Incorporation of catechyl monomers into lignins: Lignification from the non-phenolic end: Via Diels-Alder cycloaddition?
Canonical lignification occurs via the coupling of phenolic radicals, in which chain extension can occur only from phenolic ends of growing polymer chains. Radical coupling of catechyl monomers, including caffeyl and 5-hydroxyconiferyl alcohols, gives ris
The synthesis and analysis of advanced lignin model polymers
If the lignin-first biorefinery concept becomes a reality, high quality lignins close in structure to native lignins will become available in large quantities. One potential way to utilise this renewable material is through depolymerisation to aromatic chemicals. This will require the development of new chemical methods. Here, we report the synthesis and characterisation of advanced lignin model polymers to be used as tools to develop these methods. The controlled incorporation of the major linkages in lignin is demonstrated to give complex hardwood and softwood lignin model polymers. These polymers have been characterised by 2D HSQC NMR and GPC analysis and have been compared to isolated lignins.
Lancefield,Westwood
supporting information
p. 4980 - 4990
(2015/11/16)
On the reactivity of the Melanocarpus albomyces laccase and formation of coniferyl alcohol dehydropolymer (DHP) in the presence of ionic liquid 1-allyl-3-methylimidazolium chloride
Some ionic liquids are able to dissolve wood, including lignin and lignocellulose, and thus they provide an efficient reaction media for modification of globally abundant wood-based polymers. Lignin can be modified with laccases (EC 1.10.3.2), multicopper
Lahtinen, Maarit,Viikari, Liisa,Karhunen, Pirkko,Asikkala, Janne,Kruus, Kristiina,Kilpel?inen, Ilkka
p. 169 - 177
(2013/01/15)
Hitherto unrecognized fluorescence properties of coniferyl alcohol
We instituted a quasi-quality assurance program for demonstrating coniferyl alcohol's fluorescence and fluorescence diminishment following enzymatic oxidation. The magnitude of diminishment was a measure of catalysis. High throughput screening was performed in pseudo-kinetic and endpoint modes by measuring the fluorescence at 416 nm following excitation at 290, 310 or 340 nm. Dose-response tracings were linear between two and three orders of magnitude with average limits of detection and quantitation of 1.8 and 6.9 μM coniferyl alcohol, respectively. Oxidation was evident with 0.025 μg/mL laccase or 0.003 μg/mL peroxidase or inside 5 min using 0.5 μg/mL laccase or 5 μM substrate. Sodium chloride inhibited (IC50, 25 mM) laccase oxidation of coniferyl alcohol. Fluorescence from 10 concentrations (1 to 1000 μM) of coniferyl alcohol was stable for 24 hours over 14 excitation/emission cycles at 3 different combinations of excitation and emission wavelengths. In conclusion, coniferyl alcohol absorption and fluorescence assays should facilitate biomass lignin analyses and improve delignification.
Achyuthan, Komandoor Elayavalli,Adams, Paul David,Datta, Supratim,Simmons, Blake Alexander,Singh, Anup Kumar
experimental part
p. 1645 - 1667
(2010/06/13)
An enantiocomplementary dirigent protein for the enantioselective lacease-catalyzed oxidative coupling of phenols
(+)- or (-)-plnoreslnol: that Is the question. Which of the two enantiomeric lignans is formed during laccasecatalyzed phenol coupling of (E)-coniferyl alcohol (1) depends on the dirigent protein. In the presence of the first enantiocomplementary dirigent protein AtDIR6, (-)-2 is formed (78 % ee). Preferential formation of (+)-2 is observed in the presence of the dirigent protein FiDIR1, whereas only racemic 2 is formed in the absence of dirigent proteins
Pickel, Benjamin,Constantin, Mihaela-Anca,Pfannstiel, Jens,Conrad, Juergen,Beifuss, Uwe,Schaller, Andreas
supporting information; experimental part
p. 202 - 204
(2010/03/30)
More Articles about upstream products of 1103-58-8