El doctor en química D. Jorge Rencoret Pazos galardonado con el premio de investigación 'Real Maestranza de Caballeria de Sevilla' a investigadores jóvenes en su convocatoria de 2012

2 páginas.-- Artículo sobre la entrega del premio de investigación convocado en 2012 para investigadores jóvenes por la "Real Maestranza de Caballería" de Sevilla. Escrito por el Dr. Pedro J. Sánchez Sot

Maize tricin-oligolignol metabolites and their implications for monocot lignification

Lignin is an abundant aromatic plant cell wall polymer consisting of phenylpropanoid units in which the aromatic rings display various degrees of methoxylation. Tricin [5,7-dihydroxy-2-(4-hydroxy-3,5-dimethoxyphenyl)-4H-chromen-4-one], a flavone, was recently established as a true monomer in grass lignins. To elucidate the incorporation pathways of tricin into grass lignin, the metabolites of maize (Zea mays) were extracted from lignifying tissues and profiled using the recently developed 'candidate substrate product pair' algorithm applied to ultra-high-performance liquid chromatography and Fourier transform-ion cyclotron resonance-mass spectrometry. Twelve tricin-containing products (each with up to eight isomers), including those derived from the various monolignol acetate and p-coumarate conjugates, were observed and authenticated by comparisons with a set of synthetic tricin-oligolignol dimeric and trimeric compounds. The identification of such compounds helps establish that tricin is an important monomer in the lignification of monocots, acting as a nucleation site for starting lignin chains. The array of tricin-containing products provides further evidence for the combinatorial coupling model of general lignification and supports evolving paradigms for the unique nature of lignification in monocots

Laccase-Mediator Pretreatment of Wheat Straw Degrades Lignin and Improves Saccharification

14 páginas.-- 4 figuras.-- 4 tablas.-- 49 referenciasThe authors thank Dr. Angulo for performing the NMR analyses that were acquired on a Bruker AVANCE III 500-MHz instrument from the NMR facilities of the General Research Services of the University of Seville (SGI CITIUS)gricultural by-products such as wheat straw are attractive feedstocks for the production of second-generation bioethanol due to their high abundance. However, the presence of lignin in these lignocellulosic materials hinders the enzymatic hydrolysis of cellulose. The purposes of this work are to study the ability of a laccase-mediator system to remove lignin improving saccharification, as a pretreatment of wheat straw, and to analyze the chemical modifications produced in the remaining lignin moiety. Up to 48 % lignin removal from ground wheat straw was attained by pretreatment with Pycnoporus cinnabarinus laccase and 1-hydroxybenzotriazole (HBT) as mediator, followed by alkaline peroxide extraction. The lignin removal directly correlated with increases (∼60 %) in glucose yields after enzymatic saccharification. The pretreatment using laccase alone (without mediator) removed up to 18 % of lignin from wheat straw. Substantial lignin removal (37 %) was also produced when the enzyme-mediator pretreatment was not combined with the alkaline peroxide extraction. Two-dimensional nuclear magnetic resonance (2D NMR) analysis of the whole pretreated wheat straw material swollen in dimethylsulfoxide-d6 revealed modifications of the lignin polymer, including the lower number of aliphatic side chains involved in main β-O-4′ and β-5′ inter-unit linkages per aromatic lignin unit. Simultaneously, the removal of p-hydroxyphenyl, guaiacyl, and syringyl lignin units and of p-coumaric and ferulic acids, as well as a moderate decrease of tricin units, was observed without a substantial change in the wood polysaccharide signals. Especially noteworthy was the formation of Cα-oxidized lignin units during the enzymatic treatment.This study was 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 (201440E097) Project. A.P. thanks the Spanish MINECO for a FPI fellowship. A. Lomascolo and E. Record from INRA (Marseille, France) are acknowledged for the P. cinnabarinus laccase, and H. Lund and M. Tovborg from Novozymes (Bagsvaerd, Denmark) for Celluclast 1.5L and Novozyme 188.Peer reviewe

Oxidation of model lipids representative for main paper pulp lipophilic extractives by the laccase-mediator system.

Several model lipids representative for main paper pulp lipophilic extractives - including alkanes, fatty alcohols, fatty acids, resin acids, free and esterified sterols, and triglycerides – were treated with Pycnoporus cinnabarinus laccase in the presence of 1-hydroxybenzotriazole as mediator. The reaction products were analyzed by GC and GC-MS. The laccase alone decreased the amount of some unsaturated lipids, however, the most rapid and extensive lipid modification was obtained with the laccase-mediator system. Most unsaturated lipids were largely oxidized and the dominant oxidation products detected were epoxy and hydroxy-fatty acids from fatty acids, and free and esterified 7-ketosterols and steroid ketones from sterols and sterol esters. In contrast, saturated lipids were not modified, although some of them were oxidized when the enzymatic reactions were carried out in the presence of unsaturated lipids. The results obtained are discussed in the context of enzymatic control of pitch deposits, to explain the removal of lipid mixtures during laccase-mediator treatment of different pulp types.This study was funded by the BIORENEW EU-project (NMP2-CT-2006-026456) and the Spanish MEC (BIO2007-28719-E). Beldem (Andenne, Belgium) is acknowledged for laccase supply. S.M. thanks the Spanish CSIC and CELESA for an I3P contract and J.R thanks the CSIC for an I3P fellowship.Peer reviewe

A structural characterization of the lignins from sugarcane (Saccharum spp. L) bagasse and straw

The structure of the lignins of sugarcane bagasse and straw was investigated. The lignins were characterized both in situ and in isolated preparations (Milled-Wood Lignin, MWL, and Cellulolytic Lignin, CEL) by Py-GC/MS and 2D-NMR. It was concluded that they are p-hydroxyphenyl-guaiacyl-syringyl lignins with associated p-coumarates and ferulates. 2D-NMR indicated that the main substructures present are β–O–4´-ethers, followed by β–5´ phenylcoumarans and with lower amounts of β–β´ resinols and β–1´ spirodienones.This study has been funded by the EU project LIGNODECO (KBBE-244362) and the Spanish project AGL2011-25379 (co-financed by FEDER funds). Jorge Rencoret thanks the CSIC for a JAE-DOC contract of the program “Junta para la Ampliación de Estudios” co-financed by Fondo Social Europeo (FSE). Funding provided by the Minas Gerais State Research Foundation (FAMEPIG) from the Brazilian National Council for Science and Technology Development (CNPq), and from the Coordination for the Improvement of Higher Education Personnel (CAPES) is greatly appreciated.N

Modification of the lignin structure during alkaline delignification of eucalyptus wood by kraft, soda-AQ, and soda-O2 cooking

11 páginas.-- 5 figuras.-- 4 tablas.-- 50 referencias.-- Supporting Information The general conditions for the kraft, soda-AQ, and soda-O2 alkaline cooking of eucalyptus feedstock, are shown in Table S1. The identification and relative molar abundance of the compounds identified in the Py-GC/MS of MWL from eucalyptus wood, and residual and black liquor lignins from kraft, soda-AQ,and soda-O2 pulping at different kappa numbers, are listed in Table S2. This material is available free of charge via the Internet at http://pubs.acs.org/doi/suppl/10.1021/ie401364dThe modification of the lignin structure of an eucalyptus feedstock during alkaline delignification by kraft, soda-AQ, and soda-O2 cooking processes has been investigated by different analytical techniques (size exclusion chromatography (SEC), pyrolysis gas chromatography-mass spectroscopy (Py-GC/MS), 1H-13C two-dimensional nuclear magnetic resonance (2D-NMR), and 31P NMR). The characteristics of the lignins were compared at different pulp kappa levels, and with the native lignin isolated from the wood. The structural differences between the kraft, soda-AQ, and soda-O2 residual lignins were more significant at earlier pulping stages. At the final stages, all the lignin characteristics were similar, with the exception of their phenolic content. Strong differences between lignins from pulps and cooking liquors were observed, including enrichment in guaiacyl units in pulp residual lignin and enrichment in syringyl units in black liquor lignin. A comparison of the alkaline cookings indicate that soda-O2 process produced higher lignin degradation and provided promising results as pretreatment for the deconstruction of eucalyptus feedstocks for subsequent use in lignocellulose biorefineries. © 2013 American Chemical Society.This study has been funded by the EU-Project LIGNODECO (No. KBBE-244362), the Spanish project (No. AGL2011-25379), and the CSIC project (No. 201040E075). Dr. Rencoret thanks the CSIC for a JAE-DOC contract in the program “Junta para la Ampliación de Estudios”, cofinanced by Fondo Social Europeo (FSE). Finally, we thank Suzano Papel e Celulose (Brazil) for providing the pulp and black liquor samples from the alkaline cooking experiments and the corresponding additional data.Peer Reviewe

Towards industrially-feasible delignification and pitch removal by treating paper pulp with Myceliophthora thermophila laccase and a phenolic mediator

The ability of two natural phenols to act as mediators of the recombinant Myceliophthora thermophila laccase (MtL) in eucalypt-pulp delignification was investigated. After alkaline peroxide extraction, the properties of the enzymatically-treated pulps improved with respect to the control. The pulp brightness increased (3.1 points) after the enzymatic treatment with MtL alone, but the highest improvements were obtained after the MtL treatment using syringaldehyde (4.7 points) and especially methyl syringate (8.3 points) as mediators. Likewise, a decrease in kappa number up to 2.7 points was obtained after the MtL–methyl syringate treatment, followed by decreases of 1.4 and 0.9 points after the treatments with MtL–syringaldehyde and MtL alone, respectively. On the other hand, removal of the main lipophilic extractives present in eucalypt pulp was observed after the above laccase–mediator treatments. Finally, the doses of both MtL and methyl syringate were reduced, and results compatible with industrial implementation were obtained.This study was funded by the BIORENEW and LIGNODECO EU projects (NMP2-CT-2006-026456 and KBBE-2009-3-244362, respectively) and the ELLE and RAPERO Spanish MICINN (co-financed by FEDER funds) projects AGL2008-00709 and BIO2008-01533, respectively).Peer reviewe

Analysis of a modern hybrid and an ancient sugarcane implicates a complex interplay of factors in affecting recalcitrance to cellulosic ethanol production

Abundant evidence exists to support a role for lignin as an important element in biomass recalcitrance. However, several independent studies have also shown that factors apart from lignin are also relevant and overall, the relative importance of different recalcitrance traits remains in dispute. In this study we used two genetically distant sugarcane genotypes, and performed a correlational study with the variation in anatomical parameters, cell wall composition, and recalcitrance factors between these genotypes. In addition we also tracked alterations in these characteristics in internodes at different stages of development. Significant differences in the development of the culm between the genotypes were associated with clear differential distributions of lignin content and composition that were not correlated with saccharification and fermentation yield. Given the strong influence of the environment on lignin content and composition, we hypothesized that sampling within a single plant could allow us to more easily interpret recalcitrance and changes in lignin biosynthesis than analysing variations between different genotypes with extensive changes in plant morphology and culm anatomy. The syringyl/guaiacyl (S/G) ratio was higher in the oldest internode of the modern genotype, but S/G ratio was not correlated with enzymatic hydrolysis yield nor fermentation efficiency. Curiously we observed a strong positive correlation between ferulate ester level and cellulose conversion efficiency. Together, these data support the hypothesis that biomass enzymatic hydrolysis recalcitrance is governed by a quantitative heritage rather than a single trait

A Robotic Hyperspectral Scanning Framework for Endoscopy

Gastrointestinal (GI) endoscopy is the gold-standard procedure for detection and treatment of dysplastic lesions and early stage GI cancers. Despite its proven effectiveness, its sensitivity remains suboptimal due to the subjective nature of the examination, which is substantially reliant on human-operator skills. For bowel cancer, colonoscopy can miss up to 22% of dysplastic lesions, with even higher miss rates for small (<5 mm diameter) and flat lesions. We propose a robotic hyperspectral (HS) scanning framework that aims to improve the sensitivity of GI endoscopy by automated scanning and real-time classification of wide tissue areas based on their HS features. A “hot-spot” map is generated to highlight dysplastic or cancerous lesions for further scrutiny or concurrent resection. The device works as an add-on accessory to any conventional endoscope, and to our knowledge, is the first of its kind. This paper focuses on characterising its optical resolution on rigid and deformable colon phantoms. We report for the first time 2D and 3D wide-area reconstruction of endoscopic HS data with sub-millimetre optical resolution. The current setup, compatible with the anatomical dimensions of the colon, could allow the identification of flat and small pre-cancerous lesions that are currently missed. The proposed framework will lay the foundations towards the next generation of augmented reality endoscopy while increasing its sensitivity and specificity

Polymerization of lignosulfonates by the laccase-HBT (1-hydroxybenzotriazole) system improves dispersibility

The ability of laccases from Trametes villosa (TvL), Myceliophthora thermophila (MtL), Trametes hirsuta (ThL) and Bacillus subtilis (BsL) to improve the dispersion properties of calcium lignosulfonates 398 in the presence of HBT as a mediator was investigated. Size exclusion chromatography showed an extensive increase in molecular weight of the samples incubated with TvL and ThL by 107% and 572% from 28400 Da after 17 h of incubation, respectively. Interestingly, FTIR spectroscopy, 13C NMR and Py-GC/MS analysis of the treated samples suggested no substantial changes in the aromatic signal of the lignosulfonates, a good indication of the ability of TvL/ThL-HBT systems to limit their effect on functional groups without degrading the lignin backbone. Further, the enzymatic treatments led to a general increase in the dispersion properties, indeed a welcome development for its application in polymer blends.Financial support from the BIORENEW EU-project (NMP2-CT-2006-26456), Austrian Academic Exchange Programme (OEAD) and the Spanish projects BIO2007-28720-E, BIO2008-01533, and AGL2008-00709 is acknowledged