Production of the antifungal biopesticide physcion through the combination of microbial fermentation and chemical post-treatment

Abstract Physcion is an anthraquinone compound observed dominantly in medicinal herbs. This anthraquinone possesses a variety of pharmaceutically important activities and has been developed to be a widely used antifungal biopesticide. Herein, we report on the effective preparation of 3R-torosachrysone (4), a tetrahydroanthracene precursor of physcion, in Aspergillus oryzae NSAR1 by heterologous expression of related genes mined from the phlegmacins-producing ascomycete Talaromyces sp. F08Z-0631. Conditions for converting 4 into physcion were studied and optimized, leading to the development of a concise approach for extracting high-purity physcion from the alkali-treated fermentation broth of the 4-producing A. oryzae strain. Graphical Abstrac

Comparative Study on Properties, Structural Changes, and Isomerization of Cis/Trans-Stilbene under High Pressure

The comparison of different stereoisomeric organic compounds under high pressure has been less investigated. Here, we chose different stereochemical configurations of cis/trans-stilbene to study the luminescence properties, polymerization reaction, and structural changes at 0–20 GPa by spectroscopy and XRD. No fluorescence enhancement occurred in cis-stilbene due to π–π stacking. At 16 GPa, the IR, UV–vis, and sample color changes show that it undergoes an irreversible polymerization, that C(sp2)–H changes to C(sp2 + sp3)–H. However, trans-stilbene undergoes fluorescence enhancement at 0–4 GPa due to the reduction of the torsion angle of the benzene ring and the CC bond leading to the formation of rigid planar molecules, which is further confirmed by the IR and XRD results. At 8 GPa, the new peaks in UV–vis and XRD results show the formation of new substances by structural change. However, the structure of trans-stilbene is more stable, which leads to the return to the raw state after releasing the pressure, and a reversible transformation occurs at high pressure. The cis-trans isomerization under high pressure was also briefly investigated by combining heating and laser irradiation. The cis → trans-stilbene transition can only happen under a fixed-range light irradiation, and the trans → cis-stilbene transition could not happen even under irradiation with a 360 nm laser, which may provide a new idea for synthesizing trans isomers with a higher purity

Anomalous polarization enhancement in a van der Waals ferroelectric material under pressure

Abstract CuInP2S6 with robust room-temperature ferroelectricity has recently attracted much attention due to the spatial instability of its Cu cations and the van der Waals (vdW) layered structure. Herein, we report a significant enhancement of its remanent polarization by more than 50% from 4.06 to 6.36 µC cm−2 under a small pressure between 0.26 to 1.40 GPa. Comprehensive analysis suggests that even though the hydrostatic pressure suppresses the crystal distortion, it initially forces Cu cations to largely occupy the interlayer sites, causing the spontaneous polarization to increase. Under intermediate pressure, the condensation of Cu cations to the ground state and the polarization increase due cell volume reduction compensate each other, resulting in a constant polarization. Under high pressure, the migration of Cu cations to the center of the S octahedron dominates the polarization decrease. These findings improve our understanding of this fascinating vdW ferroelectric material, and suggest new ways to improve its properties

Tuning of Interlayer Interaction in MoS₂–WS₂ van der Waals Heterostructures Using Hydrostatic Pressure

Van der Waals heterostructures have recently attracted great interest of the scientific community due to their rich exotic physical properties and extensive application prospects. Therefore, we conducted pressure-dependent Raman and photoluminescence spectroscopic studies on MoS2–WS2 heterostructures in different twist angles (24.5 and 54°). Thus, it was confirmed that as the interlayer interaction increases under pressure, an electronic phase transition and a structural phase transition due to layer sliding are observed at ∼1.8 and ∼3.8 GPa in the HS-24.5° structures, while no phase transition is observed in the HS-54° structures. As a result of a larger tunable interlayer space in HS-24.5° structures, optical properties of HS-24.5° structures are more pressure-sensitive than those of the HS-54° structure. It is expected that this work will help comprehensively establish the correlation between the interlayer interactions and optical properties of vdW HSs at the atomic level. Understanding this correlation is crucial for the development of new excitonic devices