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10 páginas.- 5 figuras.- 2 tablas.- 50 referencias.- The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acssuschemeng.2c01274, Innovative schemes for lignocellulosic biomass refining could optimize the chemical use and biomass conversion efficiency, providing diversified biorefinery products. A new biorefinery scheme used mild alkaline-sulfite chemithermomechanical processing to pretreat sugarcane bagasse, producing highly digestible solids and diluted lignosulfonates in the black pretreatment liquor. Most of the glucan and xylan contained in the pretreated solids were converted into monosaccharides by saccharification with commercial enzymes. The undigested biomass solids remaining from the saccharification process were recycled with the existing alkaline-sulfite black pretreatment liquor. The optimized reaction conditions (159 degrees C and 13% NaOH amendment in the liquor) enhanced the lignosulfonate concentration from 7.1 +/- 0.3 to 33.5 +/- 0.7 g/L. Mass balance for the process indicates that most of the original sugarcane bagasse lignin were split into lignosulfonates contained in the resulfonation liquor (57.3%) and in the enzymatic hydrolysate (16.2%). 2D-NMR analysis of a lignosulfonate fraction recovered by ultrafiltration confirmed that approximately 9-10% of all beta-O-4' alkyl-aryl ether substructures were alpha-sulfonated. The combined chemical characteristics of the prepared lignosulfonate suggested its suitability for use in several lignosulfonate applications., This work was supported by FAPESP (grant number 2019/25867-3), CNPq (grant number 308570/2017-0), and Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brasil (CAPES)-Finance Code 001. J.R. and J.C.d.R. were funded by MCIN/AEI/10.13039/501100011033, by "ERDF A way of making Europe" (project PID2020-118968RB-I00), and by the Regional Andalusian Government, Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades/FEDER (project P20-00017).

18 páginas.- 6 figuras.- 4 tablas.- 92 referencias.-Supplementary Materials, ydroxystilbenes are a class of polyphenolic compounds that behave as lignin monomers participating in radical coupling reactions during the lignification. Here, we report the synthesis and characterization of various artificial copolymers of monolignols and hydroxystilbenes, as well as low-molecular-mass compounds, to obtain the mechanistic insights into their incorporation into the lignin polymer. Integrating the hydroxystilbenes, resveratrol and piceatannol, into monolignol polymerization in vitro, using horseradish peroxidase to generate phenolic radicals, produced synthetic lignins [dehydrogenation polymers (DHPs)]. Copolymerization of hydroxystilbenes with monolignols, especially sinapyl alcohol, by in vitro peroxidases notably improved the reactivity of monolignols and resulted in substantial yields of synthetic lignin polymers. The resulting DHPs were analyzed using two-dimensional NMR and 19 synthesized model compounds to confirm the presence of hydroxystilbene structures in the lignin polymer. The cross-coupled DHPs confirmed both resveratrol and piceatannol as authentic monomers participating in the oxidative radical coupling reactions during polymerization., This work was supported by grants from the DOE Great Lakes Bioenergy Research Center, and H.K. and J.Ra. were funded by the DOE BER Office of Science (DE- SC0018409). J.Re. and J.C.d.R. were supported by the projects AGL2017-83036-R and PID2020-118968RB-I00 (funded by MCIN/AEI/10.13039/501100011033 and, as appropriate, by “ERDF A way of making Europe”) and by the Andalusian Regional Government (project P20-00017). T.J.E. was funded by the Extreme Science and Engineering Discovery Environment (XSEDE), supported by the National Science Foundation grant number ACI-1548562. This work was made possible in part by a grant for high-performance computing resources and technical support from the Alabama Supercomputer Authority. This research was supported in part by the U.S. Department of Agriculture, U.S. Forest Service.

20 páginas.- 10 figuras.- 2 tablas.- 59 referencias.- Supplementary Information The online version contains supplementary material available at https://doi.org/10.1007/s10570-022-04573-y, Papyrus, produced from the white pith of Cyperus papyrus L., has been used for millennia as the major writing support by ancient cultures, but there was no continuous papyrus production until modern times. Therefore, papyrus production had to be rediscovered. Modern Egyptian papyrus producers claim that their sheets possess 'the same physical and chemical properties as ancient papyri'. To study if this is accurate, commercially available papyrus sheets were compared to ancient papyri and papyri produced according to Pliny's historic description. Material characterization was performed with a focus on the potentially color-bearing lignin. Two-dimensional nuclear magnetic resonance spectroscopy, derivatization followed by reductive cleavage, and pyrolysis-gas chromatography/mass spectrometry were complemented with microscopy and tests for surface pH and sodium content. The lignin data in the native pith and commercial sheets were compared to 10 ancient samples from the Papyrus Museum Vienna. The analytical data clearly show the involvement of a strong alkaline treatment followed by chlorine bleaching for commercial papyri, as expressed by higher pH values, altered lignin structures, and chlorinated lignin compounds. The inclusion of an alkaline step in ancient papyrus manufacture is discussed but dismissed, since the alkali-treatment causes a huge decrease in lignin content, that was not found for the analysed ancient specimen. We assume that this additional treatment was introduced to obtain yellowish papyrus sheets meeting optical expectations of modern spectators. Linguistic and art historic evidence indicates that such a step would not have made sense in antiquity, since it was desired to produce white papyri., Open access funding provided by University of Natural Resources and Life Sciences Vienna (BOKU). The authors acknowledge the financial support from the Austrian Biorefinery Centre Tulln (ABCT), the County of Lower Austria, the Spanish State Research Agency, the European Regional Development Fund (project AGL2017-83036-R) and the Junta de Andalucia (project P20-00017).

8 figuras.- refefencias.- Versión aceptada del artículo.- Supplementary data kiab469_Suppl. https://academic.oup.com/plphys/advance-article/doi/10.1093/plphys/kiab469/6400262#supplementary-data, Recent studies demonstrate that several polyphenolic compounds produced from beyond the canonical monolignol biosynthetic pathways can behave as lignin monomers, participating in radical coupling reactions and being incorporated into lignin polymers. Here, we show various classes of flavonoids, the chalconoid naringenin chalcone, the flavanones naringenin and dihydrotricin, and the flavone tricin, incorporate into the lignin polymer of papyrus (Cyperus papyrus L.) rind. These flavonoids were released from the rind lignin by DFRC, a chemical degradative method that cleaves the β-ether linkages, indicating that at least a fraction of each was integrated into the lignin as β-ether linked structures. Due to the particular structure of tricin and dihydrotricin, whose C-3ʹ and C-5ʹ positions at their B-rings are occupied by methoxy groups, these compounds can only be incorporated into the lignin through 4ʹ–O–β bonds. However, naringenin chalcone and naringenin have no substituents at these positions and can therefore form additional carbon-carbon linkages, including 3ʹ– or 5ʹ–β linkages that form phenylcoumaran structures not susceptible to cleavage by DFRC. Furthermore, NMR analysis indicated that naringenin chalcone can also form additional linkages through its conjugated double bond. The discovery expands the range of flavonoids incorporated into natural lignins, further broadens the traditional definition of lignin, and enhances the premise that any phenolic compound present at the cell wall during lignification could be oxidized and potentially integrated into the lignin structure, depending only on its chemical compatibility. This study indicates that papyrus lignin has a unique structure as it is the only lignin known to date that integrates such a diversity of phenolic compounds from different classes of flavonoids. This discovery will open up new ways to engineer and design lignins with specific properties and for enhanced value., This work was funded by the Spanish State Research Agency and the European Regional 51 Development Fund (project AGL2017-83036-R), the Consejería de Transformación 52 Económica, Industria, Conocimiento y Universidades, Junta de Andalucía (project P20-53 00017), the DOE Great Lakes Bioenergy Research Center (DOE BER Office of Science DE54 SC0018409), and the Austrian Biorefinery Center Tulln (ABCT). MJR thanks the Spanish 55 Ministry of Science, Innovation and Universities for a FPI fellowship (PRE2018-083267).

27 páginas.- 7 figuras.- 2 tablas.- 157 referencias.- Supplementary data The following supplementary data are available at JXB online., Phenolic metabolism is rewired during internode development and in response to cinnamyl alcohol dehydrogenase perturbation in sorghum, with different sets of genes and accumulating compounds. The molecular mechanisms associated with secondary cell wall (SCW) deposition in sorghum remain largely uncharacterized. Here, we employed untargeted metabolomics and large-scale transcriptomics to correlate changes in SCW deposition with variation in global gene expression profiles and metabolite abundance along an elongating internode of sorghum, with a major focus on lignin and phenolic metabolism. To gain deeper insight into the metabolic and transcriptional changes associated with pathway perturbations, a bmr6 mutant [with reduced cinnamyl alcohol dehydrogenase (CAD) activity] was analyzed. In the wild type, internode development was accompanied by an increase in the content of oligolignols, p-hydroxybenzaldehyde, hydroxycinnamate esters, and flavonoid glucosides, including tricin derivatives. We further identified modules of genes whose expression pattern correlated with SCW deposition and the accumulation of these target metabolites. Reduced CAD activity resulted in the accumulation of hexosylated forms of hydroxycinnamates (and their derivatives), hydroxycinnamaldehydes, and benzenoids. The expression of genes belonging to one specific module in our co-expression analysis correlated with the differential accumulation of these compounds and contributed to explaining this metabolic phenotype. Metabolomics and transcriptomics data further suggested that CAD perturbation activates distinct detoxification routes in sorghum internodes. Our systems biology approach provides a landscape of the metabolic and transcriptional changes associated with internode development and with reduced CAD activity in sorghum., This work was supported by Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) via the BIOEN Young Investigators Awards research grant (FAPESP no. 2015/02527-1). This study was financed in part by the Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior-Brasil (CAPES) -Finance Code 001, by FEDER/Agencia Estatal de Investigacion with the Spanish Projects AGL2017-83036-R and PID2020-118968RB-I00, and by Junta de Andalucia (Consejeria de Transformacion Economica, Industria, Conocimiento y Universidades, project P20_00017). IC is indebted to Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) for the research fellowship 302927/2018-2. SSF was funded for a post-doctoral fellowship (FAPESP n0. 2016/06917-1). MSS was funded for a master's fellowship (FAPESP no. 2015/18361-5). AVAP was funded for a scientific initiation fellowship (FAPESP no. 2016/06714-3). LGAL was funded for a scientific initiation fellowship (FAPESP no. 2019/14604-1).

12 páginas.- 8 figuras.- 52 referencias.- Suplemental data in http://www.plantphysiol.org/content/suppl/2019/05/03/pp.19.00255.DC1, Recent investigations have revealed that, in addition to monolignols, some phenolic compounds derived from the flavonoid and hydroxystilbene biosynthetic pathways can also function as true lignin monomers in some plants. In this study, we found that the hydroxystilbene glucosides isorhapontin (isorhapontigenin-O-glucoside) and, at lower levels, astringin (piceatannol-O-glucoside) and piceid (resveratrol-O-glucoside), are incorporated into the lignin polymer in Norway spruce (Picea abies) bark. The corresponding aglycones isorhapontigenin, piceatannol, and resveratrol, along with glucose, were released by derivatization followed by reductive cleavage (DFRC), a chemical degradative method that cleaves β-ether bonds in lignin, indicating that the hydroxystilbene glucosides are (partially) incorporated into the lignin structure through β-ether bonds. 2D-NMR analysis confirmed the occurrence of hydroxystilbene glucosides in this lignin, and provided additional information regarding their modes of incorporation into the polymer. The hydroxystilbene glucosides, particularly isorhapontin and astringin, can therefore be considered genuine lignin monomers that participate in coupling and cross-coupling reactions during lignification in Norway spruce bark., J.C.d.R, J.Re., G.M. and A.G. were funded by the Spanish projects CTQ2014-60764-JIN and AGL2017-83036-R (financed by Ministerio de Economía y Competitividad, Agencia Estatal de Investigación, AEI, and Fondo Europeo de Desarrollo Regional, FEDER), and the CSIC project 2014-40E-097; J.Ra. and H.K. were funded by the DOE Great Lakes Bioenergy Research Center (DOE BER Office of Science DE-SC0018409); J.G. and H.P. were funded by Fundação para a Ciência e a Tecnologia (FCT) under UID/AGR/00239/2013; D.N. was funded by FCT through a PhD scholarship (PD/BD/52697/2014) under the SUSFOR doctoral program.

14 páginas.- 12 figuras.- 2 tablas.- 68 referencias.- Supplementary data related to this article can be found at https://doi.org/10.1016/j.jclepro.2022.132404, We have examined a sustainable biorefinery process for the conversion of cotton gin trash (CGT), a waste from the cotton industry to multiple high value products. Herein, we found CGT native lignin to have unique features as it not only contains the p-hydroxyphenyl (H), guaiacol (G) and syringol (S) units, but structures of flavonoids, tyrosine, and phenylalanine associated with it. We have used the lignin-first approach to exploit its features in CGT and depolymerize it using argon gas and ethanol over Pd/C. The results show that 50% of the bio-aromatics is trans-isoeugenol, a precursor to produce vanillin. The cleavage of N-compounds from CGT during the fractionation process follows similar path as the rate of formation of the bio-aromatics. CGT impurities were shown to affect the reusability of the Pd/C catalyst. The fractionated cellulose-rich portion of CGT was converted to 39 mol% (80% purity) of 5-chloromethylfurfural (CMF), and a solid fuel which has a higher heating value of 20 MJ kg−1. The liquid extract, removed prior to CGT processing, was hydrogenated to produce C13–C17 liquid hydrocarbons, and the solid extract rich in nutrients is suitable for crops and plants growth. © 2022

17 páginas.- 6 figuras.- 5 tablas.- referencias.- We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI)., Rice (Oryza sativa L.) is a major cereal crop used for human nutrition worldwide. Harvesting and processing of rice generates huge amounts of lignocellulosic by-products such as rice husks and straw, which present important lignin contents that can be used to produce chemicals and materials. In this work, the structural characteristics of the lignins from rice husks and straw have been studied in detail. For this, whole cell walls of rice husks and straw and their isolated lignin preparations were thoroughly analyzed by an array of analytical techniques, including pyrolysis coupled to gas chromatography-mass spectrometry (Py-GC/MS), nuclear magnetic resonance (NMR), and derivatization followed by reductive cleavage (DFRC). The analyses revealed that both lignins, particularly the lignin from rice husks, were highly enriched in guaiacyl (G) units, and depleted in p-hydroxyphenyl (H) and syringyl (S) units, with H:G:S compositions of 7:81:12 (for rice husks) and 5:71:24 (for rice straw). These compositions were reflected in the relative abundances of the different interunit linkages. Hence, the lignin from rice husks were depleted in β–O–4′ alkyl-aryl ether units (representing 65% of all inter-unit linkages), but presented important amounts of β–5′ (phenylcoumarans, 23%) and other condensed units. On the other hand, the lignin from rice straw presented higher levels of β–O–4′ alkyl-aryl ethers (78%) but lower levels of phenylcoumarans (β–5′, 12%) and other condensed linkages, consistent with a lignin with a slightly higher S/G ratio. In addition, both lignins were partially acylated at the γ-OH of the side-chain (ca. 10–12% acylation degree) with p-coumarates, which overwhelmingly occurred over S-units. Finally, important amounts of the flavone tricin were also found incorporated into these lignins, being particularly abundant in the lignin of rice straw., his study has been funded by the Spanish Project AGL2017-83036-R (financed by Agencia Estatal de Investigación, AEI, and Fondo Europeo de Desarrollo Regional, FEDER). MJR thanks the Spanish Ministry of Science, Innovation and Universities for a FPI fellowship (PRE2018-083267). We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).

14 páginas.- 6 figuras.- 3 tablas.- referencias.- The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fpls.2021.740923/full#supplementary-material, In the present work, lignin-like fractions were isolated from several ancestral plants –including moss (Hypnum cupressiforme and Polytrichum commune), lycophyte (Selaginella kraussiana), horsetail (Equisetum palustre), fern (Nephrolepis cordifolia and Pteridium aquilinum), cycad (Cycas revoluta), and gnetophyte (Ephedra fragilis) species– and structurally characterized by pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) and two-dimensional nuclear magnetic resonance (2D-NMR) spectroscopy. Py-GC/MS yielded marker compounds characteristic of lignin units, except in the H. cupressiforme, P. commune and E. palustre “lignins,” where they were practically absent. Additional structural information on the other five samples was obtained from 2D-NMR experiments displaying intense correlations signals of guaiacyl (G) units in the fern and cycad lignins, along with smaller amounts of p-hydroxyphenyl (H) units. Interestingly, the lignins from the lycophyte S. kraussiana and the gnetophyte E. fragilis were not only composed of G- and H-lignin units but they also incorporated significant amounts of the syringyl (S) units characteristic of angiosperms, which appeared much later in plant evolution, most probably due to convergent evolution. The latter finding is also supported by the abundance of syringol derivatives after the Py-GC/MS analyses of these two samples. Regarding lignin structure, β−O−4′ alkyl-aryl ethers were the most abundant substructures, followed by condensed β−5′ phenylcoumarans and β−β′ resinols (and dibenzodioxocins in the fern and cycad lignins). The highest percentages of alkyl-aryl ether structures correlated with the higher S/G ratio in the S. Kraussiana and E. fragilis lignin-like fractions. More interestingly, apart from the typical monolignol-derived lignin units (H, G and S), other structures, assigned to flavonoid compounds never reported before in natural lignins (such as amentoflavone, apigenin, hypnogenol B, kaempferol, and naringenin), could also be identified in the HSQC spectra of all the lignin-like fractions analyzed. With this purpose, in vitro synthesized coniferyl-naringenin and coniferyl-apigenin dehydrogenation polymers were used as standards. These flavonoids were abundant in H. cupressiforme appearing as the only constituents of the moss lignin-like fraction (including 84% of dimeric hypnogenol B) and their abundance decreased in those of S. Kraussiana (with amentoflavone and naringenin representing 14% of the total aromatic units), and the two ancient gymnosperms (0.4–1.2%) and ferns (0–0.7%)., This work was funded by the Spanish Ministry of Industry, Economy and Competitiveness projects BIO2017-86559-R, AGL2017-83036-R, and PID2020-118968RB-I00, cofinanced by FEDER funds, by the Junta de Andalucía project P20-00017, and by the CSIC projects PIE-202120E019 and PIE-202040E185. We would like to acknowledge the support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).

13 pág.- 9 figuras.- 1 tabla.- 38 referencias.- The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fpls.2021.642848/full#supplementary-material, he monolignols, p-coumaryl, coniferyl, and sinapyl alcohol, arise from the general phenylpropanoid biosynthetic pathway. Increasingly, however, authentic lignin monomers derived from outside this process are being identified and found to be fully incorporated into the lignin polymer. Among them, hydroxystilbene glucosides, which are produced through a hybrid process that combines the phenylpropanoid and acetate/malonate pathways, have been experimentally detected in the bark lignin of Norway spruce (Picea abies). Several interunit linkages have been identified and proposed to occur through homo-coupling of the hydroxystilbene glucosides and their cross-coupling with coniferyl alcohol. In the current work, the thermodynamics of these coupling modes and subsequent rearomatization reactions have been evaluated by the application of density functional theory (DFT) calculations. The objective of this paper is to determine favorable coupling and cross-coupling modes to help explain the experimental observations and attempt to predict other favorable pathways that might be further elucidated via in vitro polymerization aided by synthetic models and detailed structural studies., JRa and HK were funded by the DOE Great Lakes Bioenergy Research Center (DOE Office of Science BER DE-SC0018409). JRe and JCR were funded by the Spanish Projects CTQ2014-60764-JIN and AGL2017-83036-R (financed by Agencia Estatal de Investigación, AEI and Fondo Europeo de Desarrollo Regional, FEDER).

12 páginas.- 2 figuras.- 4 tablas.- 35 referencias.- The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fbioe.2020.605854/full#supplementary-material, Epoxides of vegetable oils and free and methylated fatty acids are of interest for several industrial applications. In the present work, refined rapeseed, sunflower, soybean, and linseed oils, with very different profiles of mono- and poly-unsaturated fatty acids, were saponified and transesterified, and the products treated with wild unspecific peroxygenases (UPOs, EC 1.11.2.1) from the ascomycete Chaetomium globosum (CglUPO) and the basidiomycete Marasmius rotula (MroUPO), as well as with recombinant UPO of the ascomycete Humicola insolens (rHinUPO), as an alternative to chemical epoxidation that is non-selective and requires strongly acidic conditions. The three enzymes were able of converting the free fatty acids and the methyl esters from the oils into epoxide derivatives, although significant differences in the oxygenation selectivities were observed between them. While CglUPO selectively produced "pure" epoxides (monoepoxides and/or diepoxides), MroUPO formed also hydroxylated derivatives of these epoxides, especially in the case of the oil hydrolyzates. Hydroxylated derivatives of non-epoxidized unsaturated fatty acids were practically absent in all cases, due to the preference of the three UPOs selected for this study to form the epoxides. Moreover, rHinUPO, in addition to forming monoepoxides and diepoxides of oleic and linoleic acid (and their methyl esters), respectively, like the other two UPOs, was capable of yielding the triepoxides of alpha-linolenic acid and its methyl ester. These enzymes appear as promising biocatalysts for the environmentally friendly production of reactive fatty-acid epoxides given their self-sufficient monooxygenase activity with selectivity toward epoxidation, and the ability to epoxidize, not only isolated pure fatty acids, but also complex mixtures from oil hydrolysis or transesterification containing different combinations of unsaturated (and saturated) fatty acids., This work was received funding from the Bio Based Industries Joint Undertaking under the European Union’s Horizon 2020 Research and Innovation Programme Under Grant Agreement No. 792063 (SusBind project, https://susbind.eu) and the Consejo Superior de Investigaciones Científicas projects PIE201740E071 and PIE-202040E185.

Rice (Oryza sativa L.) is a major cereal crop used for human nutrition worldwide. Harvesting and processing of rice generates huge amounts of lignocellulosic by-products such as rice husks and straw, which present important lignin contents that can be used to produce chemicals and materials. In this work, the structural characteristics of the lignins from rice husks and straw have been studied in detail. For this, whole cell walls of rice husks and straw and their isolated lignin preparations were thoroughly analyzed by an array of analytical techniques, including pyrolysis coupled to gas chromatography-mass spectrometry (Py-GC/MS), nuclear magnetic resonance (NMR), and derivatization followed by reductive cleavage (DFRC). The analyses revealed that both lignins, particularly the lignin from rice husks, were highly enriched in guaiacyl (G) units, and depleted in p-hydroxyphenyl (H) and syringyl (S) units, with H:G:S compositions of 7:81:12 (for rice husks) and 5:71:24 (for rice straw). These compositions were reflected in the relative abundances of the different interunit linkages. Hence, the lignin from rice husks were depleted in β–O–4′ alkyl-aryl ether units (representing 65% of all inter-unit linkages), but presented important amounts of β–5′ (phenylcoumarans, 23%) and other condensed units. On the other hand, the lignin from rice straw presented higher levels of β–O–4′ alkyl-aryl ethers (78%) but lower levels of phenylcoumarans (β–5′, 12%) and other condensed linkages, consistent with a lignin with a slightly higher S/G ratio. In addition, both lignins were partially acylated at the γ-OH of the side-chain (ca. 10–12% acylation degree) with p-coumarates, which overwhelmingly occurred over S-units. Finally, important amounts of the flavone tricin were also found incorporated into these lignins, being particularly abundant in the lignin of rice straw.

13 páginas.- 8 figuras.- 3 tablas.- 63 referencias, This perspective summarizes and compares computational results for the thermodynamics of bond dissociation, coupling, and rearomatization for a number of noncanonical lignin monomer–lignol combinations that have been found to occur experimentally. The noncanonical lignin monomers discussed are tricin, caffeyl alcohol, 5-hydroxyconiferyl alcohol, and piceatannol. Among dimeric combinations, the results for bond dissociation are generally similar, but in cases for which trimers have been reported (tricin-lignol adducts), this value can be quite variable, with stereochemical and structural preferences. Among the adducts examined thus far, the energies associated with quinone methide formation and rearomatization are not dissimilar and would not impede subsequent polymerization. These fundamental studies may help to elucidate how lignin monomers are incorporated into the lignin polymer, provide leads for targeted genetic modification, and be of use in deconstruction for the production of commodity chemicals., J. Re. and J.C.d.R. were funded by the Spanish Projects CTQ2014-60764-JIN and AGL2017-83036-R (financed by Agencia Estatal de Investigacion, AEI, and Fondo Europeo de Desarrollo Regional, FEDER).

12 páginas.- 5 figuras.- 4 tablas.- 47 referencias., Lignins from different tree barks, including Norway spruce (Picea abies), eucalyptus (Eucalyptus globulus), mimosa (Acacia dealbata) and blackwood acacia (A. melanoxylon), are thoroughly characterized. The lignin from E. globulus bark is found to be enriched in syringyl (S) units, with lower amounts of guaiacyl (G) and p-hydroxyphenyl (H) units (H/G/S ratio of 1:26:73), which produces a lignin that is highly enriched in beta-ether linkages (83 %), whereas those from the two Acacia barks have similar compositions (H/G/S ratio of approximate to 5:50:45), with a predominance of beta-ethers (73-75 %) and lower amounts of condensed carbon-carbon linkages; the lignin from A. dealbata bark also includes some resorcinol-related compounds, that appear to be incorporated or intimately associated to the polymer. The lignin from P. abies bark is enriched in G units, with lower amounts of H units (H/G ratio of 14:86); this lignin is thus depleted in beta-O-4 ' alkyl-aryl ether linkages (44 %) and enriched in condensed linkages. Interestingly, this lignin contains large amounts of hydroxystilbene glucosides that seem to be integrally incorporated into the lignin structure. This study indicates that lignins from tree barks can be seen as an interesting source of valuable phenolic compounds. Moreover, this study is useful for tailoring conversion technologies for bark deconstruction and valorization., This study was funded by the Spanish project AGL2017-83036-R (co-financed by Agencia Estatal de Investigacion, AEI, and Fondo Europeo de Desarrollo Regional, FEDER). Fundacao para a Ciencia e a Tecnologia (FCT) funded both CEF (Centro de Estudos Florestais) through UID/AGR/00239/2013, and Duarte Neiva PhD scholarship (PD/BD/52697/2014) under the SUSFOR doctoral program.

16 páginas.- 6 figuras.- 131 referencias, Lignin is conventionally defined as being formed by the oxidative polymerization of three main monolignols, p-coumaryl alcohol, coniferyl alcohol, and sinapyl alcohol, that are derived from the general phenylpropanoid biosynthetic pathway. Many other phenolic compounds that are also derived from the phenylpropanoid pathway are also known to perform as genuine lignin monomers in many plants, as is the case of the monolignol ester conjugates, phenolic compounds arising from the truncated biosynthesis of monolignols, or ferulate esters. Recent investigations, however, have indicated that phenolic compounds arising from beyond the canonical phenylpropanoid pathway, namely flavonoids, hydroxystilbenes, and hydroxycinnamic amides, may also behave as authentic lignin monomers and are incorporated into the lignin in some plants, further challenging the traditional definition of lignin. This is the case of the flavone tricin that is incorporated into the lignin of grasses and other monocots, the hydroxystilbene piceatannol (together with resveratrol and isorhapontigenin, at lower levels) that has been found in the lignins of palm fruit shells, their respective O-glucosides (astringin, piceid, and isorhapontin) that are present in the lignin of Norway spruce bark, or the ferulic amides feruloyltyramine, incorporated into the lignin of tobacco and potato tubers, and diferuloylputrescine, which appears to be incorporated into maize kernel lignin. These valuable compounds are potentially available in high amounts and at low cost and may be obtained from the waste products from the processing of agricultural or forest biomass., J. C. del Rıo, J. Rencoret, and A. Gutiérrez were funded by the Spanish Project AGL2017-83036-R (financed by Agencia Estatal de Investigacion, AEI, and Fondo Europeo de Desarrollo ́ Regional, FEDER). J. Ralph and H. Kim were funded by the DOE Great Lakes Bioenergy Research Center (DOE Office of Science DE-SC0018409). T. Elder was funded by the National Science Foundation (grant number ACI-1548562).

20 páginas.- 8 figuras.- 4 tablas.- 77 referencias.- Additional supporting information may be found online in the Supporting Information section at the end of this article or in https://onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1111%2Fpce.13805&file=pce13805-sup-0001-supinfo.docx, Although cell wall polymers play important roles in the tolerance of plants to abiotic stress, the effects of salinity on cell wall composition and metabolism in grasses remain largely unexplored. Here, we conducted an in‐depth study of changes in cell wall composition and phenolic metabolism induced upon salinity in maize seedlings and plants. Cell wall characterization revealed that salt stress modulated the deposition of cellulose, matrix polysaccharides and lignin in seedling roots, plant roots and stems. The extraction and analysis of arabinoxylans by size‐exclusion chromatography, 2D‐NMR spectroscopy and carbohydrate gel electrophoresis showed a reduction of arabinoxylan content in salt‐stressed roots. Saponification and mild acid hydrolysis revealed that salinity also reduced the feruloylation of arabinoxylans in roots of seedlings and plants. Determination of lignin content and composition by nitrobenzene oxidation and 2D‐NMR confirmed the increased incorporation of syringyl units in lignin of maize roots. Salt stress also induced the expression of genes and the activity of enzymes enrolled in phenylpropanoid biosynthesis. The UHPLC–MS‐based metabolite profiling confirmed the modulation of phenolic profiling by salinity and the accumulation of ferulate and its derivatives 3‐ and 4‐O‐feruloyl quinate. In conclusion, we present a model for explaining cell wall remodeling in response to salinity., Conselho Nacional de Desenvolvimento Científico e Tecnológico, Grant/Award Number: GM/GD ‐ 141076/2016‐0; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Grant/Award Numbers: PDSE ‐ 88881.188627/2018‐01, PDSE ‐ 88881.188639/2018‐01; Czech Science Foundation, Grant/Award Number: 18‐07563S; European Regional Development Fund; Ministerio de Economía y Competitividad, Agencia Estatal de Investigación, Grant/Award Number: AGL2017‐83036‐R; Ministry of Education, Youth and Sports of the Czech Republic, Grant/Award Number: CZ.02.1.01/0.0/0.0/16_019/0000827

8 páginas.- 5 figuras.- 1 tabla.- 40 referencias, Maize (Zea mays L.) fibers and rice (Oryza sativa L.) husks are abundant and low cost by-products generated during grain milling. In this work, the composition of the lipophilic compounds present in these materials, which accounted for 4.1 % in maize fibers and 2.2 % in rice husks, was thoroughly studied by GC–MS. The most abundant lipophilic compounds identified in these residues were n-fatty acids and acylglycerols (mono-, di-, and triglycerides), that altogether accounts for up to 88 % of all extractives in maize fibers and up to 95 % in rice husks. Steroid compounds, including free and esterified sterols, hydrocarbons, and ketones were identified in both samples, being present in significant amounts in maize fibers. Tocopherols were also present in both cereal by-products, albeit in lower amounts, with α-tocopherol being the most abundant one. Minor amounts of n-fatty alcohols and high molecular esters were also found in rice husks. Maize fibers and rice husks can, therefore, be potential feedstocks to obtain valuable phytochemicals of diverse industrial interest. © 2020 The Author(s), This work has been funded by the Spanish project AGL2017-83036-R (financed by FEDER/Ministerio de Economía, Industria y Competitividad – Agencia Estatal de Investigación ).

10 páginas.- 5 figuras.- 1 tabla.- 54 referencias.- The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acssuschemeng.0c02023, Eucalyptus globulus (E. globulus) wood samples were treated in media containing acidified water and methyl isobutyl ketone (MIBK) in order to achieve the one-pot conversion of the hemicellulosic and cellulosic fractions into furfural and levulinic and formic and acetic acids, respectively. The reactions were performed under diverse operational conditions (180 or 190 °C, reaction times up to 70 min, liquid-to-solid ratios of 10 or 20 g aqueous phase/g wood, sulfuric acid concentrations of 0.5 or 1 g/100 g aqueous phase). Near-quantitative molar conversion of pentosans into furfural was achieved under conditions leading to limited generation of organic acids. In one-pot experiments performed under selected conditions, the overall yield of furfural and organic acids reached 45.2 g/100 g of wood. MIBK-soluble lignin was recovered from the organic phase by water precipitation at a yield of 17.4 g/100 g of wood, defining an effective method for the simultaneous delignification and polysaccharide conversion of E. globulus wood. The recovered lignin was characterized for structure (using pyrolysis-gas chromatography-mass spectrometry and heteronuclear single quantum coherence) and molar mass distribution. © 2020 American Chemical Society., The authors are grateful to the Spanish “Ministry of Economy and Competitiveness” for supporting this study in the framework of the project “Modified aqueous media for wood biorefineries” (reference no. CTQ2017-82962-R), partially funded by the FEDER program of the European Union. M.L. thanks “Xunta de Galicia” and the European Union (European Social Fund, ESF) for her predoctoral grant (reference no. ED481A-2017/316).

9 páginas.-- 8 figuras.-- 2 tablas.-- 35 referencias.-- The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acssuschemeng.7b02721, Catalytic depolymerization of organosolv lignin to phenolic monomers with zeolites was investigated under various operating conditions. H-USY (Si/Al molar ratio = 5) outperformed H-USY with Si/Al ratios of 50 and 250, H-BEA, H-ZSM5, and fumed SiO2 to produce the highest phenolic monomer yield from a commercial organosolv lignin in methanol at 300 °C for 1 h. It was then further investigated in the presence of acetone, ethyl acetate, methanol, and methyl isobutyl ketone (MIBK) on the depolymerization of organosolv bagasse lignin (BGL). The total highest phenolic monomer yield of 10.6 wt % was achieved with MIBK at 350 °C for 1 h with a catalyst loading of 10 wt %. A final total phenolic monomer yield of 19.4 wt % was obtained with an initial H2 pressure of 2 MPa under similar processing conditions. The main phenolic monomers obtained are guaiacol (7.9 wt %), 4-ethylphenol (6.0 wt %), and phenol (3.4 wt %). The solvent properties were used to account for the differences in phenolic monomer yields obtained with different organic solvents., The authors express their sincere appreciation to the Joint raduate School of Energy and Environment (JGSEE), Petchra Pra Jom Klao Doctoral Scholarship, King Mongkut’s University of Technology Thonburi (KMUTT), Thailand Research Fund (RTA5980006), and the Queensland University of Technology (QUT), Australia, for financing this project. The authors thank Dr. Jorge Rencoret and Dr. Ana Gutierrez, who were partly funded by the Spanish projects AGL2014-53730-R and CTQ2014-60764-JIN (cofinanced by FEDER funds), for PyGC/MS analysis of the lignins.

11 páginas.- 6 figuras.- 5 tablas.- 57 referencias, Papyrus (Cyperus papyrus L.) is a plant with high productivity rate that is considered an interesting raw material for obtaining biofuels and biomaterials. In the present work, the composition and structural features of the lignins present in the rind and pith of papyrus culms have been studied. The analyses revealed that the lignins from both parts of papyrus culms differed greatly not only in their contents but also in composition and structure. In the rind, the lignin represented up to 27.0% (dry-matter) and was composed mainly of G-units (H:G:S composition of 4:63:33), while the lignin in the pith (15.7% dry-matter) presented a slightly higher amount of S-units (H:G:S composition of 8:43:49). These lignins also presented considerable amounts of cinnamates (p-coumarates and ferulates) incorporated. The differences in composition influenced the content of the lignin inter-unit linkages. Thus, the rind lignin presented lower amounts of β–O–4′ ether linkages (77% of all identified linkages) and higher content of condensed structures, such as phenylcoumarans (15%), resinols (2%), dibenzodioxocins (3%), and spirodienones (2%), while the pith lignin contained more β–O–4′ ethers (85% of all identified linkages) and lower amounts of phenylcoumarans (11%), tetrahydrofurans (2%), and spirodienones (2%). Moreover, 2D NMR analyses revealed that the lignins from papyrus were highly acylated at the γ-OH (40% acylation in the rind, and 60% acylation in the pith). DFRC analyses proved that p-coumarates were the main acylating groups, and that they were predominantly acylating the S-lignin units. Finally, the analyses also showed the presence of important amounts of the flavanone tricin in the rind lignin and, at lower amounts, in the pith lignin. © 2021 The Authors, This work was partially funded by the Spanish Project AGL2017-83036-R (financed by Agencia Estatal de Investigación, AEI and Fondo Europeo de Desarrollo Regional, FEDER) and by Consejería de Transformación Económica, Industria, Conocimiento y Universidades, Junta de Andalucía, Spain (project P20_00017). MJR thanks the Spanish Ministry of Science, Innovation and Universities for a FPI fellowship (PRE2018-083267). FB, TR, and AP were funded by the Austrian Biorefinery Center Tulln (ABCT).

ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes., The lignins from different anatomical parts of macaúba (Acrocomia aculeata) palm fruit, namely stalks, epicarp, and endocarp, were studied. The lignin from stalks was enriched in S-lignin units (S/G 1.2) and β-ether linkages (84% of the total) and was partially acylated at the γ-OH of the lignin side-chains (26% lignin acylation), predominantly with p-hydroxybenzoates and acetates. The epicarp lignin was highly enriched in G-lignin units (S/G 0.2) and consequently depleted in β-ethers (65%) and enriched in condensed structures such as phenylcoumarans (24%) and dibenzodioxocins (3%). The endocarp lignin was strikingly different from the rest and presented large amounts of piceatannol units incorporated into the polymer. This resulted in a lignin polymer depleted in β-ethers but enriched in condensed structures and linked piceatannol moieties. The incorporation of piceatannol into the lignin polymer seems to have a role in seed protection., This study has been funded by the Spanish Projects AGL2014-53730-R, CTQ2014-60764-JIN, and AGL2017-83036-R (cofinancedby FEDER funds) and the CSIC project 2014-40E097. John Ralph and Hoon Kim were funded by the DOE Great Lakes Bioenergy Research Center (DOE BER Office of Science DE-FC02-07ER64494)., We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI).

9 páginas.- 4 figuras.- 1 tabla.- 27 referencias, Papyri belong to the oldest writing grounds in history. Their conservation is of the highest importance in preserving our cultural heritage, which is best achieved based on an extensive knowledge of the materials’ constituents to choose a tailored conservation approach. Thermogravimetric Analysis (TGA) has been widely employed to quantify cellulose and lignin in papyrus sheets, yielding reported lignin contents of 25% to 40%. In this work, the TGA method conventionally used for papyrus samples was repeated and compared to other lignin determination approaches (Klason-lignin and acetyl bromide-soluble lignin). TGA can lead to a large overestimation of the lignin content of commercial papyrus sheets (~27%) compared to the other methods (~5%). A similar overestimation of the lignin content was found for the pith and rind of the native papyrus plant. We concluded that the TGA method should, therefore, not be used for lignin quantification., Funding by the Austrian Biorefinery Center Tulln (ABCT) and the County of Lower Austria is greatly acknowledged. J.C.d.R., J.R. and M.J.R were funded by the Spanish State Research Agency and the European Regional Development Fund (project AGL2017-83036-R), and by the Junta de Andalucía (project P20-00017).

10 páginas.-- 3 figuras.-- 3 tablas.-- 50 referencias, Sugarcane bagasse and straw, two major agro-industrial byproducts generated by the sugarcane industry, contain significant amounts of carbohydrates that can be hydrolyzed and then converted into ethanol or other valuable compounds. However, access to them is limited by the presence of lignin, a recalcitrant polymer that protects cell-wall polysaccharides from enzymatic hydrolysis. This work demonstrates the ability of an enzymatic pretreatment, based on the laccase from Pycnoporus cinnabarinus, and 1-hydroxybenzotriazole as mediator, to remove and/or modify lignin in sugarcane bagasse and straw residues, improving their subsequent saccharification. Up to 27% and 31% decreases of relative lignin content in ground sugarcane bagasse and straw, respectively, were achieved by the laccase-mediator pretreatment followed by alkaline peroxide extraction. Moreover, the lignin removal directly correlated with improvements in enzymatic saccharification, increasing glucose releases by around 39% and 46% for bagasse and straw, respectively, compared with those of the corresponding controls. Lignin depolymerization and degradation were made evident in the 2D-NMR spectra by a significant reduction in the number of aliphatic side chains involved in the main β-O-4′ and β-5′ interunit linkages, together with a remarkable removal of p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) lignin units as well as the associated p-coumarates and ferulates, with respect to polysaccharides, This study has been funded by the Spanish projects AGL2014-53730-R and CTQ2014-60764-JIN (cofinanced by FEDER funds) and the EU-project INDOX (KBBE-2013-7-613549).

32 páginas.-- 6 figuras.-- 4 tablas.-- 53 referencias.-- SUPPORTING INFORMATION The following data are available online as complementary information: Assignments of lignin 13C/1H correlation signals in the 2D HSQC spectra of the MWL isolated from eucalyptus, wheat straw and spruce; size and zeta potential of the MWL measured in aqueous dispersions at different background electrolyte concentrations; water contact angles before and after CTec2 and CBH-I adsorption; AFM images of wheat straw films corresponding to SPR sensograms after rinsing with 50 mM background electrolyte; schematics of the different scenarios for enzymes adsorption on the surfaces for the calculation of surface coverage., Lignins were isolated from spruce, wheat straw and eucalyptus by using the milled wood lignin (MWL) method. Functional groups and compositional analyses were assessed via 2D NMR and 31P to realize their effect on enzyme binding. Films of the lignins were fabricated and ellipsometry, atomic force microscopy and water contact angle measurements were used for their characterization and to reveal the changes upon enzyme adsorption. Moreover, lignin thin films were deposited on quartz crystal microgravimetry (QCM) and surface plasmon (SPR) resonance sensors and used to gain further insights into the lignin-cellulase interactions. For this purpose, a commercial multicomponent enzyme system and a monocomponent Trichoderma reesei exoglucanase (CBH-I) were considered. Strong enzyme adsorption was observed on the various lignins but compared to the multicomponent cellulases, CBH-I displayed lower surface affinity and higher binding reversibility. This resolved prevalent questions related to the affinity of this enzyme with lignin. Remarkably, a strong correlation between enzyme binding and the S/G ratio was found for the lignins, which presented a similar hydroxyl group content (31P NMR): higher protein affinity was determined on isolated spruce lignin (99% G units) while the lowest adsorption occurred on isolated eucalyptus lignin (70% S units). The effect of electrostatic interactions in enzyme adsorption was investigated by SPR, which clearly indicated that the screening of charges allowed more extensive protein adsorption. Overall, this work furthers our understanding of lignin-cellulase interactions relevant to biomass that has been subjected to no or little pretreatment and highlights the widely contrasting effects of the nature of lignin, which gives guidance to improve lignocellulosic saccharification and related processes, This study was partially funded by the INDOX EU-project (KBBE-2013-7-613549); the LIGNOCELL, LIGNIN, NOESIS, and BIORENZYMERY Spanish MICINN (co-financed by FEDER funds) projects (AGL2011-25379, CTQ2014-60764-JIN, BIO2014-56388 R and AGL2014-53730-R) and the CSIC Project 201440E097. A.P. is grateful to the Spanish MINECO for a FPI fellowship. O.J.R. would like to thank the Academy of Finland for funding through its Centers of Excellence Program (2014–2019), under Project 132723612 HYBER.

12 páginas.- 13 figuras.- 1 tabla.- 41 referencias.- Supporting information: Cartesian coordinates for low energy conformation of all compounds, optimized using M06-2X/6-311++G(d,p)., Recent experimental work has revealed that the hydroxystilbene piceatannol can function as a monomeric unit in the lignification of palm fruit endocarp tissues. Results indicated that piceatannol homo-couples and cross-couples with monolignols through radical reactions and is integrally incorporated into the lignin polymer. The current work reports on the thermodynamics of the proposed reactions using density functional theory calculations. The results indicated that, in general, the energetics of both homo-coupling and cross-coupling are not dissimilar from those of the monolignol coupling, demonstrating the compatibility of piceatannol with the lignification process. Moreover, the DFT methods appear to predict the correct courses of post-coupling rearomatization reactions. © 2019, This work used the Extreme Science and Engineering Discovery Environment (XSEDE), which is supported by National Science Foundation grant number ACI-1548562 . Specifically, it used the Bridges system at the Pittsburgh Supercomputing Center (PSC) and Stampede2 at the Texas Advanced Computing Center ( TACC ), both via MCB-090159 to GTB. JR and HK Were funded by the DOE Great Lakes Bioenergy Research Center (DOE Office of Science BER DE-FC02-07ER64494 and DE-SC0018409 ). JRe and JCdR were funded by the Spanish Projects CTQ2014-60764-JIN and AGL2017-83036-R (financed by Agencia Estatal de Investigación, AEI and Fondo Europeo de Desarrollo Regional, FEDER). GTB acknowledges support from the US Department of Energy Office of Energy Efficiency and Renewable Energy Bioenergy Technologies Office under Contract No. DE-AC36-08GO28308 to the National Renewable Energy Laboratory.

8 páginas.-- 6 figuras.-- 3 tablas.-- 34 referencias., Following an integrated approach, Eucalyptus nitens wood samples were subjected to consecutive stages of aqueous fractionation and organosolv delignification, in order to separate hemicelluloses (mainly converted into soluble products from the aqueous stage) from lignin (largely converted into soluble fragments in the organosolv stage) and from cellulose (accumulated in the solid phase from pulping). The compositions of selected reaction media were studied by selected spectrophotometric, spectrometric, chromatographic, and nuclear magnetic resonance methods; and the solid phases from treatments were studied by diffractometry and scanning electron microscopy. The experimental information from the above tasks provides a deep insight on the yields, properties and potential applications of the target fractions in the scope of biorefineries., The authors are grateful to the Spanish Ministry of Economy and Competitivity for supporting this study in the framework of the research project ‘‘Modified aqueous media for wood Biorefineries’’ (reference CTQ2017-82962-R), partially funded by the FEDER program of the European Union.

5 páginas.-- 4 figuras.-- 24 referencias.-- Supporting information for this article can be found under: http://dx.doi.org/10.1002/anie.201604915., Este artículo está en abierto en el enlace de la revista y puede descargar el pdf. original, A new heme–thiolate peroxidase catalyzes the hydroxylation of n-alkanes at the terminal position—a challenging reaction in organic chemistry—with H2O2 as the only cosubstrate. Besides the primary product, 1-dodecanol, the conversion of dodecane yielded dodecanoic, 12-hydroxydodecanoic, and 1,12-dodecanedioic acids, as identified by GC–MS. Dodecanal could be detected only in trace amounts, and 1,12-dodecanediol was not observed, thus suggesting that dodecanoic acid is the branch point between mono- and diterminal hydroxylation. Simultaneously, oxygenation was observed at other hydrocarbon chain positions (preferentially C2 and C11). Similar results were observed in reactions of tetradecane. The pattern of products formed, together with data on the incorporation of 18O from the cosubstrate H218O2, demonstrate that the enzyme acts as a peroxygenase that is able to catalyze a cascade of mono- and diterminal oxidation reactions of long-chain n-alkanes to give carboxylic acids., The research was financed by the project NCN DEC-2012/07/B/ST5/02448 and the research program P1-0055 of the Slovenian Research Agency. Authors thank Prof. Mojca Cepic and Prof. Hideo Takezoe for valuable discussions.

11 páginas.-- 9 figuras.-- 6 tablas.-- 26 referencias., The chemical composition and thermal behavior of the pulp and kernel oils extracted from the macauba (Acrocomia aculeata) palm fruit were investigated. The analyses revealed that the composition of the pulp and kernel oils were completely different from each other. While the pulp oil was dominated by unsaturated triglycerides (ca. 78.5% of all identified compounds), followed by significant amounts of diglycerides (ca. 13.2%) and minor amounts of free fatty acids (ca. 5.6%) and sterols (1.5%), the kernel oil was largely dominated by saturated triglycerides with shorter chains (accounting for ca. 98.6% of all identified compounds) and with trace amounts of free fatty acids (0.9%), sterols (0.2%) and monoglycerides (0.3%). Saponification of the macauba pulp and kernel oils produced different distribution of fatty acids, with the pulp oil being enriched in unsaturated fatty acids (ca. 70%, principally oleic and linoleic acids), and the kernel oil being enriched in saturated fatty acids (ca. 70%), with a predominance of lauric acid. Thermal analyses (thermogravimetric, TGA, and Differential Scanning Calorimetry, DSC) indicated the high thermal stability of these oils, with the pulp oil having higher thermal stability than the kernel oil. The macauba pulp and kernel oils can thus be viewed as promising feedstocks for obtaining highly valuable compounds for the food, cosmetic and pharmaceutical industries, and also as a source for the production of biodiesel., This study has been funded by the Spanish projects AGL2011-25379 and AGL2014-53730-R (co-financed by FEDER funds), the CSIC project 2014-40E-097 and the EU-project INDOX (KBBE- 2013-7-613549). Anderson B. Evaristo thanks the CAPES—Brazil for scholarship, University of Valladolid (UVa—ES) and University Federal of Vic¸ osa (UFV—BR) for their support in carrying out the study.

10 páginas.-- 5 figuras.-- 10 tablas.-- 39 referencias.-- Electronic supplementary information (ESI) available. See DOI:10.1039/c6ra20081h, In this study, the effects of an alkali-acid purification process on the properties of eucalyptus lignin isolated from a methyl isobutyl ketone (MIBK)/methanol/water-based organosolv fractionation process were evaluated. The results showed that the treatment reduced the content of carbohydrates, ash, nitrogen and sulfur, and improved lignin solubility (up to 218%) in five organic solvents (acetone, methanol, ethanol, tetrahydrofuran and dimethyl sulfoxide) and removed lignin fractions with smaller molecular weights. However, analysis by Py-GC/MS, solid state NMR and 2D-HSQC NMR indicated that the alkali-acid treatment process did not cause changes to the monomeric lignin subunits and linkages of the lignin polymer. The treated lignin showed slightly higher thermal stability at temperatures, We would also like to express our sincere appreciation of the Royal Golden Jubilee scholarship (RGJ) (Thailand), Thailand Research Fund (Thailand), and Queensland University of Technology (QUT, Australia) for financing this project.

9 páginas.-- 6 figuras.-- 2 tablas.-- 37 referencias, The composition of lipophilic phytochemicals in sugarcane bagasse and straw, the two major residues of sugarcane processing, was investigated in detail by gas chromatography and mass spectrometry. The composition of the lipids from sugarcane bagasse and straw were completely different from each other. While the extracts of sugarcane bagasse were dominated by n-aldehydes (ca. 48% of all identified lipids) and n-fatty alcohols (ca. 23%) with lower amounts of n-fatty acids (10%) and steroid ketones (14%), the extracts from sugarcane straw were strongly dominated by n-fatty acids (accounting for ca. 60% of all identified compounds) with significant amounts of steroid compounds, particularly sterols (10%) and steroid ketones (14%). Tocopherols and triterpenols were also found, being particularly abundant among the extractives of sugarcane straw. Sugarcane bagasse and straw can thus be considered as promising feedstocks for obtaining highly valuable phytochemicals of nutraceutical or pharmaceutical interest., This study has been funded by the Spanish projects AGL2011-25379 and AGL2014-53730-R (co-financed by FEDER funds), the CSIC project 2014-40E-097 and the EU-project INDOX (KBBE-2013-7-613549). Alessandro G. Lino thanks CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior) for financial support. C.F. Lima and J.L. Colodette are grateful to National Council for Scientific and Technological Development (CNPq) for research fellowships.

13 páginas.-- 3 figuras.-- 3 tablas.-- 47referencias.-- : The following are available online at http://www.mdpi.com/1996-1944/11/11/2211/s1.__ This article belongs to the Special Issue Biodegradable Polymeric Composites: Development and Industrial Applications, A method consisting of the alkaline hydrolysis of tomato pomace by-products has been optimized to obtain a mixture of unsaturated and polyhydroxylated fatty acids as well as a nonhydrolysable secondary residue. Reaction rates and the activation energy of the hydrolysis were calculated to reduce costs associated with chemicals and energy consumption. Lipid and nonhydrolysable fractions were chemically (infrared (IR) spectroscopy, gas chromatography/mass spectrometry (GC-MS)) and thermally (differential scanning calorimetry (DSC), thermogravimetric analysis (TGA)) characterized. In addition, the fatty acid mixture was used to produce cutin-based polyesters. Freestanding films were prepared by non-catalyzed melt-polycondensation and characterized by Attenuated Total Reflected-Fourier Transform Infrared (ATR-FTIR) spectroscopy, solid-state nuclear magnetic resonance (NMR), DSC, TGA, Water Contact Angles (WCA), and tensile tests. These bio-based polymers were hydrophobic, insoluble, infusible, and thermally stable, their physical properties being tunable by controlling the presence of unsaturated fatty acids and oxygen in the reaction. The participation of an oxidative crosslinking side reaction is proposed to be responsible for such modifications., This research was funded by the Andalusian Regional Government (Junta de Andalucía) under the Motriz Program, project No. P11-TEP-7418 and to the Spanish Ministerio de Economía y Competitividad and Fondo Europeo de Desarrollo Regional (FEDER), projects No. AGL2015-65246-R and AGL2017-83036-R

10 páginas.-- 2 tablas.-- 5 figuras.-- 53 referencias, There is considerable variability in the ability of seagrass ecosystems to sequester organic carbon (Corg) in their sediments, which act as natural carbon sinks contributing to climate change mitigation. In this work, we studied the chemistry of two Posidonia seagrass species aiming to elucidate whether differences in chemical composition might explain differences in their Corg sequestration capacity. Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) and Thermally assisted Hydrolysis and Methylation (THM) GC-MS data showed a remarkable difference in phenolic compound patterns between P. oceanica and P. australis bulk plants and individual organs (leaves, sheaths, roots and rhizomes). The lignin of P. australis generates a series of p-hydroxyphenyl (H), guaiacyl (G) and syringyl (S) products that are typical of herbaceous plants, whereas P. oceanica is particularly rich in p-hydroxybenzoic acid (pBA) derivatives. The structural characteristics of the lignins were further investigated by two-dimensional Nuclear Magnetic Resonance (2D-NMR) spectroscopy and Derivatization Followed by Reductive Cleavage (DFRC), focusing on sheath tissues. The analyses confirmed important differences in the lignin content (19.8% in P. australis and 29.5% in P. oceanica) and composition between the two species; intriguingly, the cell-walls of P. oceanica sheaths were highly enriched in pBA, a component that was completely absent in P. australis. 2D-NMR and DFRC data further revealed that pBA was esterified to the lignin, acylating the γ-OH of the lignin side-chain. Interestingly, P. oceanica lignin presented an extremely high degree of p-hydroxybenzoylation in both guaiacyl (73%) and syringyl (61%) lignin units; the highest p-hydroxybenzoylation degree reported in plant lignins to date. It is tempting to conclude that the higher Corg storage capacity of P. oceanica ecosystems might be related to the higher abundance of pBA-rich lignin and its recalcitrant nature., This study has been funded by the Spanish projects CTQ2014-60764-JIN and AGL2017-83036-R (co-financed by FEDER funds). OS was supported by an ARC DECRA DE170101524.

8 páginas.-- 3 figuras.-- 3 tablas.-- 26 referencias.-- Supporting information for this article is available on the WWW under https://doi.org/10.1002/cctc.201800849, Recently discovered fungal unspecific peroxygenases from Marasmius rotula and Chaetomium globosum catalyze the epoxidation of unsaturated fatty acids (FA) and FA methyl esters (FAME), unlike the well-known peroxygenases from Agrocybe aegerita and Coprinopsis cinerea. Reactions of a series of unsaturated FA and FAME with cis-configuration revealed high (up to 100%) substrate conversion and selectivity towards epoxidation, although some significant differences were observed between enzymes and substrates with the best results being obtained with the C. globosum enzyme. This and the M. rotula peroxygenase appear as promising biocatalysts for the environmentally-friendly production of reactive FA epoxides given their self-sufficient monooxygenase activity and the high conversion rate and epoxidation selectivity, This work was funded by the BIORENZYMERY (AGL2014-53730-R) project of the Spanish MINECO (co-financed by FEDER) and by the CSIC 201740E071 project. H. Lund (Novozymes) is acknowledged for rCciUPO

páginas.-- 11 figuras.-- 1 tabla.-- 48 referencias, The structure of the phenolic polymer in maize grain fibers, with 5.5% Klason lignin content, has been studied. For this, the milled wood lignin (MWL) and dioxane lignin (DL) preparations were isolated and analyzed. The data indicated that the lignin in maize fibers was syringyl-rich, mostly involved in β-aryl ether, resinol and phenylcoumaran substructures. 2D-NMR and derivatization followed by reductive cleavage (DFRC) also revealed the occurrence of associated ferulates together with trace amounts of p-coumarates acylating the γ-OH of lignin side-chains, predominantly on S-lignin units. More interesting was the occurrence of diferuloylputrescine, a ferulic acid amide, which was identified by 2D-NMR and comparison with a synthesized standard, that was apparently incorporated into this lignin. A phenylcoumaran structure involving a diferuloylputrescine coupled through 8−5′ linkages to another diferuloylputrescine (or to a ferulate or a guaiacyl lignin unit) was found, providing compelling evidence for its participation in radical coupling reactions. The occurrence of diferuloylputrescine in cell walls of maize kernels and other cereal grains appears to have been missed in previous works, perhaps due to the alkaline hydrolysis commonly used for compositional studies., JCdR, JRe, and AG were funded by the Spanish projects CTQ2014-60764-JIN and AGL2017- 83036-R (financed by Agencia Estatal de Investigación, AEI, and Fondo Europeo de Desarrollo Regional, FEDER), and the CSIC project 2014-40E-097; JRa, and HK were funded by the DOE Great Lakes Bioenergy Research Center (DOE BER Office of Science DE-FC02-07ER64494 and DE-SC0018409).