Designing biomass lignins for the biorefinery

4 páginas.- 3 figuras. 17 referencias.- Comunicación oral presentada en el 16th European Workshop on Lignocellulosics and Pulp (EWLP) Gothenburg, Sweden, June 28 – July 1, 2022As ever more component monomers are discovered, lignin can no longer be regarded as deriving from just the three canonical monolignols. Pathway intermediates and additional products of truncated biosynthesis are now established lignin monomers. The array of acylated monolignols continues to expand. Game-changing findings have demonstrated that phenolics from alternative pathways, including flavonoids and hydroxystilbenes, are also involved in lignification, expanding the traditional concept. Beyond the basic science intrigue, these findings propound exciting new avenues for valorizing lignins, or for producing more readily extractable or depolymerizable lignins, in crop and bioenergy plants.We further acknowledge lots of colleagues and collaborators, and funding from the Swiss National Science Foundation (Synergia) grant # CRS115_180258, and the DOE Great Lakes Bioenergy Research Center (DOE BER Office of Science DE-SC0018409).N

Distribution and outcomes of a phenotype-based approach to guide COPD management: Results from the CHAIN cohort

Rationale: The Spanish guideline for COPD (GesEPOC) recommends COPD treatment according to four clinical phenotypes: non-exacerbator phenotype with either chronic bronchitis or emphysema (NE), asthma-COPD overlap syndrome (ACOS), frequent exacerbator phenotype with emphysema (FEE) or frequent exacerbator phenotype with chronic bronchitis (FECB). However, little is known on the distribution and outcomes of the four suggested phenotypes. Objective: We aimed to determine the distribution of these COPD phenotypes, and their relation with one-year clinical outcomes. Methods: We followed a cohort of well-characterized patients with COPD up to one-year. Baseline characteristics, health status (CAT), BODE index, rate of exacerbations and mortality up to one year of follow-up were compared between the four phenotypes. Results: Overall, 831 stable COPD patients were evaluated. They were distributed as NE, 550 (66.2%); ACOS, 125 (15.0%); FEE, 38 (4.6%); and FECB, 99 (11.9%); additionally 19 (2.3%) COPD patients with frequent exacerbations did not fulfill the criteria for neither FEE nor FECB. At baseline, there were significant differences in symptoms, FEV1 and BODE index (all p<0.05). The FECB phenotype had the highest CAT score (17.1±8.2, p<0.05 compared to the other phenotypes). Frequent exacerbator groups (FEE and FECB) were receiving more pharmacological treatment at baseline, and also experienced more exacerbations the year after (all p<0.05) with no differences in one-year mortality. Most of NE (93%) and half of exacerbators were stable after one year. Conclusions: There is an uneven distribution of COPD phenotypes in stable COPD patients, with significant differences in demographics, patient-centered outcomes and health care resources use

Tricin-lignins: occurrence and quantitation of tricin in relation to phylogeny

12 páginas.-- 4 figuras.-- 3 tablas.-- 59 referencias.-- Additional Supporting Information may be found in the online version of this article. http://dx.doi.org/10.1111/tpj.13315Tricin [5,7-dihydroxy-2-(4-hydroxy-3,5-dimethoxyphenyl)-4H-chromen-4-one], a flavone, was recently established as an authentic monomer in grass lignification that likely functions as a nucleation site. It is linked onto lignin as an aryl alkyl ether by radical coupling with monolignols or their acylated analogs. However, the level of tricin that incorporates into lignin remains unclear. Herein, three lignin characterization methods: acidolysis; thioacidolysis; and derivatization followed by reductive cleavage; were applied to quantitatively assess the amount of lignin-integrated tricin. Their efficiencies at cleaving the tricin-(4′–O–β)-ether bonds and the degradation of tricin under the corresponding reaction conditions were evaluated. A hexadeuterated tricin analog was synthesized as an internal standard for accurate quantitation purposes. Thioacidolysis proved to be the most efficient method, liberating more than 91% of the tricin with little degradation. A survey of different seed-plant species for the occurrence and content of tricin showed that it is widely distributed in the lignin from species in the family Poaceae (order Poales). Tricin occurs at low levels in some commelinid monocotyledon families outside the Poaceae, such as the Arecaceae (the palms, order Arecales) and Bromeliaceae (Poales), and the non-commelinid monocotyledon family Orchidaceae (Orchidales). One eudicotyledon was found to have tricin (Medicago sativa, Fabaceae). The content of lignin-integrated tricin is much higher than the extractable tricin level in all cases. Lignins, including waste lignin streams from biomass processing, could therefore provide a large and alternative source of this valuable flavone, reducing the costs, and encouraging studies into its application beyond its current roles.The authors thank the China Scholarship Council, State Education Department, for supporting living expenses for Wu Lan’s PhD Program in the Department of Biological System Engineering, University of Wisconsin, Madison, USA. WL, FL, SK and JRa were funded by the DOE Great Lakes Bioenergy Research Center (DOE BER Office of Science DE-FC02-07ER64494). JR e was funded by the Spanish Project CTQ2014-60764-JIN (co-financed by FEDER funds), BGS and PJH by the University of Auckland, and JRa, BGS and PJH in part by US Department of Energy, Energy Biosciences Program, Grant #DE-AI02-06ER64299 (2006).Peer reviewe

Hydroxystilbene dehydrogenation polymers and copolymers with monolignols (Abstracts)

Comunicación presentada en el 257th ACS National Meeting & Exposition, 31 March 2019 to 04 April 2019, Orlando, FloridaN

Designer lignins: inspirations from Nature

Lignin remains one of the most significant barriers to the efficient utilization of lignocellulosic substrates, in processes ranging from ruminant digestibility to indus-trial pulping, and in the current focus on biofuels production. Inspired largely by the recalcitrance of lignin to biomass processing, plant engineering efforts have routinely sought to alter lignin quantity, composition, and structure by exploiting the inherent plasticity of lignin biosynthesis. More recently, researchers are attempting to strategically designplants for increased degradability by incorporating monomers that lead to a lower degree of polymerisation, reduced hydrophobicity, fewer bonds to other cell wall constituents, or novel chemically labile linkages in the polymer backbone.[1]In addition, the incorporation of value-added structures could help valorise lignin. Designer lignins may satisfy the biological requirement for lignification in plants while improving the overall efficiency of biomass utilisation.Researchers are now already beginning todesignlignins, by introducing novel phenolic precursors into the plant lignification process, to improve the ease with which the resulting lignins can be removed from the cell wall. Although possibilities abound, maintaining plant health is paramount and, ultimately, the plants themselves will dictate which of these approaches can be tolerated. Onesuch method, via the so-called ‘zip-lignin’ approach, is showing particular promise.[2-4]Poplar trees have been engineered to incorporate monolignol ferulate conjugates into the lignification process, resulting inthe introduction of readily cleavable ester linkages into the backbone of the polymer, and resulting in significantly improved processing. Various applications for which these altered trees seem well suited will be discussed. We’ll describe recent advances, including getting the monolignol ferulate conjugates into grasses, in which we were concerned that the natural p-coumaroylation of mono-lignols might compete. In addition, now that we have sensitive methods for determin-ing if/when/whether plants are making monolignol ferulate conjugates and using them for lignification (methods that have not previously been available), it appears that Nature herself may have already been exploring this avenue. We’ll provide insight into the plants that seem to be doingthis and try to elucidate how. [The question of why is likely to require a lot more time, research, and insight]. Finally, we’ll note other avenues, inspired by Nature, for lignin modification that have potential value for various processes.For example,the ramifications of finding that grasses are using aphenolic, tricin, a flavonoid from beyond the monolignol biosynthetic pathway to start lignin chainsare interesting indeed.[5,6] [1] Y. Mottiar, R. Vanholme, W. Boerjan, J. Ralph, S. D. Mansfield, Curr. Opin. Biotechnol. 2016, 37, 190-200. [2] J. H. Grabber, R. D. Hatfield, F. Lu, J. Ralph, Biomacromolecules 2008, 9, 2510-2516. [3] J. Ralph, Phytochem. Rev. 2010, 9, 65-83.[4] C. G. Wilkerson, S. D. Mansfield, F. Lu, ...,D. Padmakshan, F. Unda, J. Rencoret, J. Ralph, Science 2014, 344, 90-93. [5] J. C. del Río, J. Rencoret, P. Prinsen, Á. T. Martínez, J. Ralph, A. Gutiérrez, J. Agric. Food Chem. 2012, 60, 5922-5935. [6] W. Lan,F. Lu, M. Regner, Y. Zhu, J. Rencoret, S. A. Ralph, U. I. Zakai, K. Morreel, W. Boerjan, J. Ralph, Plant Physiol. 2015, 167, 1284-1295Peer Reviewe

Protein amino acid residues and a new monolignol conjugate in lignins and their interference with p-hydroxyphenyl (H) unit estimation

Póster presentado en el Lignin Gordon Research Conference Towards Viable Solutions for Lignin Valorization August 5 - 10, 2018, (Easton, MA), USPeer reviewe

Protein amino acid residues and a new monolignol conjugate in lignins and their interference with p-hydroxyphenyl (H) unit estimation - Póster presentación

4 páginas.-- 3 figuras.-- 7 referencias.-- Poster presentación en el 15th European Workshop on Lignocellulosics and Pulp June 26-29, 2018 Aveiro, PortugalWe elucidated the detailed structures of the residual protein peaks, phenylalanine and tyrosine, in 2D NMR spectra from corn cob and kenaf samples. Phenylalanine¿s 3/5 correlation peak is superimposed on the peak from typical lignin p-hydroxyphenyl (H-unit) structures, causing an overestimation of the H units. We used a protease to remove the protein residues from the ballmilled cell walls. Additionally, we also identified a new monolignol conjugate, ML-benzoate (BA), in the cell wall samples of leaf tissues from Canary Island date palm (Phoenix canariensis) and also a small amount from macaúba (Acrocomia aculeata (Jacq.) Lodd. ex Mart.) endocarp (and a trace in the stem) along with stilbenes, also causing an overestimation of the H units.This work was supported by grants from the DOE Great Lakes Bioenergy Research Center (DOE BER Office of Science DE-FC02-07ER64494), and Spanish projects CTQ2014-60764-JIN and AGL2017-83036-R (financed by Agencia Estatal de Investigación, AEI, and Fondo Europeo de Desarrollo Regional, FEDER).Peer Reviewe

'Designing' biomass lignins for the biorefinery

Comunicación oral presentada en la XXIX Conferencia Internacional sobre Polifenoles y la 9ª Conferencia de Taninos, del 16 al 20 de julio de 2018 Madison, WI, USAMAIN CONCLUSION Lignin biosynthesis is uniquely malleable, allowing a variety of phenolics to be utilized as lignin monomers and therefore allowing some tailoring of its structure, reactivity, and value. We are now at a juncture where actual ‘design’ of the polymer can be contemplated and envisioning an ideal polymer for lignin valorization can be entertained. INTRODUCTION Evidence continues to mount regarding lignins’ inherent structural malleability from studies on lignin pathway mutants and transgenics as well as on various ‘natural’ plants discovered to possess unusual lignins. [1-4] Most of the monomers previously considered were from the monolignol biosynthetic pathway itself. More recently, phenolics from beyond the monolignol pathway have been shown to be authentic monomers in some plants, including the flavone tricin in all grasses (and beyond),[5,6] various hydroxystilbenes in some palm endocarp tissues,[7,8] and now possible nitrogenous compounds such a putrescine in maize kernel lignin. [9] As we have frequently noted from some time back, but not in print until 2008: “any phenolic transported to the lignifying zone of the cell wall can, subject to simple chemical compatibility, be incorporated into the polymer.”[10] That does not automatically mean that the r sulting polymer will be well tolerated by the plant, but researchers are now able to contemplate some degree of actually designing lignins for improved utilization and value, and muse over what might constitute a lignin that is ideally suited for conversion to phenolic monomers, adding value to the biorefinery. RESULTS AND DISCUSSION As José Carlos del Río will cover the other pathways that are now known to contribute to lignification, we shall provide an update to how lignins can be designed to fall apart more readily during processing (the so-called ‘zip-lignin’ approach) and describe a lignin that is natural in some tissues (but not yet in plant stems) that is one example of an ideal lignin. Zip-lignins. We have now shown that it is possible to engineer weak bonds (esters) into the lignin backbone,[11] thus facilitating lignin depolymerization during pretreatment or processing (such as in pulping).[12] It turns out that Nature is already making lignins this way, at low levels, in a variety of plants;[13] we may have even inadvertently selected for this trait in targeting woody species that pulp most easily, for example. An “ideal lignin.” It is now a realistic juncture to posit the characteristics for an “ideal lignin” archetype for biomass processing. For the depolymerization of the polymer to monomers, one ideotype is a lignin that has at least the following three characteristics. First, it should be stable under acidic conditions to prevent condensation and the generation of undesired new C–C bonds, during pretreatment. Second, it should contain only ether (C–O) inter-unit linkages in its backbone so that it can be fully depolymerized. Last, it should be generated in planta from a single phenylpropanoid monomer to allow the production of the simplest array of compounds. C-lignin, such as that found in vanilla and various cacti seed coats, [14,15] is essentially a homopolymer synthesized almost purely by β–O–4-coupling of caffeyl alcohol with the growing polymer chain, producing benzodioxanes as the dominant unit in the polymer, is an example of such an “ideal lignin” that can, in principle, be depolymerized to a single monomeric product in high yield. Here we will describe the ideal nature of this lignin via a revised compositional characterization of the vanilla seedcoat fiber, new features of the C-lignin’s reactivity and stability, and our successful attempts at converting it to monomers in near-quantitative yields.REFERENCES [1] Y. Mottiar, R. Vanholme, W. Boerjan, J. Ralph, S. D. Mansfield, Current Opinion in Biotechnology 2016, 37, 190. [2] R. Vanholme, K. Morreel, C. Darrah, P. Oyarce, J. H. Grabber, J. Ralph, W. Boerjan, New Phytologist 2012, 196, 978. [3] J. Ralph, Phytochemistry Reviews 2010, 9, 65. [4] W. Boerjan, J. Ralph, M. Baucher, Annual Review of Plant Biology 2003, 54, 519. [5] W. Lan, J. Rencoret, F. Lu, S. D. Karlen, B. G. Smith, P. J. Harris, J. C. del Rio, J. Ralph, The Plant Journal 2016, 88, 1046. [6] J. C. del Río, J. Rencoret, P. Prinsen, Á. T. Martínez, J. Ralph, A. Gutiérrez, Journal of Agricultural and Food Chemistry 2012, 60, 5922. [7] J. C. del Río, J. Rencoret, A. Gutiérrez, H. Kim, J. Ralph, Plant Physiology 2017, 174, 2072. [8] J. Rencoret, H. Kim, A. B. Evaristo, A. Gutiérrez, J. Ralph, J. C. del Río, Journal of Agricultural and Food Chemistry 2018, 66, 138. [9] J. C. del Río, J. Rencoret, A. Gutierrez, H. Kim, J. Ralph, Journal of Agricultural & Food Chemistry 2018, in press (accepted 4/20/2018). [10] J. Ralph, G. Brunow, P. J. Harris, R. A. Dixon, P. F. Schatz, W. Boerjan, in Recent Advances in Polyphenol Research, Vol. 1 (Eds.: F. Daayf, A. El Hadrami, L. Adam, G. M. Ballance), Wiley-Blackwell Publishing, Oxford, UK, 2008, pp. 36-66. [11] C. G. Wilkerson, S. D. Mansfield, F. Lu, S. Withers, J.-Y. Park, S. D. Karlen, E. Gonzales-Vigil, D. Padmakshan, F. Unda, J. Rencoret, J. Ralph, Science 2014, 344, 90. [12] S. Zhou, T. Runge, S. D. Karlen, J. Ralph, E. Gonzales-Vigil, S. D. Mansfield, ChemSusChem 2017, 10, 3565. [13] S. D. Karlen, C. Zhang, M. L. Peck, R. A. Smith, D. Padmakshan, K. E. Helmich, H. C. A. Free, S. Lee, B. G. Smith, F. Lu, J. C. Sedbrook, R. Sibout, J. H. Grabber, T. M. Runge, K. S. Mysore, P. J. Harris, L. E. Bartley, J. Ralph, Science Advances 2016, 2, e1600393. [14] F. Chen, Y. Tobimatsu, L. Jackson, J. Nakashima, J. Ralph, R. A. Dixon, The Plant Journal 2013, 73, 201. [15] F. Chen, Y. Tobimatsu, D. Havkin-Frenkel, R. A. Dixon, J. Ralph, P Natl Acad Sci USA 2012, 109, 1772.This work was funded in part by the DOE Great Lakes Bioenergy Research Center (DOE BER Office of Science DE-FC02-07ER64494 and DE-SC0018409).Peer reviewe