Jorge Rencoret

Institute of Natural Resources and Agrobiology of Seville (IRNAS-CSIC)

Understanding the responses of olive trees to drought stress is crucial for improving cultivation and developing drought-tolerant varieties. Water transport and storage within the plant is a key factor in drought-tolerance strategies. Water management can be based on a variety of factors such as stomatal control, osmoprotectant molecules, proteins...

Lignins released in the black liquors of kraft pulp mills are an underutilised source of aromatics. Due to their phenol oxidase activity, laccases from ligninolytic fungi are suitable biocatalysts to depolymerise kraft lignins, which are characterised by their elevated phenolic content. However, the alkaline conditions necessary to solubilise kraft...

Plant vascular pathogens use different ways to reach the xylem vessels and cause devastating diseases in plants. Resistant and tolerant plants have evolved various defense mechanisms against vascular pathogens. Inducible physico-chemical structures, such as the formation of tyloses and wall reinforcements with phenolic polymers, are very effective...

The differences in the composition and structure of the lignins from straws of different oat (Avena sativa L.) varieties, planted in two seasons (winter and spring), were studied in detail by different analytical techniques such as pyrolysis coupled to gas chromatography-mass spectrometry (Py-GC/MS), two-dimensional nuclear magnetic resonance (2D-N...

The pruning of sweet orange trees (Citrus sinensis) generates large amounts of lignocellulosic residue. Orange tree pruning (OTP) residue presents a significant lignin content (21.2%). However, there are no previous studies describing the structure of the native lignin in OTPs. In the present work, the “milled-wood lignin” (MWL) was extracted from...

Hydroxystilbenes 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 insigh...

As ever more component monomers are discovered, lignin can no longer be regarded as deriving from just the three canonical monolignols. Pathway intermediates such as the hydroxycinnamaldehydes and their derived hydroxybenzaldehydes, and additional products of truncated biosynthesis such as caffeyl and 5‐hydroxyconiferyl alcohols, are now establishe...

Papyrus (Cyperus papyrus L.) is a sedge plant with a high rate of biomass productivity that represents an interesting raw material to produce chemicals, materials and fuels, which are currently still obtained from fossil resources, in the context of a lignocellulosic biorefinery. In this work, the content and chemical composition of the lipids pres...

Agro-industrial residues were used as a successful, cheap and renewable substrate, capable of increasing activity of ligninolytic enzymes for further use in melanin degradation assays to develop inputs for the treatment of skin hyperpigmentation. The analysis of melanin degradation was performed in a quantitative and qualitative way. The enzymatic...

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,...

Enzymes can substitute harsh and energy-demanding chemical treatments for production of bio-based building blocks and products from wood processing. However, their properties need to be adapted to the extreme operation conditions (such as high T and pH) commonly used by these industries. Here, we summarize the main results obtained during the WoodZ...

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 t...

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 c...

Diferuloylputrescine has been found in a variety of plant species, and recent work has provided evidence of its covalent bonding into lignin. Results from nuclear magnetic resonance spectroscopy revealed the presence of bonding patterns consistent with homo-coupling of diferuloylputrescine and the possibility of cross-coupling with lignin. In the p...

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, an...

Rice (Oryza sativa L.) straw is a highly abundant, widely available, and low cost agricultural waste that can be used as a source to extract valuable phytochemicals of industrial interest. Hence, in the present work, the chemical composition of the lipophilic compounds present in rice straw was thoroughly characterized by gas chromatography and mas...

Lignin is largely produced by the oxidative radical coupling of the three monolignols, p-coumaryl, coniferyl, and sinapyl alcohols, which form the p-hydroxyphenyl, guaiacyl, and syringyl lignin units in the lignin polymer. However, it is increasingly appreciated that other “unconventional” phenolic compounds can also behave as lignin monomers parti...

Tomato varieties resistant to the bacterial wilt pathogen Ralstonia solanacearum have the ability to restrict bacterial movement in the plant. Inducible vascular cell wall reinforcements seem to play a key role in confining R. solanacearum into the xylem vasculature of resistant tomato. However, the type of compounds involved in such vascular physi...

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 part...

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 nar...

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 struc...

Lignin biodegradation has been extensively studied in white-rot fungi, which largely belong to order Polyporales. Among the enzymes that wood-rotting polypores secrete, lignin peroxidases (LiPs) have been labeled as the most efficient. Here, we characterize a similar enzyme (ApeLiP) from a fungus of the order Agaricales (with ~13,000 described spec...

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...

The soil borne pathogen Ralstonia solanacearum is the causing agent of bacterial wilt, a devastating disease affecting major agricultural crops. R. solanacearum enters plants through the roots and reaches the vasculature, causing rapid wilting. We recently showed that tomato varieties resistant to bacterial wilt restrict bacterial movement in the p...

Pleurotus eryngii is a grassland-inhabiting fungus of biotechnological interest due to its ability to colonize non-woody lignocellulosic material. Genomic, transcriptomic, exoproteomic, and metabolomic analyses were combined to explain the enzymatic aspects underlaying wheat–straw transformation. Up-regulated and constitutive glycoside–hydrolases,...

Lignin is a phenylpropanoid polymer derived essentially from the oxidative radical coupling of three p‐hydroxycinnamyl alcohols, the so‐called monolignols: p‐coumaryl, coniferyl, and sinapyl alcohols. Several other phenolic compounds, all originating from the shikimate‐derived monolignol biosynthetic pathway, have been found to behave as lignin mon...

The 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 throu...

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 ligni...

Plant lignocellulosic biomass, mostly composed of polysaccharide-rich secondary cell walls (SCWs), provides fermentable sugars that may be used to produce biofuels and biomaterials. However, the complex chemical composition and physical structure of SCWs hinder efficient processing of plant biomass. Understanding the molecular mechanisms underlying...

Lignins from different parts of the seagrass Posidonia oceanica –namely sheaths, rhizomes, and roots– as well as from fibrous balls from P. oceanica detritus were isolated and thoroughly characterized by Pyrolysis coupled with Gas Chromatography/Mass Spectrometry (Py-GC/MS), Derivatization Followed by Reductive Cleavage (DFRC), two-dimensional Nucl...

This paper summarizes and compares computational results for the thermodynamics of bond dissociation, coupling, and rearomatization for a number of non-canonical lignin monomer-lignol combinations that have been found to occur experimentally. The non-canonical lignin monomers discussed are tricin, caffeyl alcohol and 5-hydroxyconiferyl alcohol, and...

Eucalyptus 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, formic and acetic acids. The reactions were performed under diverse operational conditions (180 or 190ºC, reaction...

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/...

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. Cel...

Cereal brans constitute an unexploited source of valuable cell wall polysaccharides and phenolics. Sequential subcritical water extraction (SWE) of wheat, barley and rye bran enables the isolation of cell wall polysaccharides with targeted molecular structures. The extracts switched from glucan-rich to higher contents of feruloylated arabinoxylan (...

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 compo...

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...

Novel laccases have promising and valuable applications in biorefineries. This investigation documents, for the first time, the potential of depolymerising and repolymerising lignin by the secretome, rich in laccases, from a newly isolated white-rot basidiomycete Marasmiellus palmivorus VE111, for further saccharification and ethanolic fermentation...

A comparison of sequenced Agaricomycotina genomes suggests that efficient degradation of wood lignin was associated with the appearance of secreted peroxidases with a solvent-exposed catalytic tryptophan. This hypothesis is experimentally demonstrated here by resurrecting ancestral fungal peroxidases, after sequence reconstruction from genomes of e...

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...

It was demonstrated for the first time that a laccase-based enzymatic pretreatment is able to delignify fast-growing paulownia species. The treatment was performed with a commercial low-redox potential laccase isolated from Myceliophthora thermophila (Apinis) Oorschot and methyl syringate (MeS) as a natural phenolic mediator. Up to 24% lignin remov...

Olive tree pruning (OTP) is an abundant and inexpensive agricultural lignocellulosic residue that is an interesting feedstock for producing bioethanol and other bio-products in the context of lignocellulosic biorefineries. However, the presence of lignin in OTP hinders the transformation processes as it limits the access to cell wall polysaccharide...

Tricin [5,7-dihydroxy-2-(4-hydroxy-3,5-dimethoxyphenyl)-4H-chromen-4-one] is a flavone that has been found to be incorporated in grass lignin polymers via 4′–O–β coupling. Herein, we investigated the tricin-lignin structure using nuclear magnetic resonance (NMR) methods by comparing the 1H–13C heteronuclear correlation (HSQC) NMR spectra of the iso...

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 exp...

Background Preparing multiple products from lignocellulosic biomass feedstock enhances the profit and sustainability of future biorefineries. Grasses are suitable feedstocks for biorefineries as they permit a variety of possible by-products due to their particular chemical characteristics and morphology. Elucidating the fate of p-hydroxycinnamates...

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 subs...

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 °...

A recent paper in Organic Geochemistry entitled "Radi-cally different lignin composition in Posidonia species may link to differences in organic carbon sequestration capacity" discusses the remarkable difference in lignin chemistry between two kinds of "Neptune grass", i.e. Posidonia oceanica and Posidonia australis. Analytical Pyrolysis Letters AP...

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 wi...

Background: New biorefinery concepts are necessary to drive industrial use of lignocellulose biomass components. Xylan recovery before enzymatic hydrolysis of the glucan component is a way to add value to the hemicellulose fraction, which can be used in papermaking, pharmaceutical, and food industries. Hemicellulose removal can also facilitate sub...

Protein polymers exist in every plant cell wall preparation, and they interfere with lignin characterization and quantification. Here we report the structural characterization of the residual protein peaks in 2D NMR spectra in corn cob and kenaf samples, and note that aromatic amino acids are ubiquitous and evident in spectra from various other pla...

Wheat straw and oak wood chips were incubated with Ceriporiopsis subvermispora and Lentinula edodes for 8 weeks. Samples from the fungal treated substrates were collected every week for chemical characterization. L. edodes continuously grew during the 8 weeks on both wheat straw and oak wood chips, as determined by the ergosterol mass fraction of t...

Sugarcane bagasse and straw, two major agro-industrial by-products 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 polysacc...

Lignin, the plant cell wall polymer that binds fibers together but makes processing difficult, is traditionally formed from three monomers, the so-called monolignols (p-coumaryl, coniferyl, and sinapyl alcohols). Recently we discovered, in grass lignins, a phenolic monomer that falls outside the canonical lignin biosynthetic pathway, the flavone tr...

Fungi produce heme-containing peroxidases and peroxygenases, flavin-containing oxidases and dehydrogenases, and different copper-containing oxidoreductases involved in the biodegradation of lignin and other recalcitrant compounds. Heme peroxidases comprise the classical ligninolytic peroxidases and the new dye-decolorizing peroxidases, while heme p...

Lignin, a multi-functional major biomass component, has a prominent potential as feedstock for being converted into high value-added products. Lignin is available in high amounts as side streams during cellulosic ethanol production and, within the biorefinery context, it is important to assess its structural characteristics in order to explore its...

Commercial furfural, an important platform chemical, is produced from acid hydrolysis of lignocellulosic biomass. The manufacturing processes are inherently inefficient, and so it is necessary to value add to substantial amounts of residue obtained. The structural features of bagasse furfural residue and the lignins extracted from it by three NaOH...

Lignin, a cross-linked macromolecule of hydrophobic aromatic structure, provides additional rigidity to a plant cell wall. Although it is an integral part of the plant cell, presence of lignin considerably reduces the quality of the fiber of fiber-yielding plants. Decreasing lignin in such plants holds significant commercial and environmental poten...

Caffeoyl Coenzyme A 3-O-Methyltransferase (CCoAOMT) and Caffeic acid-O-Methyltransferase (COMT) are key enzymes in the biosynthesis of coniferyl and sinapyl alcohols, the precursors of guaiacyl (G) and syringyl (S) lignin subunits. The function of these enzymes was characterised in single and double mutant maize plants. In this work, we determined...

Wood and forest residues have structural components like hemicelluloses and lignin that limited the accessibility of the enzymes or microorganism to the cellulose further fermentation to ethanol. In this study, Eucalyptus globulus wood chips were submitted to autohydrolysis pretreatment at different severity conditions. Goal: The main purpose was t...

The composition and structure of lignin in different tissues—phellem (cork), phloem and xylem (wood)—of Quercus suber was studied. Whole cell walls and their respective isolated milled lignins were analyzed by pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS), two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) and...

Background The present work investigated the influence of lignin content and composition in the fungal treatment of lignocellulosic biomass in order to improve rumen degradability. Wheat straw and wood chips, differing in lignin composition, were treated with Lentinula edodes for 0, 2, 4, 8 and 12 wk and the changes occurring during fungal degradat...

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 solubil...