Suchergebnisse

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

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