Hydrocarbons are essential base chemicals as energy carriers and starting materials for chemical manufacture. So-called fatty acid photodecarboxylases (FAPs) represent interesting catalysts for the conversion of natural fatty acids into hydrocarbons thereby giving access to alkanes from renewable feedstock. Today, however, only few FAPs are known. In the current study we report a new FAP from the marine organism Micractinium conductrix (McFAP). In contrast to currently known FAPs McFAP exhibits high catalytic activity towards short and medium fatty acids. Recombinant expression and basic biochemical characterisation of this new member of the FAP family is reported.

Unspecific peroxygenases (UPOs) represent an emerging class of catalysts for the selective oxyfunctionalisation of C–H- and C = C groups. Until now, only a few UPOs have been characterised. In this study, we report a new peroxygenase identified from the Unspecific Peroxygenase Database. The UPO from Agaricus bisporus var. bisporus (AbvbUPO) has been heterologously expressed in Aspergillus niger and initially characterised with respect to its basic biochemical features. Furthermore, its catalytic properties were evaluated with enzymatic cascade reactions of choline oxidase (AnChOx) and AbvbUPO, which the AnChOx provided H₂O₂ necessary via reductive activation of oxygen in situ. Three types of oxyfunctionalizations, such as hydroxylation of ethylbenzene, epoxidations of styrene and cyclohexene, sulfoxidations of methyl phenyl sulfide and phenyl vinyl sulfide, were successfully achieved. We also investigated the activity of AbvbUPO on fatty acids in some more detail. The experimental results show that Under the above conditions, AbvbUPO had the higher activity for cyclohexene epoxidation and sulfonation of sulfide substrates. The concentration of epoxy cyclohexane was 2.91 mM, and the concentration of methyl phenyl sulfoxide was 3.69 mM. The regioselectivity of AbvbUPO was ω-1 bonds position of linear saturated fatty acid. All in all, AbvbUPO exhibits some interesting differences which may put the basis for further understanding of the factors determining peroxygenase selectivity.

Unspecific peroxygenases (UPOs, EC 1.11.2.1) are promising oxyfunctionalization catalysts because of their unique stereoselectivity. However, so far only a few UPOs have been reported. In this study, gene mining was used to identify a gene from Galerina marginata that coded for a novel UPO (GmaUPO). GmaUPO was expressed in Pichia pastoris X-33 by scale-up fermentation (the UPO activity of the culture supernatant was 118 U/L). GmaUPO exhibited a molecular weight of 40 kDa and exhibited highest activity at 35°C and pH 9, respectively. Furthermore, GmaUPO was demonstrated to catalyze the epoxidation, sulfoxidation, and hydroxylation of common substrates, particularly fatty acids such as tridecanoic acid. The molecular basis for GmaUPO regioselectivity for fatty acid hydroxylation was explored by molecular modelling. The regioselectivity was mostly governed by the architecture of the enzyme's active site.

Invited for this month's cover is the group of Prof. Dr. Frank Hollmann at Delft University of Technology in the Netherlands. The Front Cover shows the vanadium-dependent haloperoxidase from the marine organism Curcuvaria inaequalis, which efficiently activates halides as hypohalites that can then initiate spontaneous halo-lactonization and halo-etherification reactions. The Communication itself is available at 10.1002/cssc.201902240.

A chemoenzymatic method for the halocyclization of unsaturated alcohols and acids by using the robust V-dependent chloroperoxidase from Curvularia inaequalis (CiVCPO) as catalyst has been developed for the in situ generation of hypohalites. A broad range of halolactones and cyclic haloethers are formed with excellent performance of the biocatalyst.

H ₂ O ₂ , is an attractive oxidant for synthetic chemistry, especially if activated as percarboxylic acid. H ₂ O ₂ , however, is also a potent inactivator of enzymes. Protein engineering efforts to improve enzyme resistance against H ₂ O ₂ in the past have mostly focused on tedious probabilistic directed evolution approaches. Here we demonstrate that a rational approach combining multiscale MD simulations and Born-Oppenheimer ab initio QM/MM MD simulations is an efficient approach to rapidly identify improved enzyme variants. Thus, the lipase from Penicillium camembertii was redesigned with a single mutation (I260R), leading to drastic improvements in H ₂ O ₂ resistance while maintaining the catalytic activity. Also the extension of this methodology to other enzymes is demonstrated.

Peroxygenases are promising catalysts for preparative oxyfunctionalization chemistry as they combine the versatility of P450 monooxygenases with simplicity of cofactor-independent enzymes. Though many interesting applications have been reported, today ‘we have only scratched the surface’ and significant efforts are necessary to solve issues related to selectivity of the wild type enzymes and low product titers. For this, further elucidation of the vast natural diversity as well as protein and reaction engineering approaches are discussed.

Deep eutectic solvents act as surfactants in biphasic (hydrophobic/aqueous) reaction mixtures enabling higher interfacial surface areas at lower mechanical stress as compared to simple emulsions. Exploiting this effect the rate of a chemoenzymatic epoxidation reaction was increased more than six-fold.