Selective Epoxidation of Fatty Acids and Fatty Acid Methyl Esters by Fungal Peroxygenases

Abstract

Recently discovered fungal unspecific peroxygenases from Marasmius rotula and Chaetomium globosum catalyze the epoxidation of unsaturated fatty acids (FA) and FA methyl esters (FAME), unlike the well-known peroxygenases from Agrocybe aegerita and Coprinopsis cinerea. Reactions of a series of unsaturated FA and FAME with cis-configuration revealed high (up to 100 %) substrate conversion and selectivity towards epoxidation, although some significant differences were observed between enzymes and substrates with the best results being obtained with the C. globosum enzyme. This and the M. rotula peroxygenase appear as promising biocatalysts for the environmentally-friendly production of reactive FA epoxides given their self-sufficient monooxygenase activity and the high conversion rate and epoxidation selectivity.

Two New Unspecific Peroxygenases from Heterologous Expression of Fungal Genes in Escherichia coli

“…In addition to the above-mentioned aromatics, UPOs are also active on aliphatic substrates. This includes unsaturated fatty acids, as recently shown for the M. rotula UPO (12,45). In a preliminary analysis, the oxyfunctionalization pattern for the latter enzyme was compared with those obtained for the two new UPOs using oleic acid as the substrate.…”

“…The involvement of several heme environment and channel residues (namely, Phe69, Phe76, Phe121, Phe191, and Phe199) in oxidation of polycyclic and other aromatic substrates by this UPO was suggested when its crystal structure was reported for the first time (31). Inversely, the preference of the M. rotula UPO for aliphatic compounds, compared with the A. aegerita UPO preferring aromatics (3,(45)(46)(47), could be related to the much lower number of phenylalanine residues at its heme pocket and access channel (only 9 phenylalanines in the whole protein structure) ( Fig. 6D).…”

“…Interestingly, the three enzymes showed different oxyfunctionalization patterns. While a mixture of epoxide and hydroxy-epoxides (with hydroxy groups at -7, -1, and other positions) had been reported for the wild (45) and recombinant (12) M. rotula UPO, nearly full conversion with the new UPOs yields as a main product either epoxide by the C. virescens UPO or a variety of subterminal hydroxy/keto derivatives by the D. caldariorum UPO. A complete study of unsaturated fatty acid epoxidation by the C. virescens UPO has been recently reported (54).…”

Fatty acid epoxidation byCollariella virescensperoxygenase and heme-channel variants

“…15,16 In a similar way, E. coli expression paves the way for investigating structural-functional relationships and engineering UPOs, as recently shown 17 for the previously described 6 UPO of M. rotula that catalyzes several unique reactions. 8,[18][19][20][21][22][23] Here, we report C. virescens UPO (produced in E. coli) as a new model enzyme for epoxidation reactions. Epoxides are among the most widely used intermediates in organic synthesis as precursors to complex molecules.…”

Selective synthesis of 4-hydroxyisophorone and 4-ketoisophorone by fungal peroxygenases

“…The spectrum of reactions catalyzed by these enzymes is steadily increasing and includes oxygenations of both aromatic 19,20 and aliphatic compounds, [21][22][23][24] fatty acids epoxidation 25 and chain-shortening, 26 and also reactions of rather complex and bulky substrates like steroids, 27,28 and secosteroids 29,30 that are subject to epoxidation, side-chain hydroxylation or side-chain removal.…”