The monoterpene citronellol often represents the substrate for the synthesis of other natural products and fragrances bearing α-branched tetrahydropyran moieties. In this contribution, we developed a process that combines in one-pot condition photocatalytic Schenck-ene reaction and biocatalytic halocyclization to synthesize enantiopure α-branched tetrahydropyrans starting from natural monoterpene citronellol. The reaction pathway of the enzymatic haloetherification, studied by combining experimental and theoretical studies, showed for the first time the key role played by the hydroperoxide functional group in the control of the regioselectivity of the cyclization step. Overall, a novel and sustainable synthetic procedure is reported as a new approach for α-branched tetrahydropyrans.

We report a one-pot two-step deracemization strategy for aryl-ring-containing secondary alcohols using a dual biocatalytic system that combines an unspecific peroxygenase and an alcohol dehydrogenase. In this approach, unspecific peroxygenase from Agrocybe aegerita (AaeUPO) catalyzes the non-stereoselective oxidation of secondary alcohols to their corresponding ketones. The resulting ketones are subsequently subjected to enantioselective reduction using the secondary alcohol dehydrogenase from Thermoanaerobacter pseudoethanolicus (TeSADH), affording optically active alcohols with high conversion and enantiomeric excesses of up to 99%. By selecting appropriate TeSADH mutants, the system enables the independent, highly enantioselective synthesis of either alcohol enantiomer. Notably, the AaeUPO-catalyzed oxidation proceeds without external cofactors and generates water as the sole byproduct. This work establishes a useful biocatalytic platform for the asymmetric synthesis of enantiopure alcohols.

Transesterification reactions are fundamental transformations in organic chemistry, yet performing them in aqueous media is challenging because of the competing hydrolysis reaction. In this study, we describe a mutant of alcohol oxidase from Phanerochaete chrysosporium (PcAOx-VPN) that also exhibits transesterification activity. Moreover, PcAOx-VPN displays no detectable hydrolytic activity, owing to its hydrophobic active site, which effectively excludes water. These characteristics make PcAOx-VPN a promising catalyst for transesterification reactions in aqueous media, a context that is typically compromised by competing hydrolysis.

Halophenols (HPs) cause serious problems for the health of living beings and environment due to their toxigenicity, mutagenicity and carcinogenicity. Enzymes have recently attracted significant attention as an eco-friendly and sustainable approach for the environmental remediation of pollutants. In this study, the recombinant unspecific peroxygenase from Agrocybe aegerita (r Aae UPO, recombinantly expressed in Komagataella pastoris known as Pichia pastoris ) was used to degrade five representative HPs (2-Chlorophenol (2-CP), 3-Chlorophenol (3-CP), 4-Chlorophenol (4-CP), 4-Bromophenol (4-BP), and 3-Iodophenol (3-IP)) in the batch and fed-batch systems. r Aae UPO (5 µM) completely removed up to 10 mM HPs from the fed-batch system in 48 h, while the almost complete removal of 2.5 mM 4-CP and 4-BP in batch systems occurred within 72 h. The enzyme was more effective upon slow, continuous fed with H₂O₂ concentrations (2 mM/h) than supplying stoichiometric H₂O₂ from the beginning. The activity of r Aae UPO towards HPs was: 3-IP > 2-CP > 3-CP > 4-BP > 4-CP. These results were also confirmed by molecular docking results. r Aae UPO-catalyzed primary degradation of HPs occurred via catechol formation followed by polymerization. Toxicity assays using E. coli DH5α demonstrated a significant reduction in toxicity after enzymatic degradation of HPs. This study revealed that r Aae UPO is an efficient biocatalyst capable of effectively degrading HPs, showing great potential for environmental bioremediation applications.

Oxidation of secondary alcohols to their corresponding ketones is a transformation of enduring interest in synthetic chemistry. We report a biocatalytic method employing unspecific peroxygenase from Agrocybe aegerita (AaeUPO) using hydrogen peroxide as the sole oxidant, to convert racemic aryl-ring-containing secondary alcohols into their corresponding ketones. The enzyme efficiently oxidizes both enantiomers without stereopreference, producing the desired ketones with minimal to no side products. This approach offers a promising alternative to conventional oxidation methods.

Biosolar conversion harnesses the complementary advantages of photo(electro)catalysis and redox biocatalysis to synthesize fuels and high-value compounds under sunlight. By routing renewable energy inputs through photo(electro)catalytic interfaces to biocatalysts, nature-inspired biosolar systems achieve highly selective and low-carbon chemical synthesis. This integration transcends the intrinsic limits of purely (in)organic or biological catalysis, advancing the frontier of next-generation sustainable chemical synthesis. Here, we introduce a comprehensive conceptual framework for solar-driven biocatalytic devices by elucidating their core mechanisms and thermodynamic foundations across photocatalytic, photoelectrocatalytic, and photovoltaic-photoelectrocatalytic platforms. We further highlight breakthroughs in the design of photobiocatalytic materials and devices, contextualized within coenzyme/mediator recycling, direct electron transfer, and H₂O₂ generation. Finally, we outline future directions toward practical and sustainable biosolar catalysis.

Aromatic dioxygenases (ADOs) catalyse the oxidative cleavage of CC bonds in aromatic olefins, producing valuable aldehydes or ketones. Due to their coenzyme independence, ADOs are attractive catalysts. However, the limited catalytic performance of natural ADOs restricts their broader practical application. Here, we determined the 2.2 Å crystal structure of an ADO from Coniochaeta pulveracea (CpuADO). Structure-guided mutagenesis targeting residues near the active site identified a mutant F349W, which exhibits enhanced catalytic efficiency (k_cat/K_m) toward sinapyl alcohol by about 1.41-fold compared to the wild-type enzyme. In parallel, AI-based computational screening identified a mutant W338D, which shows improved catalytic efficiency for several aromatic olefins, including 1.3-fold for coniferyl alcohol, 1.7-fold for 4-vinylguaiacol, and approximately 12-fold for isoeugenol. Molecular dynamics (MD) simulations revealed stabilised Fe²⁺–CC distances (approximately 5.5 Å in F349W and 4.7–6.2 Å in W338D) and reduced structural fluctuations, indicating improved substrate positioning. These findings provide a structure-based strategy for engineering ADOs with enhanced catalytic performance toward lignin-related aromatic olefins, allowing for more efficient lignin valorisation.

Chiral-substituted carbonyl compounds can be sustainably obtained via asymmetric alkene reduction catalyzed by ene-reductases from the Old Yellow Enzyme (OYE) family. Yet OYEs are seldom implemented in scale-up reactions due to low turnover numbers (TONs). Herein, we demonstrate multigram 150 g/L scale reactions with the thermostable OYE from Thermus scotoductus (0.2 wt %) for the asymmetric reduction of monoterpenes. Best results were achieved with (S)-carvone (7.5 g), affording a record TON of 123,000, with 90% isolated yield and >99% enantiomeric excess of (2R,5S)-dihydrocarvone, and an environmental E-factor of 11.6.

A photoelectrochemical (PEC) device induces electrochemical reactions on the surfaces of light-absorbing semiconductors to harness sunlight for producing valuable chemicals. The most critical issue in PEC devices is the poor stability of semiconductors in electrochemical environments. The stability can be enhanced by applying a transparent and conductive protection layer, which is usually prepared by an oxide thin film with tens of nanometers, on the semiconductor. Nevertheless, ensuring complete impermeability to an electrolyte remains a significant challenge because even a single pinhole in the thin film can lead to the dissolution of the entire underlying semiconductor layer. In this study, we present a facile and reliable protection method applicable to various semiconductors using a thick (200–500 μm) single crystal of TiO₂. The impermeability is ensured by the exceptionally high thickness, without compromising the device performance. We applied the protection layer on a halide perovskite semiconductor well-known for moisture instability, and inductively coupled plasma mass spectrometry rigorously confirmed that there was no dissolution of elements from the halide perovskite film. The robust protection layer also enabled the safe integration of the halide perovskite PEC device and a biocatalyst without concerns about Pb or halide toxicity. An old yellow enzyme from Thermus scotoductus (TsOYE) coupled with the PEC device enabled the trans-hydrogenation of the C 00000000 00000000 00000000 00000000 11111111 00000000 11111111 00000000 00000000 00000000 C bonds, demonstrating the expanded applicability and economic potential of PEC systems for producing fine chemicals and pharmaceutical intermediates.

Unspecific peroxygenases (UPOs) are highly versatile biocatalysts capable of removing various persistent environmental contaminants and performing sustainable chemical transformations. These oxidoreductases contain heme b as their prosthetic group. As all classical peroxidases, they are activated by the molecules of hydrogen peroxide to incorporate the oxygen atom into numerous organic molecules. Alternatively, they can use ascorbate as a cosubstrate. In sequence databases an ever-increasing number of their DNA and protein sequences occurs. Reconstructed molecular phylogeny of the corresponding peroxidase-peroxygenase superfamily reveals a high diversity of gene distribution for UPOs in the whole kingdom of fungi. A majority of identified UPO sequences stems from numerous species of Dikarya. Although members of this superfamily were recently detected also in early diverging fungal lineages, UPOs from the phyla of Mucoromycota, Glomeromycota and Chytridiomycota remain not sufficiently investigated. Moreover, newly discovered genes coding for UPOs were recently identified also among early diverging eukaryotic lineages of amoebas and green algae in various biotops. With a large palette of potential substrates these oxidoreductases serve as a versatile tool in enzyme catalysed synthetic reactions, but their real physiological substrates need to be recognized in the future. Most important among self-sufficient UPO-catalysed reactions are oxyfunctionalizations of various aliphatic and aromatic molecules. In this critical review an outlook is given for investigation and engineering of novel UPO variants including products of directed evolution. Future research on UPOs shall be mainly focused on basal fungal and emerging non-fungal sources for their promising applications in environmentally friendly technologies.

In this study, we present a significant advancement in the field of enzymatic asymmetric reductive amination (ARA) of ketones, a pivotal reaction for chiral amine synthesis. Through a combination of semirational enzyme design and bioprocess development, we achieve the dual activation and stabilization of amine dehydrogenase (AmDH) to meet industrial demands. The engineered AmDH exhibits remarkable catalytic efficiency (turnover number, TON >1,000,000) and exceptional stability (half-life >7 days at 50 °C), with a broadened substrate scope including various aryl alkyl ketones and fatty ketones. Leveraging biobased oleic acid as an activator and stabilizer, we achieved kilogram-scale synthesis of chiral amines. Furthermore, the integration of AmDH with chemical catalysts in chemoenzymatic cascades has enabled the synthesis of a wide array of pharmaceutically relevant amines from diverse substrates, demonstrating the enzyme’s versatility and potential to transform synthetic chemistry.

Hyaluronic acid (HA), a linear polysaccharide composed of alternating β-1,3-glucuronic acid (GlcA) and β-1,4-N-acetylglucosamine (GlcNAc) disaccharide units, is widely utilized in food, pharmaceutical, and cosmetic industries. Conventional in vitro HA biosynthesis is hindered by the reliance on costly nucleotide sugar precursors (UDP-GlcA and UDP-GlcNAc) and inefficient multienzyme coordination. To address these challenges, this study established a cell-free enzymatic cascade system integrating HA de novo synthesis with nucleotide recycling through eight pathway enzymes. By leveraging nucleotide sugar salvage pathways, UDP-GlcA and UDP-GlcNAc were efficiently synthesized from inexpensive monosaccharides, thereby bypassing energy-intensive de novo routes. Soluble expression of Pasteurella multocida hyaluronan synthase (PmHAS) was achieved by truncating its membrane-associated domains to enable sequential glycosyl transferase activity in aqueous systems. A dual ATP/UTP regeneration strategy was further implemented to sustain nucleotide supply, eliminating costly downstream purification. Under optimized conditions, the system produced 1.28 g/L HA within 24 h, with a molecular weight range of 1.28 × 10⁴to 1.02 × 10⁶Da and a substrate conversion yield of 65.9%. This work not only provides an economical platform for scalable HA synthesis but also establishes a modular enzymatic blueprint for engineering complex biopolymers, demonstrating broad applicability in synthetic glycobiology.