The discovery of epoxide hydrolases within a Streptomyces sp. strain collection is described. Screening was performed in 96 well microtiter plates using a modified 4-(p-nitrobenzyl)pyridine assay with styrene oxide, 1,2-epoxy-hexane or 3-phenyl ethylglycidate (3-PEG) as substrates. Out of 120 strains investigated, S. antibioticus Tü4, S. arenae Tü495 and S. fradiae Tü27 exhibited epoxide hydrolase activity. These strains were further investigated by performing laboratory-scale biotransformations utilizing styrene oxide, 1,2-epoxy-hexane and 3-PEG followed by subsequent quantitative analysis employing chiral gas chromatography. The highest conversions were achieved with whole cells from S. antibioticus Tü4 in the presence of 10% (v/v) DMSO. However, enantioselectivity was only satisfying (E = 31) in the presence of 5% (v/v) acetone, which allowed isolation of optically pure non-hydrolyzed (R)-styrene oxide (99% enantiomeric excess (ee)) and (S)-phenyl-1,2-ethandiol (72% ee) at 55% conversion after 24 h. The resolution of 3-PEG proceeded with slightly lower enantioselectivity albeit higher reaction rates. With S. fradiae Tü27 and S. arenae Tü495 enantioselectivity towards styrene oxide was only E = 3-4.
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http://dx.doi.org/10.1016/s0168-1656(99)00225-4 | DOI Listing |
Enzyme Microb Technol
January 2025
Dabie Mountain Laboratory, College of Tea and Food Science, Xinyang Normal University, Xinyang, Henan 464000, China.
2-Phenylethanol, an aromatic alcohol with a rose scent, is widely used in the cosmetics, food, and pharmaceutical industries. We designed an efficient multi-enzyme cascade pathway for production of 2-phenylethanol from styrene as the substrate. Initially, 2-phenylethanol was produced by overexpression of styrene monooxygenase A (styA), styrene monooxygenase B (styB), styrene oxide isomerase (SOI), alcohol dehydrogenase (yahK), and glucose dehydrogenase (gdh) in Escherichia coli to give 6.
View Article and Find Full Text PDFInorg Chem
January 2025
Henan Key Laboratory of Polyoxometalate Chemistry, College of Chemistry and Molecular Sciences, Henan University, Kaifeng, Henan 475004, China.
Revealing the design and synthesis of precisely tailored crystalline catalysts for achieving efficient photocatalytic conversion of styrene into high-value-added products remains a challenging task. In this work, a highly stable crystalline polyoxovanadate functionalized by the dl-tartaric acid ligand H[VO(HO)(tart)]·HO [, tart = CHO] was successfully synthesized by conventional aqueous solution methods. The photocatalytic performance was evaluated for the photosynthesis of styrene oxide by employing an oxygen source as the oxidant in the visible light (>420 nm) conditions at room temperature with compound as a heterogeneous catalyst.
View Article and Find Full Text PDFOrg Biomol Chem
January 2025
State Key Laboratory Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30 Puzhu Road South, Nanjing 211816, China.
The cycloaddition of CO to epoxide (CCE) reactions produce valuable cyclic carbonates useful in the electrolytes of lithium-ion batteries, as organic solvents, and in polymeric materials. However, halide-containing catalysts are predominantly used in these reactions, despite halides being notoriously corrosive to steel processing equipment and residual halides also having harmful effects. To eliminate the reliance on halides as cocatalyst in most CCE reactions, halide-free catalysts are highly desirable.
View Article and Find Full Text PDFChemistry
December 2024
Lanzhou University, College of Chemistry and Chemical Engineering, Lanzhou Tianshui south street 222, 730000, Lanzhou, CHINA.
Dual single-atom catalysts have attracted considerable research interest due to their higher metal atom loading and more flexible active sites compared to single-atom catalysts (SACs). We pioneered the one-step synthesis of sheets copper-cobalt graphitic carbon nitride dual single-atom (S-Cu/Co-g-C3N4) using folding fan-shaped aluminum foil as a template, and used them as catalysts in the epoxidation of styrene respectively. Through XAFS(X-ray Absorption Fine Structure) and other characterizations, it is found that Cu and Co single atoms are stabilized separately on g-C3N4 via coordination with nitrogen (N), hindered the ordered growth of sheets, and formed more pore structures, which not only increased more catalytically active sites, but also effectively prevented the flakes re-aggregate during the catalytic process.
View Article and Find Full Text PDFACS Nanosci Au
December 2024
Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8551, Japan.
The dynamic control of chiral (enantiomeric) responses in chiral host-guest complexes through external stimuli is a significant challenge in modern chemistry for developing smart stimuli-responsive materials. Herein, we report the (chir)optical properties and chiral recognition behavior of water-soluble chiral naphthotubes () under the influence of hydrostatic pressure as an external stimulus. The hydrostatic pressure spectral profiles compared to those obtained at normal pressure revealed the dynamic behavior of under hydrostatic pressure, owing to the flexible linker.
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