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Lipids are a broad group of naturally-occurring molecules which includes fatty acids, steroids, terpenes and glycerides, among others, with important biological functions. However, their presence is undesirable in some cases such as in the pulp and paper manufacturing process where they cause the so-called pitch deposits. An enzymatic method to control pitch using a hydrolytic enzyme (lipase) to treat the pulp has been successfully applied in softwood mechanical pulping, preventing triglyceride deposition. However, lipases are not useful when pitch originates from other lipids, such as steroids and terpenes. Recently, several studies have shown the high potential of oxidative enzymes for the removal of pulp lipids regardless the pulping process and the raw material used, which will be summarized here. ; This work was supported by the Spanish projects AGL2008-00709 and BIO2007-28719-E, and the BIORENEW project of the European Union (contract NMP2-CT-2006-026456). INRA (Marseille, France) is acknowledged for the P. cinnabarinus strain, and Beldem (Andenne, Belgium) for laccase production. ENCE (Pontevedra, Spain), UPM-Kymmene (Valkeakoski, Finland), and CELESA (Tortosa, Spain), and UPC (Terrassa, Spain) are acknowledged for the eucalypt pulp, spruce TMP pulp and flax pulp samples, respectively. ; Peer reviewed

14 páginas, 7 figuras ; Pitch control is an important aspect in pulp and paper manufacture, and the first example where microbial biotechnology provided successful solutions in this industrial sector. Triglycerides cause deposits in softwood mechanical pulping, and both microbial and enzymatic products have been commercialized to be applied on wood and pulp, respectively. The former are based on colorless strains of sapstain fungi. The latter are improved lipases, including thermostable variants from directed evolution. These enzymes are among the additives of choice in pulping of high-resin-content softwoods. However, lipases are not useful when pitch originates from other lipids, such as steroids and terpenes, and the sapstain inocula are also only partially effective. In the search for stronger biocatalysts to degrade recalcitrant lipids, the potential of white-rot fungi and their enzymes has been demonstrated. When inocula of these fungi are used, wood treatment must be controlled to avoid cellulose degradation. However, the efficiency and selectivity of the laccase-mediator system permits its integration as an additional bleaching stage. A double benefit can be obtained from these treatments since pitch is controlled at the same time that residual lignin is removed facilitating the implementation of totally chlorine free pulp bleaching. ; This work was supported by the Spanish projects AGL2008-00709, BIO2005-03569 and BIO2008-01533, and the BIORENEW project of the European Union (contract NMP2-CT-2006-026456). ; Peer Reviewed

39 páginas.- 14 figuras.- 134 referencias ; 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 participating in oxidative radical reactions during the lignification process and becoming integrated into the lignin polymer in some plants. Various phenolic compounds have been found incorporated into the lignin, including phenolic compounds derived from the monolignol biosynthetic pathway (e.g., monolignol ester conjugates, caffeyl and 5-hydroxyconiferyl alcohols, hydroxycinnamaldehydes, among others). More fascinating still was the discovery in some plants of a series of phenolic compounds arising from other polyphenolic biosynthetic pathways, including flavonoids (tricin, dihydrotricin, naringenin, naringenin chalcone), hydroxystilbenes (resveratrol, piceatannol, and isorhapontigenin, and their O-glucosylated counterparts piceid, astringin, and isorhapontin), and ferulic acid amides (feruloyltyramine, and diferuloylputrescine), that are integrated into the lignin polymer. All of these discoveries indicate that the lignin structure is far more complex than previously thought, that the definition of lignin should not be restricted to a polymer derived solely from the three traditional monolignols, and that other unconventional lignin monomers must be considered, thus expanding the established definition of lignin. The overriding factor remains, however, that lignification, the process of polymerization to the lignin polymer, allows this compositional flexibility because it is a simple chemical process. © 2022 Elsevier Ltd ; JCdR, JRe and AG were funded by the Spanish Project AGL2017-83036-R and PID2020-118968RB-100 (financed by Ministerio de Ciencia e Innovación, MCIN, Agencia Estatal de Investigación, AEI, and European Regional Development Fund, ERDF, "A way of making Europe"), the Regional Andalusian Government (Consejerı ́a de Transformación Económica, Industria, Conocimiento y Universidades, Junta de Andalucıía, project P20-00017), and CSIC (project PIE 202040E185). JRa and HK were funded by the DOE Great Lakes Bioenergy Research Center (DOE Office of Science DE-SC0018409 ; Peer reviewed

12 páginas.- 6 figuras.- 2 tablas.- 56 referencias.-The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation ; 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 mass spectrometry using medium-length high-temperature capillary columns, which allowed the identification of a wide range of lipophilic compounds, from low molecular weight fatty acids to high molecular weight sterols esters, sterol glucosides, or triglycerides in the same chromatogram. The most abundant lipophilic compounds in rice straw were fatty acids, which accounted for up to 6,400 mg/kg (41.0% of all identified compounds), followed by free sterols (1,600 mg/kg; 10.2%), sterol glucosides (1,380 mg/kg; 8.8%), fatty alcohols (1,150 mg/kg; 7.4%), and triglycerides (1,140 mg/kg; 7.3%), along with lower amounts of high molecular weight wax esters (900 mg/kg; 5.8%), steroid ketones (900 mg/kg; 5.8%), monoglycerides (600 mg/kg; 3.8%), alkanes (400 mg/kg; 2.6%), diglycerides (380 mg/kg; 2.4%), sterol esters (380 mg/kg; 2.4%), tocopherols (340 mg/kg; 2.2%), and steroid hydrocarbons (60 mg/kg; 0.4%). This information is of great use for the valorization of rice straw to obtain valuable lipophilic compounds of interest for the nutraceutical, pharmaceutical, cosmetic, and chemical industries. Moreover, this knowledge is also useful for other industrial uses of rice straw, as in pulp and papermaking, since some lipophilic compounds are at the origin of the so-called pitch deposits during pulping. Copyright © 2022 Rosado, Marques, Rencoret, Gutiérrez and del Río. ; This work was 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 the Regional Andalusian Government, Consejería de Transformación Económica, Industria, Conocimiento y Universidades/FEDER (project P20-00017). MJR acknowledges the Spanish Ministry of Science, Innovation and Universities for a FPI fellowship (PRE2018-083267). ; Peer reviewed

7 pages, 5 figures, 1 table, 16 references. Instituto de Recursos Naturales y Agrobiología, CSIC, P.O. Box 1052, Avda. Reina Mercedes, 10, E-41080 Seville, Spain;E-mail address: delrio@irnase.csic.es ; An analytical procedure for the analysis of lipophilic extractives from wood and pitch deposits is described in this paper. It comprises a rapid gas chromatographic method that enables the analysis of a high number of samples in a short period of time. Short-length, high-temperature capillary columns with thin films and high temperature- programming rates were preferred for the rapid analysis of wood extractives since they enable elution and separation of compounds within a wide molecular mass range (from fatty acids to sterol esters and triglycerides) in the same chromatographic analysis in a short period of time. Several examples of analysis of extractives from pine and eucalypt woods and pitch deposits in an eucalypt kraft pulp, are shown. On the other hand, a simple fractionation method using solid-phase extraction (SPE) in aminopropyl cartridges is described for the preparative scale separation and fractionation of wood lipophilic extractives into major lipid classes. The SPE advantages include smaller sample and solvent requirements and ease of use compared to conventional solvent extraction techniques. ; This research has been supported by the Project "Wood Extractives in Pulp and Paper Manufacture: Technical and Environmental Implications and Biological Removal" (FAIR CT95-0560) of the European Union. ; Peer reviewed

10 páginas.- 4 figuras.- referencias.-Data Availability Statement: All data underlying this article are available in the main publication and in its Supplementary Materials online. ; Unspecific peroxygenases (UPOs), the extracellular enzymes capable of oxygenating a potpourri of aliphatic and aromatic substrates with a peroxide as co-substrate, come out with a new reaction: carbon-chain shortening during the conversion of fatty acids with the well-known UPOs from Coprinopsis cinerea (rCciUPO) and Cyclocybe (Agrocybe) aegerita (AaeUPO). Although a pathway (Cα-oxidation) for shortening the hydrocarbon chain of saturated fatty acids has already been reported for the UPO from Marasmius rotula (MroUPO), it turned out that rCciUPO and AaeUPO shorten the chain length of both saturated and unsaturated fatty acids in a different way. Thus, the reaction sequence does not necessarily start at the Cα-carbon (adjacent to the carboxyl group), as in the case of MroUPO, but proceeds through the subterminal (ω-1 and ω-2) carbons of the chain via several oxygenations. This new type of shortening leads to the formation of a dicarboxylic fatty acid reduced in size by two carbon atoms in the first step, which can subsequently be further shortened, carbon by carbon, by the UPO Cα-oxidation mechanism. View Full-Text ; This research was funded by BioBased Industries Joint Undertaking under the European Union's Horizon 2020 Research and Innovation Programme, grant number 792063 (SusBind project; https://susbind.eu; to A.G., Á.T.M. and M.H.), the PID2020-118968RB-100 project by the Spanish MCIN/AEI/ 10.13039/501100011033 to A.G., and the CSIC projects PIE-202040E185 (to A.G.) and PIE-202120E019 (to Á.T.M.). ; Peer reviewed

17 páginas.- 7 figuras.- 2 tablas.- 53 referencias.- Supplementary Materials: The following are available online (at https://www.mdpi.com/article/10.3390/antiox10121888/s1) ; Epoxide metabolites from n-3 and n-6 polyunsaturated fatty acids arouse interest thanks to their physiological and pharmacological activities. Their chemical synthesis has significant drawbacks, and enzymes emerge as an alternative with potentially higher selectivity and greener nature. Conversion of eleven eicosanoid, docosanoid, and other n-3/n-6 fatty acids into mono-epoxides by fungal unspecific peroxygenases (UPOs) is investigated, with emphasis on the Agrocybe aegerita (AaeUPO) and Collariella virescens (rCviUPO) enzymes. GC-MS revealed the strict regioselectivity of the n-3 and n-6 reactions with AaeUPO and rCviUPO, respectively, yielding 91%-quantitative conversion into mono-epoxides at the last double bond. Then, six of these mono-epoxides were obtained at mg-scale, purified and further structurally characterized by 1H, 13C and HMBC NMR. Moreover, chiral HPLC showed that the n-3 epoxides were also formed (by AaeUPO) with total S/R enantioselectivity (ee > 99%) while the n-6 epoxides (from rCviUPO reactions) were formed in nearly racemic mixtures. The high regio- and enantioselectivity of several of these reactions unveils the synthetic utility of fungal peroxygenases in fatty acid epoxidation. ; Funding: This research was funded by BioBased Industries Joint Undertaking under the European Union's Horizon 2020 Research and Innovation Programme, grant number 792063 (SusBind project; https://susbind.eu, accessed on 19 October 2021; to A.G., A.T.M. and M.H.), the BIO2017-86559-R and PID2020-118968RB-100 projects of the Spanish Ministry of Science & Innovation (co-financed by FEDER funds) to A.T.M. and A.G., respectively; the CSIC projects PIE-202040E185 (to A.G.) and PIE-202120E019 (to A.T.M.); and the CSIC SusPlast platform (to A.T.M.). ; Peer reviewed

Lipophilic extractives from wood and nonwood fibers exert a negative impact in pulp and paper manufacture causing pitch deposits. We have shown the effectiveness of the laccase-mediator system in removing pulp lipids regardless the pulping process and the raw material used. The enzymatic treatments were performed using a fungal laccase from Pycnoporus cinnabarinus and 1-hydroxybenzotriazole (HBT) as mediator. Gas chromatography-mass spectrometry of extracts from the enzymatically-treated pulps revealed that most of the lipids (including free and conjugated sitosterol, fatty and resin acids, and triglycerides) were removed. Improved pulp brightness and decreased kappa number were also observed. Then, the chemistry of the reactions of lipophilic extractives with laccase-HBT was studied using model alkanes, fatty alcohols, fatty acids, resin acids, free sterols, sterol esters and triglycerides. The laccase alone modified some unsaturated lipids, however, the most rapid and extensive removal was obtained in the presence of mediator. Different degradation patterns were observed, and several oxidation products were identified. Lignin related phenols were tested as alternative to synthetic mediators for lipid removal from eucalypt pulp. Over 90% removal of free and conjugated sitosterol, similar to that attained with HBT, was obtained with some of them. A positive effect on pulp brightness and kappa number was also obtained, especially after a peroxide stage. ; This work was supported by the Spanish projects AGL2008-00709, BIO2007-28719-E and BIO2008-01533, and the BIORENEW project of the European Union (contract NMP2-CT-2006-026456). INRA (Marseille, France) is acknowledged for the P. cinnabarinus strain, and Beldem (Andenne, Belgium) for laccase production. ENCE (Pontevedra, Spain), UPM Kymmene (Valkeakoski, Finland), and CELESA (Tortosa, Spain), and UPC (Terrassa, Spain) are acknowledged for the eucalypt pulp, spruce TMP pulp and flax pulp samples, respectively. ; Peer reviewed

12 páginas.- 2 figuras.- 2 tablas.- 55 referencias.-Supplementary Materials: The following supporting information can be downloaded at: https:www.mdpi.com/article/10.3390/antiox11030522/s1 ; Terminal alkenes are among the most attractive starting materials for the synthesis of epoxides, which are essential and versatile intermediate building blocks for the pharmaceutical, fla-voring, and polymer industries. Previous research on alkene epoxidation has focused on the use of several oxidizing agents and/or different enzymes, including cytochrome P450 monooxygenases, as well as microbial whole-cell catalysts that have several drawbacks. Alternatively, we explored the ability of unspecific peroxygenases (UPOs) to selectively epoxidize terminal alkenes. UPOs are attractive biocatalysts because they are robust extracellular enzymes and only require H2O2 as cosub-strate. Here, we show how several UPOs, such as those from Cyclocybe (Agrocybe) aegerita (AaeUPO), Marasmius rotula (MroUPO), Coprinopsis cinerea (rCciUPO), Humicola insolens (rHinUPO), and Daldinia caldariorum (rDcaUPO), are able to catalyze the epoxidation of long-chain terminal alkenes (from C12:1 to C20:1) after an initial optimization of several reaction parameters (cosolvent, cosub-strate, and pH). In addition to terminal epoxides, alkenols and other hydroxylated derivatives of the alkenes were formed. Although all UPOs were able to convert and epoxidize the alkenes, nota-ble differences were observed between them, with rCciUPO being responsible for the highest sub-strate turnover and MroUPO being the most selective with respect to terminal epoxidation. The potential of peroxygenases for epoxidizing long-chain terminal alkenes represents an interesting and green alternative to the existing synthesis technologies. © 2022 by the authors. Licensee MDPI, Basel, Switzerland ; This research was funded by BioBased Industries Joint Undertaking under the European Union's Horizon 2020 Research and Innovation Programme, grant number 792063 (SusBind project; https://susbind.eu, accessed on 1 February 2022; to A.G., A.T.M. and M.H.); the PID2020-118968RB-100 project of the Spanish MCIN/AEI/10.13039/501100011033 to A.G.; the CSIC projects PIE-202040E185 (to A.G.) and PIE-202120E019 (to A.T.M.); the CSIC SusPlast platform (to A.T.M.); and the CSIC program for the Spanish Recovery, Transformation and Resilience Plan funded by the Recovery and Resilience Facility of the European Union, established by the Regulation (EU) 2020/2094 ; Peer reviewed

19 páginas.- 8 figuras.- 5 tablas.- 174 referencias ; Selective oxyfunctionalizations of aliphatic compounds are difficult chemical reactions, where enzymes can play an important role due to their stereo- and regio-selectivity and operation under mild reaction conditions. P450 monooxygenases are well-known biocatalysts that mediate oxyfunctionalization reactions in different living organisms (from bacteria to humans). Unspecific peroxygenases (UPOs), discovered in fungi, have arisen as "dream biocatalysts" of great biotechnological interest because they catalyze the oxyfunctionalization of aliphatic and aromatic compounds, avoiding the necessity of expensive cofactors and regeneration systems, and only depending on H2O2 for their catalysis. Here, we summarize recent advances in aliphatic oxyfunctionalization reactions by UPOs, as well as the molecular determinants of the enzyme structures responsible for their activities, emphasizing the differences found between well-known P450s and the novel fungal peroxygenases. © 2021 The Authors ; This work has 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 (Development and pilot production of sustainable binder systems for wood based panels, https://susbind.eu), and from the Spanish Ministry of Industry, Economy and Competitiveness project BIO2017-86559-R, cofinanced by FEDER funds, and the Consejo Superior de Investigaciones Científicas projects PIE-201620E081 and PIE-202040E185 ; Peer reviewed

Instituto de Recursos Naturales y Agrobiología, CSIC, Reina Mercedes 10, P.O. Box 1052, E-41080 Seville, Spain, Centro de Investigaciones Biológicas, CSIC, Velázquez 144, E-28006 Madrid, Spain, ENCE, Centro de Investigación y Tecnología, Ctra. Campañó s/n, E-36157 Pontevedra, Spain, and Centre Technique du Papier, Domaine Universitaire, P.O. Box 251, Cedex 9, F-38044 Grenoble, France ; Modern environmentally sound trends in manufacturing of bleached paper pulp involve development of totally chlorine free (TCF) bleaching and zero liquid effluent (ZLE)processes. Lipophilic extractives are among the most problematic wood constituents for both TCF and ZLE processes, since they tend to accumulate in circuits resulting in new manufacturing ("pitch" deposits) and environmental troubles. The extractive-degrading fungi Bjerkandera adusta, Phlebia radiata, Pleurotus pulmonarius and Poria subvermispora were assayed to remove these compounds from Eucalyptus globulus wood using solid-state fermentation conditions. The pretreated chips were subjected to laboratory kraft pulping to assess the effectiveness of the treatment. Evaluation of extractive removal was carried out by gas chromatography-mass spectrometry of extracts from the pretreated wood and the pulps and black liquors after cooking. As a result of the fungal pretreatment, up to 75% decreased levels of problematic compounds (including free and esterified sitosterol) were found in pulps and liquors. Moreover, a significant reduction of potential acute toxicity was found in black liquors from wood pretreated with three of the fungi. The biopulps were TCF-bleached, refined and handsheet properties evaluated to select the most advantageous fungi from the point of view of their industrial applicability in environmentally sound pulp manufacturing processes. ; This study has been partially supported by the European Union (contract FAIR-CT95-0560, "Wood extractives in pulp and paper manufacture: Technical and environmental implications and biological removal") and by the Spanish Biotechnology Program. ; Peer reviewed

14 páginas.-- 10 figuras.-- 1 tabla.-- 46 referencias.-- Author's Choice—Final version free via Creative Commons CC-BY license. ; Versatile peroxidase (VP) is a high redox-potential peroxidase of biotechnological interest that is able to oxidize phenolic and non-phenolic aromatics, Mn2 , and different dyes. The ability of VP from Pleurotus eryngii to oxidize water-soluble lignins (softwood and hardwood lignosulfonates) is demonstrated here by a combination of directed mutagenesis and spectroscopic techniques, among others. In addition, direct electron transfer between the peroxidase and the lignin macromolecule was kinetically characterized using stopped-flow spectrophotometry. VP variants were used to show that this reaction strongly depends on the presence of a solvent-exposed tryptophan residue (Trp-164). Moreover, the tryptophanyl radical detected by EPR spectroscopy of H2O2-activated VP (being absent from the W164S variant) was identified as catalytically active because it was reduced during lignosulfonate oxidation, resulting in the appearance of a lignin radical. The decrease of lignin fluorescence (excitation at 355 nm/emission at 400 nm) during VP treatment under steady-state conditions was accompanied by a decrease of the lignin (aromatic nuclei and side chains) signals in one-dimensional and two-dimensional NMR spectra, confirming the ligninolytic capabilities of the enzyme. Simultaneously, size-exclusion chromatography showed an increase of the molecular mass of the modified residual lignin, especially for the (low molecular mass) hardwood lignosulfonate, revealing that the oxidation products tend to recondense during the VP treatment. Finally, mutagenesis of selected residues neighboring Trp-164 resulted in improved apparent second-order rate constants for lignosulfonate reactions, revealing that changes in its protein environment (modifying the net negative charge and/or substrate accessibility/binding) can modulate the reactivity of the catalytic tryptophan ; This work was supported by the INDOX (KBBE-2013-613549) European Union project, the HIPOP (BIO2011-26694), NOESIS (BIO2014-56388-R), and BIORENZYMERY (AGL2014-53730-R) projects of the Spanish Ministry of Economy and Competitiveness (MINECO) co-financed by FEDER funds, and the PRIN 2009-STNWX3 project of the Italian Ministry of Education, Universities and Research (MIUR). ; Supported by an FPI Fellowship of the Spanish MINECO.-- Supported by a contract of the CSIC project 201440E097.-- Supported by a Ramón y Cajal contract of the Spanish MINECO ; Peer reviewed

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. ; Peer reviewed

12 páginas.- 6 figuras.- 1 tabla.- 84 referencias.- The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acscatal.0c03165 ; Epoxidation of unsaturated fatty acids by unspecific peroxygenases (UPOs) of the best-known long-UPO subfamily, including the Agrocybe aegerita (AaeUPO) and Coprinopsis cinerea enzymes, is reported here. To understand the different oxygenation patterns by members of the long-UPO and short-UPO subfamilies, the latter represented by the Marasmius rotula enzyme (MroUPO), fatty-acid diffusion into their heme pockets was simulated with the adaptive PELE software. Computational results shed light on the inability of AaeUPO to epoxidize oleic acid (C18:1), opposed to MroUPO, due to steric hindrances to harbor (with a good interaction energy) the substrate with the Δ9 C10 atom at a catalytically relevant distance (99%) formation of cis,cis-15,16-epoxyoctadeca-9,12-dienoic acid. The nearly complete conversion of α-linolenic acid by the two enzymes was transferred to a small preparative scale, the yield of purified product was estimated, its chemical structure analyzed by NMR, and more interestingly, stereoselective production of the 15(R),16(S) enantiomer (80-83% ee) assessed by chiral HPLC. This enzymatic synthesis overcomes the unspecificity of chemical epoxidation where the reaction cannot be restricted to the formation of monoepoxides as found during m-perchlorobenzoic acid oxidation of α-linolenic acid. Moreover, the variant was able to produce the unsaturated dicarboxylic fatty acid, together with subterminal oxygenation products, during partial conversion of oleic acid. These two noteworthy reactions had not been reported for any UPO described to date. © 2020 American Chemical Society. All rights reserved. ; This work has 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 ("Development and pilot production of sustainable binder systems for wood based panels", https://susbind.eu ), the CTQ2016-79138-R and BIO2017-86559-R projects of Spanish MINECO, the Secretaria d'Universitats i Recerca of Generalitat de Catalunya, and the European Social Fund (ESF-2019-FI-B-00154). The authors thank Novozymes A/S for supplying r CciUPO. MM acknowledges a Catalan Government doctoral grant. ; Peer reviewed

19 páginas.- 9 figuras.- referencias ; 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 physico-chemical barriers remain understudied, while being a key component of resistance. Here we use a combination of histological and live-imaging techniques, together with spectroscopy and gene expression analysis to understand the nature of R. solanacearum-induced formation of vascular coatings in resistant tomato. We describe that resistant tomato specifically responds to infection by assembling a vascular structural barrier formed by a ligno-suberin coating and tyramine-derived hydroxycinnamic acid amides. Further, we show that overexpressing genes of the ligno-suberin pathway in a commercial susceptible variety of tomato restricts R. solanacearum movement inside the plant and slows disease progression, enhancing resistance to the pathogen. We propose that the induced barrier in resistant plants does not only restrict the movement of the pathogen, but may also prevent cell wall degradation by the pathogen and confer anti-microbial properties, effectively contributing to resistance. ; Research is funded by MCIN/AEI/10.13039/501100011033 (NSC, MV), MCIN/AEI/PID2019-110330GB-C21 (MF, OS), MCIN/AEI/PID2020-118968RBI00 (JR), through the 'Severo Ochoa Programme for Centres of Excellence in R&D' (SEV-2015-0533, CEX2019-000917 and CEX2019-000902-S funded by MCIN/AEI/ 10.13039/501100011033), and by the Spanish National Research Council (CISC) pie-201620E081 (JR, AG) and the Generalitat de Catalunya (2017SGR765 grant). AK is the recipient of a Netaji Subhas – Indian Council of Agricultural Research International Fellowship. SS acknowledges financial support from DOC-FAM, European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement no. 754397. This work was also supported by the CERCA Program/Generalitat de Catalunya. ; Peer reviewed