Studies on the dehydrogenative polymerizations (DHPs) of monolignol β-glycosides: Part 4. Horseradish peroxidase-catalyzed copolymerization of isoconiferin and isosyringin

Holzforschung ◽  
2008 ◽  
Vol 62 (5) ◽  
Author(s):  
Yuki Tobimatsu ◽  
Toshiyuki Takano ◽  
Hiroshi Kamitakahara ◽  
Fumiaki Nakatsubo
Keyword(s):  
Horseradish Peroxidase ◽  
Heterogeneous Reaction ◽  
Reaction System ◽  
Spectroscopic Studies ◽  
Degree Of Polymerization ◽  
Coniferyl Alcohol ◽  
Water Soluble ◽  
Sinapyl Alcohol ◽  
Homogeneous Phase ◽  
Heterogeneous Phase

Abstract Horseradish peroxidase (HRP)-catalyzed dehydrogenative copolymerization of guaiacyl (G)-type monolignol glycoside (isoconiferin, coniferyl alcohol γ-O-β-d-glucopyranoside, iso-G) and syringyl (S)-type monolignol glycoside (isosyringin, sinapyl alcohol γ-O-β-d-glucopyranoside, iso-S) were performed in continuous dehydrogenation mode (end-wise polymerization) to result in the formation of water-soluble lignin-like copolymers (iso-G/S-DHPs) in a homogeneous phase. The yield of iso-G/S-DHP increased with increasing iso-G content in the mixture of monomers from 23% (iso-G/iso-S 0:100) to 81% (iso-G/iso-S 50:50). The degree of polymerization (DP) of the resulting iso-G/S-DHP also increased proportionally from 7 (iso-G/iso-S 0:100) to 27 (iso-G/iso-S 50:50) as the iso-G content increased. It is obvious that iso-G plays an important role in the polymerization of iso-S. A similar tendency was also observed in conventional copolymerization of coniferyl alcohol (G-alc) and sinapyl alcohol (S-alc). The highest DP for DHP obtained in the conventional system was only ∼10 due to the heterogeneous reaction system. As the HRP-catalyzed monomer consumption rate of iso-S was greatly enhanced by addition of iso-G as a co-monomer, radical transfer from iso-G to iso-S seems to be plausible. Conventional copolymerization of G-alc and S-alc also supports this view. Spectroscopic studies and alkaline nitrobenzene oxidation analyses indicated that iso-G/S-DHPs had typical lignin structures composed of both G and S units. It was confirmed that the copolymerization behavior of the glycosides iso-G and iso-S in a homogeneous phase are well reflected by that of the monolignols G-alc and S-alc in a heterogeneous phase. Results also indicated that the presence of G-type co-monomers sensitively affects the polymerization of S-type monomers.

Studies on the dehydrogenative polymerizations of monolignol β-glycosides. Part 2: Horseradish peroxidase-catalyzed dehydrogenative polymerization of isoconiferin

Holzforschung ◽  
2006 ◽  
Vol 60 (5) ◽  
pp. 513-518 ◽  
Author(s):  
Yuki Tobimatsu ◽  
Toshiyuki Takano ◽  
Hiroshi Kamitakahara ◽  
Fumiaki Nakatsubo
Keyword(s):  
Horseradish Peroxidase ◽  
Water Solubility ◽  
Homogeneous System ◽  
Degree Of Polymerization ◽  
Coniferyl Alcohol ◽  
Water Soluble ◽  
Optimum Conditions ◽  
Spectroscopic Analyses ◽  
Dehydrogenation Polymer ◽  
Dehydrogenative Polymerization

Abstract Dehydrogenative polymerization of isoconiferin (IC; coniferyl alcohol γ-O-β-D-glucopyranoside) catalyzed by horseradish peroxidase (HRP) was carried out. The polymerization of IC proceeded in a homogeneous system, resulting in a water-soluble dehydrogenation polymer (IC-DHP). The degree of polymerization (DP) of IC-DHP was significantly higher than that of a standard dehydrogenative polymer (CA-DHP) obtained from coniferyl alcohol (CA) in a heterogeneous system. Under optimum conditions, the DP of IC-DHP was 44 (M n=1.5×104), whereas that for CA-DHP was only 11 (M n=3.0×103, as acetate). Spectroscopic analyses confirmed that IC-DHP has a lignin-like structure containing D-glucose moieties attached to the lignin side-chains. The D-glucose unit introduced into γ-O position of CA essentially influenced the water solubility and molecular mass of the resulting DHP.

Studies on the dehydrogenative polymerization of monolignol β-glycosides. Part 6: Monitoring of horseradish peroxidase-catalyzed polymerization of monolignol glycosides by GPC-PDA

Holzforschung ◽  
2010 ◽  
Vol 64 (2) ◽  
Author(s):  
Yuki Tobimatsu ◽  
Toshiyuki Takano ◽  
Hiroshi Kamitakahara ◽  
Fumiaki Nakatsubo
Keyword(s):  
Horseradish Peroxidase ◽  
Reaction System ◽  
Water Soluble ◽  
Quinone Methide ◽  
Efficient Production ◽  
Hydroxyl Groups ◽  
Photodiode Array Detection ◽  
Dehydrogenative Polymerization

Abstract Horseradish peroxidase (HRP)-catalyzed dehydrogenative polymerization of guaiacyl (G) and syringyl (S)-type monolignol γ-O-glucosides, isoconiferin (iso-G) and isosyringin (iso-S), which contain a hydrophilic glucosyl unit on γ-position of coniferyl alcohol and sinapyl alcohol, respectively, was monitored by gel permeation chromatography coupled with photodiode array detection (GPC-PDA). Contrary to the conventional dehydrogenative polymerization of monolignols, the polymerization of the glycosides produces water-soluble synthetic lignins (DHPs) in a homogeneous aqueous phase. Taking advantage of this unique reaction system, the method was developed to follow the changes of molecular weights in the course of DHP formations. Moreover, PDA detection permits determination of oligomeric S-type quinone methide intermediates (QMs) formed as stable transient compounds during polymerization of iso-S. A detailed comparison of the polymerization profiles revealed entirely different behaviors of G- and S-type monomers. The data strongly support the view that the low reactivity of oligomeric S-type QMs impedes the formation of DHPs from S-type monomers. In copolymerization of G- and S-type monomers, it is conceivable that G-type phenolic hydroxyl groups serve as good nucleophilic reactants to scavenge S-type QMs resulting in efficient production of DHPs. As a consequence, the present approach can be a powerful tool to study the in vitro dehydrogenative polymerization providing further mechanistic insights into lignin polymerization in vivo.

scholarly journals Getting Graft Cellulose Copolymers and Acrylic Monomers

2019 ◽  
Vol 8 (4) ◽  
pp. 719-723 ◽  
Keyword(s):  
Molecular Weight ◽  
Graft Copolymerization ◽  
Spectroscopic Studies ◽  
Degree Of Polymerization ◽  
Potassium Persulfate ◽  
Water Soluble ◽  
Active Centers ◽  
Solvent Absorption ◽  
Adsorption Interaction ◽  
Acrylic Monomers

Graft copolymers of acrylic monomers with cotton cellulose were obtained. The dependence of the degree and efficiency of grafting of acrylic acid and methyl methacrylate to cellulose on the concentration of monomer and initiator was investigated. Pre-adsorption of the initiator in the macromolecules of cellulose leads to an increase in the efficiency of the grafting. The efficiency of grafting is higher in those systems in which the initiator used is insoluble in the monomer solvent. Absorption of cellulose with an aqueous solution of the initiator - potassium persulfate, followed by removal of water was done. The advantage of using a water-soluble initiator is that during subsequent processing with a solution of monomer in an organic solvent, the desorption of the active centers does not occur. An increase in the concentration of theinitiator leads to an increase in the degree of grafting, a slight increase in the efficiency of the grafting, a significant decrease in the degree of polymerization and the molecular weight of the graft chains. In a heterogeneous process, an increase in the efficiency of grafting with an increase in the concentration of theinitiator is promoted by the additional adsorption interaction of the initiator molecules with the surface of cellulose. With an increase in the concentration of monomers, the overall degree of conversion slightly increases, the efficiency of grafting slightly decreases, the degree of grafting and the molecular weight of the graft chains increase significantly. The mechanism of graft copolymerization was investigated by comparative analysis of the IR and PMR spectra of cellulose, potassium persulfate, acrylic monomers and products of their interaction. Due to the results of spectroscopic studies, a scheme of graft copolymerization reactions has been proposed. The active centers of graft copolymerization are formed as a result of the reductive interaction of potassium persulfate, water and cellulose macromolecules.

Reactivity of syringyl quinone methide intermediates in dehydrogenative polymerization. Part 2: pH effect in horseradish peroxidase-catalyzed polymerization of sinapyl alcohol

Holzforschung ◽  
2010 ◽  
Vol 64 (2) ◽  
Author(s):  
Yuki Tobimatsu ◽  
Toshiyuki Takano ◽  
Hiroshi Kamitakahara ◽  
Fumiaki Nakatsubo
Keyword(s):  
Horseradish Peroxidase ◽  
Uv Spectroscopy ◽  
Ph Effect ◽  
Water Soluble ◽  
Quinone Methide ◽  
Photodiode Array Detection ◽  
Sinapyl Alcohol ◽  
Acidic Conditions ◽  
Dehydrogenative Polymerization ◽  
Catalyzed Polymerization

Abstract The solvent pH effect in the horseradish peroxidase (HRP)-catalyzed polymerization of sinapyl alcohol (S-alc) and analogously, sinapyl alcohol γ-O-glucoside (isosyringin, iso-S) was investigated particularly focusing on the behavior of syringyl-type quinone methide intermediates (S-type QMs) under acidic conditions. At first, the HRP-catalyzed polymerization of iso-S at pH 6.5–2.5, which produces water-soluble dehydrogenation polymer (DHP) intermediates in a homogeneous phase, was monitored by UV spectroscopy and gel permeation chromatography with photodiode array detection (GPC-PDA). Under acidic conditions at pH below 4.5, unstablilized S-type QMs from iso-S are rapidly quenched resulting in efficient productions of DHPs, although substantial loss of HRP activity and the resulting insufficient polymerization were inevitable at pH below 3.5. In addition, it was found that a small addition of guaiacyl-type comonomer (isoconiferin, iso-G) effectively promotes the polymerization of iso-S under acidic conditions, in which the comonomer serves as a radical mediator to facilitate the HRP-catalyzed oxidations of iso-S. Next, the HRP-catalyzed polymerization of S-alc at various pH values was conducted and the resulting DHPs were characterized by GPC and NMR measurements. The yields of isolated DHPs significantly increased as solvent pH decreased below 4.5. The structural analyses of the DHPs demonstrated that reaction selectivity of S-type QMs during the polymerization drastically changed at pH below 4.5: they react efficiently with water molecules as solvent leading to the formation of benzyl alcohol type β-O-4 substructures preferentially to the formation of α-O-aryl type substructures. Consequently, the data in this study demonstrated that acidic conditions at pH below 4.5 are favored in the dehydrogenative polymerization of S-alc from the viewpoint of the reactivity of S-type QMs.

scholarly journals Controlled Depolymerization of Cellulose Fibres Isolated from Lignocellulosic Biomass Wastes

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Suh Cem Pang ◽  
Lee Ken Voon ◽  
Suk Fun Chin
Keyword(s):  
Lignocellulosic Biomass ◽  
Acid Catalyst ◽  
Degree Of Polymerization ◽  
Second Order ◽  
Water Soluble ◽  
Cellulose Fibres ◽  
Amberlyst 15 ◽  
Pseudo Second Order ◽  
Chain Lengths ◽  
Optimized Conditions

Various types of lignocellulosic biomass wastes (LBW) had been successfully converted into cello-oligomers with different chain lengths via a controlled depolymerization process. Cellulose fibres isolated from LBW samples were dissolved with room temperature ionic liquid (RTIL) in the presence of an acid catalyst, Amberlyst 15 DRY. The effects of reaction time on the degree of polymerization and yields of water-insoluble cello-oligomers formed were studied. Besides, the yields of water-soluble cello-oligomers such as glucose and xylose were also determined. The depolymerization of cellulose fibres isolated from LBW was observed to follow both second-order and pseudo-second order kinetics under specific conditions. As such, cello-oligomers of controllable chain lengths could be obtained by adjusting the duration of depolymerization process under optimized conditions.

Horseradish peroxidase-catalyzed hydrogelation consuming enzyme-produced hydrogen peroxide in the presence of reducing sugars

Soft Matter ◽  
2019 ◽  
Vol 15 (10) ◽  
pp. 2163-2169 ◽  
Author(s):  
Enkhtuul Gantumur ◽  
Shinji Sakai ◽  
Masaki Nakahata ◽  
Masahito Taya
Keyword(s):  
Hydrogen Peroxide ◽  
Horseradish Peroxidase ◽  
Reducing Sugars ◽  
Reaction System ◽  
System P

Three kinds of reducing sugars are applied to HRP-catalyzed hydrogelation to promote the generation of H2O2 in the reaction system.

scholarly journals Controlled allylation of polyelectrolytes: a deep insight into chemical aspects and their applicability as building blocks for robust multilayer coatings

2019 ◽  
Vol 91 (6) ◽  
pp. 983-995
Author(s):  
Thi-Thanh-Tam Nguyen ◽  
Sabrina Belbekhouche ◽  
Rémi Auvergne ◽  
Benjamin Carbonnier ◽  
Daniel Grande
Keyword(s):  
Heterogeneous Reaction ◽  
Experimental Tests ◽  
Building Blocks ◽  
Water Soluble ◽  
Basic Solution ◽  
Solution Ph ◽  
Covalent Crosslinking ◽  
Electrolytic Properties ◽  
Potential Applications ◽  
Post Modification

Abstract Polyelectrolytes (PEs) bearing easily derivatizable functions for possible post-modification under mild conditions can find a broad range of applications in various fields. The present paper describes the successful controlled side-chain allylation of two types of PEs: polyamine-based polycations, i.e. poly(allylamine hydrochloride) (PAH) and branched polyethyleneimine (PEI), and strong polyanions, i.e. poly(sodium vinyl sulfonate) (PVS) and poly(sodium 4-styrene sulfonate) (PSS). PSS has been largely investigated in the literature, while PVS is much less commonly explored. The allylation of each type presents its own drawback, i.e. heterogeneous reaction in the case of strong polyanions and instability of partially protonated allylated polyamine products. Nevertheless, all encountered difficulties could be solved and thoroughly elucidated by different experimental tests. This partial allyl-functionalization does not affect the electrolytic properties of the newly allylated PEs, as evidenced by the effective construction of two series of polyelectrolyte multilayer (PEM) films, namely PEI-ene (PSS-ene/PAH-ene)4 and PEI-ene (PVS-ene/PAH-ene)4, the latter being one of the rare examples developed in the literature. The presence of allyl groups on the PE side-chains allows for the stabilization of the resulting PEM films via thiol-ene photo-crosslinking in the presence of a water-soluble dithiol crosslinker. In order to fix permanently the resulting crosslinked PEM films on substrates, the covalent crosslinking occurs not only between different C=C bonds on PE layers but also with those present on substrates preliminarily functionalized with allyl groups via sulfur–gold chemistry. The robustness of both resulting crosslinked PEM films under strongly basic solution (pH 14) is validated by Quartz Crystal Microbalance (QCM) measurements. The versatility and effectiveness of the present approach is expected to find potential applications in different scientific and technological fields.

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