New biobased polyurethane (PU) coatings with high lignin content were developed and characterized in this work. These materials were based on a α,ω-diisocyanate monomer (1,4-bis­(4-isocyanato-2-methoxyphenoxy)­butane, VA-NCO) obtained from lignin-derived vanillic acid and its further cross-linking reaction with three different nonchemically modified technical lignins obtained from different pulping processes, namely, mild acetone organosolv, kraft, and soda. After determining the optimal VA-NCO/lignin mass ratio for each type of lignin, an in-depth characterization of the obtained PU coatings highlighted their high biomass content, effective cross-linking, improved thermal stability, hydrophobic character, good adhesion performance on different types of substrates, and tunable mechanical response. These properties were found to be well-correlated to the chemical–physical features of the parent lignins used (namely, molecular weight, glass transition temperature, distribution of phenylpropane subunits, and −OH content), thereby suggesting the possibility to predictively tailor the characteristics of such biobased PU coatings by lignin selection. The results of this study demonstrate that the reaction of a lignin-derived biobased diisocyanate with different chemically unmodified technical lignins represents an interesting pathway for the production of thermosetting PU coatings with a high biomass content that can find application as high-performance biobased materials alternative to traditional petroleum-based platforms.

The β-O-4 aryl ether linkages represent about 50% of all ethers in various lignins. At least three enzymatic\ud steps are required to break them down: a NAD+-dependent C-α dehydrogenase (such as LigD and L), a\ud glutathione lyase that releases guaiacol (i.e., a β-etherase such as LigE and F), and a glutathione-dependent\ud lyase (i.e., LigG). In this work the LigD, L, E, F, and G fromSphingobium sp. SYK-6 were overexpressed in E.\ud coli and purified with high yields. After characterizing the stability and kinetic properties of LigD and L on\ud the lignin model compound GGE (1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)propane-1,3-\ud diol) and the thermostability of all five recombinant Lig enzymes, the experimental conditions for GGE\ud bioconversion could be optimized (i.e., pH 9.0, 25 °C, ≈0.1 mg mL−1 of each enzyme, and 0.5 mM racemic\ud substrate). Under optimal conditions, and by recycling NADH using the L-lactate dehydrogenase–pyruvate\ud system, GGE was fully converted into the final products 3-hydroxy-1-(4-hydroxy-3-methoxyphenyl)propan-\ud 1-one and guaiacol in <2 hours. Differently from what was previously reported, this result and chiral HPLC\ud analyses demonstrated that LigG catalyzes the glutathione-dependent thioether cleavage of both β(R)- and\ud β(S)-isomer intermediates produced by LigE and LigF β-etherases: this allowed, for the first time, reaching\ud 100% conversion of GGE. Altogether, the recombinant five-enzyme Lig system represents a component well\ud suited for a multienzymatic process, comprising well-known ligninolytic activities (such as peroxidases and\ud laccases), devoted to transforming selected lignins into aromatic compounds as an alternative to the oil\ud source.\ud 1. Introduction\ud Lignocellulose refers to plant dry matter (biomass or the socalled\ud lignocellulosic biomass). It is composed of carbohydrate\ud polymers (cellulose, hemicellulose) and an aromatic\ud polymer (lignin) and represents the most promising feedstock.\ud Although burning lignin still represents a valuable contribution\ud for saving fossil sources, lignin also offers perspectives\ud in terms of higher value-added applications. In fact,\ud after th

An industrial wheat straw lignin was fractionated by a multistep process involving microfiltration followed by two membrane-assisted ultrafiltration steps starting from an aqueous solvent solution. The parent lignin and the different fractions were fully characterized in terms of chemical composition and physicochemical properties by gel permeation chromatography, gas chromatography−mass spectrometry, high-performance liquid chromatography, thermogravimetric analysis, differential scanning calorimetry analysis, and Fourier transform infrared spectroscopy. The results show that the proposed process allows us to selectively control the molar mass distribution of the fractions and the related dependent properties. This strategy offers a better understanding of the structural complexity of soda pulp raw lignin and emerges as an essential tool for lignin valorization in the context of material science and preparative organic chemistry.