsions (HIPEs) for the first time under neutral conditions. The structure and sulfonation degree of the sulfomethylated lignin (EHL-XS) were characterized using gel permeation chromatography (GPC), Fourier transform infrared (FT-IR) spectroscopy, dynamic light scattering (DLS) and an automatic potentiometric titrator. The effects of the EHL-XS concentration, sulfonation degree and oil/water ratio on the microstructure and stability of HIPEs were investigated using an optical microscope and a rheometer. The results suggest that commercial lignosulfonates (LS) could not to stabilize HIPEs due to their high hydrophilicity. However, by using EHL-XS with sulfonation degree between 0.89 and 1.05 mmol g-1, up to 2.0 wt% of EHL-XS with the assistance of 3.5 wt% APG could stabilize HIPEs containing 80 vol% of internal oil phase, which were super stable and displayed no significant microstructure changes over one month. Rheological investigation indicated that HIPEs with smaller droplet size and higher oil/water ratio exhibited higher surface elasticity and stability due to the tighter overall droplet packing. In addition, the EHL-XS stabilized O/W HIPEs could be used as encapsulates for the protection and delivery of the environmentally sensitive curcumin. It was found that such HIPEs encapsulation system exhibited superior UV protection of at least 30% higher than curcumin dispersed in bulk oil after 72 h of UV irradiation or 30 days at room temperature, respectively. Meanwhile, such HIPEs within curcumin also demonstrated good inhibitory activity against S. aureus.


Assuntos
Antibacterianos/química , Antioxidantes/química , Curcumina/química , Lignina/química , Antibacterianos/farmacologia , Curcumina/farmacologia , Composição de Medicamentos , Emulsões/química , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Raios Ultravioleta
14.
J Agric Food Chem ; 67(22): 6248-6256, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31090409

RESUMO

A lignin amphoteric surfactant and betaine could enhance the enzymatic hydrolysis of lignocellulose and recover cellulase. The effects of lignosulfonate quaternary ammonium salt (SLQA) and dodecyl dimethyl betaine (BS12) on enzymatic hydrolysis digestibility, ethanol yield, yeast cell viability, and other properties of high-solid enzymatic hydrolysis and fermentation of a corncob residue were studied in this research. The results suggested that SLQA and 1 g/L BS12 effectively improved the ethanol yield through enhancing enzymatic hydrolysis. SLQA had no significant effect on the yeast cell membrane and glucose fermentation. However, 5 g/L BS12 reduced the ethanol yield as a result of the fact that 5 g/L BS12 damaged the yeast cell membrane and inhibited the conversion of glucose to ethanol. Our research also suggested that 1 g/L BS12 enhanced the ethanol yield of corncob residue fermentation, which was attributed to the fact that lignin in the corncob adsorbed BS12 and decreased its concentration in solution to a safe level for the yeast.


Assuntos
Biotecnologia/métodos , Celulose/metabolismo , Etanol/química , Etanol/metabolismo , Lignina/metabolismo , Resíduos/análise , Leveduras/metabolismo , Zea mays/microbiologia , Biocatálise , Biotecnologia/instrumentação , Celulase/química , Fermentação , Glucose/metabolismo , Hidrólise , Lignina/química , Tensoativos/química , Zea mays/metabolismo
15.
Bioresour Technol ; 283: 112-119, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30901583

RESUMO

The isoelectric point (pI) of lignin-based surfactant is an important factor in the enhancement on the enzymatic hydrolysis of lignocellulose. In this work, lignin carboxylate (LC) and quaternary ammonium lignin carboxylates (LCQ-x, x%: the mass ratio of quaternizing agent to enzymatic hydrolysis lignin) with different isoelectric points were synthesized. LC or LCQ-x with pI significantly lower or higher than 4.8 reduced the non-productive adsorption of cellulase on lignin, but for the significant inhibitory effect on cellulase activity, their enhancements on the enzymatic hydrolysis of lignocellulose were not remarkable. However, LCQ-x with pI around 4.8 preserved the cellulase activity, and significantly reduced the non-productive adsorption of cellulase, therefore remarkably enhanced the enzymatic hydrolysis. 2 g/L LC, LCQ-40 (pI = 5.0) and LCQ-100 (pI = 9.2) increased the enzymatic digestibility of pretreated eucalyptus from 35.2% to 53.4%, 95.3% and 60.4% respectively. In addition, for the excellent pH-response performance, LCQ could be efficiently recovered after enzymatic saccharification.


Assuntos
Celulase/metabolismo , Eucalyptus/metabolismo , Lignina/metabolismo , Tensoativos/metabolismo , Adsorção , Concentração de Íons de Hidrogênio , Hidrólise , Ponto Isoelétrico
16.
J Agric Food Chem ; 67(4): 1044-1051, 2019 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-30624925

RESUMO

Lignin is a kind of natural fluorescent polymer material. However, the application based on the fluorescent property of lignin was rarely reported. Herein, a noncovalent lignin-based fluorescence resonance energy transfer (FRET) system was readily constructed by physical blending method with spirolactam rhodamine B (SRhB) and lignosulfonate (LS) as the acceptor and donor groups, respectively. The FRET behavior, self-assembly, and energy transfer mechanism of SRhB/LS composite were systematically studied. It was demonstrated that LS could be used as a convenient aptamer as energy donor to construct water-soluble ratiometric sensors because of its inherent property of intramicelle energy transfer cascades. Our results not only present a facile and general strategy for producing lignin-based functional material but also provide a fundamental understanding about lignin fluorescence to promote the functional and high-valued applications of lignin fluorescence characteristic.


Assuntos
Transferência Ressonante de Energia de Fluorescência/instrumentação , Lignina/análogos & derivados , Fluorescência , Transferência Ressonante de Energia de Fluorescência/métodos , Corantes Fluorescentes/química , Concentração de Íons de Hidrogênio , Lignina/química , Rodaminas/química
17.
Carbohydr Polym ; 207: 52-58, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30600035

RESUMO

The origin, amount, hydrophilicity, charge, molecular weight and its distribution of lignin have significant influences on the enzymatic hydrolysis of lignocellulose. The enzymatic hydrolysis of lignocellulose was essentially enhanced by lignin-based polyoxyethylene ether (EHL-PEG), whereafter followed by PEG4600 and lignosulfonate (LS). The effect of LS, EHL-PEG and PEG4600 on the adsorption and enzymatic hydrolysis kinetics of cellulase on the gold surface and cellulose film was investigated by Quartz Crystal Microbalance with dissipation monitoring (QCM-D). Results showed that the interaction of LS or EHL-PEG with cellulase was electrostatic attractive and hydrophobic effect, respectively, and formed hydrophilic cellulase aggregates. LS-Cellulase peeled off the cellulose film layer by layer, while the hydrophobic phenylpropane structure of EHL-PEG-Cellulase acted as a cellulose binding domain to hydrolysis cellulose through "Hollow" effect and made cellulose become more loose and swollen. At last, a strategy to enhance the enzymatic hydrolysis of lignocellulose by lignin-based amphiphilic polymers was proposed as well.


Assuntos
Celulase/química , Lignina/química , Tensoativos/química , Adsorção , Hidrólise , Cinética , Eletricidade Estática , Trichoderma/enzimologia , Zea mays/química
18.
Food Funct ; 10(1): 355-365, 2019 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-30601504

RESUMO

Herein, oil-in-water high internal phase emulsions (HIPEs) were stabilized by lignin from different technical resources with the assistance of alkyl polyglycoside (APG) using an ultrasonic cavitation method. The results showed that the amphiphilicity of lignin determined the formation of HIPEs. Microscopic and rheological characterization indicated that the molecular weight and concentration of lignin, the APG dosage and the oil/water ratio had important influences on the microstructure and stability of the HIPEs. In addition, nutraceutical ß-carotene could be encapsulated in the oil phase of the HIPEs, which exhibited outstanding protection against photo- and thermal-oxidative degradation of ß-carotene. After storage for 30 days under room temperature/light or storage for 7 days under 55 °C/dark conditions, the retention of ß-carotene in the HIPEs was 87% to 95%, which is significantly higher than that of ß-carotene dispersed in bulk oil. In vitro digestion experiments indicated that the digestibility of the HIPEs also markedly improved. The largest release of free fatty acids was 80%. The bio-accessibility of ß-carotene in these lignin-based HIPEs also reached 60%.


Assuntos
Suplementos Nutricionais/análise , Lignina/química , beta Caroteno/química , Biomassa , Digestão , Sistemas de Liberação de Medicamentos , Emulsões/química , Glicosídeos/química , Temperatura Alta , Oxirredução , Tamanho da Partícula
19.
J Agric Food Chem ; 66(13): 3457-3464, 2018 Apr 04.
Artigo em Inglês | MEDLINE | ID: mdl-29533641

RESUMO

Alkali lignin (AL), an anionic polymer, is a byproduct of the paper industry. AL was first modified by quaternization to synthesize quaternized alkali lignin (QAL). The aim of the present study is to reveal the effects of sodium dodecyl benzenesulfonate (SDBS) on the microstructure of QAL. The interaction between SDBS and QAL is studied by means of zeta potential, fluorescence spectrophotometer, and static contact angle measurement. The results indicated that there is an electrostatic interaction and a hydrophobic interaction between QAL and SDBS. The SDBS/QAL complex can self-assemble into lignin-based colloidal spheres (LCSs) in an ethanol/water mixture, which have remarkable avermectin (AVM) encapsulation efficiency and antiphotolysis performance. The cumulative release amount of AVM encapsulated by LCS (LCS@AVM) after 72 h was 77%, and the release was still going on. The release behaviors of LCS@AVM can be controlled by adjusting the ratio (w/w) of LCS to AVM. More than 85% of AVM could be preserved even after 96 h of UV irradiation. LCS showed controlled release and UV-blocking performance for AVM.


Assuntos
Preparações de Ação Retardada/química , Portadores de Fármacos/química , Inseticidas/química , Ivermectina/análogos & derivados , Lignina/química , Tensoativos/química , Sistemas de Liberação de Medicamentos , Ivermectina/química , Cinética
20.
Bioresour Technol ; 249: 1-8, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29035726

RESUMO

Effects of nonionic surfactants on enzymatic hydrolysis of Avicel at different agitation rates and solid loadings and the mechanism were studied. Nonionic surfactants couldn't improve the enzymatic hydrolysis efficiency at 0 and 100rpm but could enhance the enzymatic hydrolysis significantly at high agitation rate (200 and 250rpm). Cellulase was easily deactivated at high agitation rate and the addition of nonionic surfactants can protect against the shear-induced deactivation, especially when the cellulase concentration was low. When 25mg protein/L of cellulase solution was incubated at 200rpm for 72h, the enzyme activity increased from 36.0% to 89.5% by adding PEG4600. Moreover nonionic surfactants can compete with enzyme in air-liquid interface and reduce the amount of enzyme exposed in the air-liquid interface. The mechanism was proposed that nonionic surfactants could enhance the enzymatic hydrolysis of Avicel by reducing the cellulase deactivation caused by shear force and air-liquid interface.


Assuntos
Celulase , Celulose , Hidrólise , Tensoativos
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