In response to the widespread environmental concern of endocrine disruptors, our research investigated the aerobic biodegradation of dexamethasone (DEX), a widely used synthetic glucocorticoid with endocrine-disrupting properties, by strain Rhodococcus sp. D32. This innovative strain showcases remarkable DEX-degrading capabilities, with the half-life for degrading 500 μg/L DEX in MH broth being just 7.56 h. Utilizing high-resolution mass spectrometry, we identified six transformation products (TPs) and revealed a unique steroid nucleus-opening pathway marked by A-ring lactonization and subsequent lactone hydrolysis. This newly discovered pathway deviates from the classical steroid 9,10-seco pathways and previous transformations that preserved the intact steroid nucleus, thus expanding our knowledge of microbial steroid transformations. Additionally, the degradation process progressively converts the parent DEX into less ecotoxic products, significantly reducing the overall ecotoxicity of the system. This reduction remains evident when considering the combined toxicity of DEX and its TPs, indicating a promising approach for lessening environmental harm. Strain D32 also proved effective in various authentic aquatic environments, including fishpond water, urban sewage, river water, and reservoir water, where its introduction markedly expedited the dissipation of DEX. Our findings underscore the potential of strain D32 as a powerful tool for the bioremediation of DEX, presenting an efficient and eco-friendly strategy to alleviate the effects of this endocrine disruptor in aquatic ecosystems.
Zhong-Xia Wang,Hua Zhang,Fang Wang,Hao Cheng,Wen-Hui He,Yu-Hua Liu,Xue-Qin Huang,Peng-Fei Li
Piezoelectric materials with inherent mechanical–electric coupling effect are a crucial family of functional materials in high-end information technology. For practical applications, the transverse piezoelectric performance (d31 or d32) is mainly considered, because this parameter is a vitally important index to characterize the performance of piezoelectric thin films. However, the transverse piezoelectricity of the thin films as a key figure of merit is seldom mentioned in molecular ferroelectrics. Herein, we report that a new 1D halide perovskite ferroelectric N,N-dimethylallylammoniumCdCl3 (DMAACdCl3) exhibits an above room-temperature ferroelectric phase transition with a saturated polarization of 1.9 μC cm–2 and a coercive field of 5.0 kV cm–1. The thin film of DMAACdCl3 is successfully fabricated using an easy processing spinning method and maintains well ferroelectric properties verified by piezoresponse force microscopy (PFM). More significantly, the ferroelectric thin film offers superior transverse piezoelectricity with an in-plane piezoelectric response of about 41 pC N–1, which is about twice that of well-known piezoelectric polymer PVDF (21 pC N–1). Transverse piezoelectricity has been scarcely studied in molecular ferroelectrics, and its exploitation would play an important role in the design of next-generation smart piezoelectric devices.
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