Chunyan Li,Yueling Sun,Guanjun Sun,Hailian Zang,Shanshan Sun,Xinyue Zhao,Ning Hou,Dapeng Li
Triclocarban (TCC) is an emerging and intractable environmental contaminant due to its hydrophobicity and chemical stability. However, the antibacterial property of TCC limits its biodegradation, and only the functional enzyme TccA involved in TCC degradation has been characterized to date. In this study, we report a highly efficient TCC-degrading bacterium, Rhodococcus rhodochrous BX2, that could degrade and mineralize TCC (10 mg/L) by 76.8% and 56.5%, respectively, within 5 days. Subsequently, the TCC biodegradation pathway was predicted based on the detection of metabolites using modern mass spectrometry techniques. Furthermore, an amidase (TccS) and a novel phenol hydroxylase (PH IND ) encoded by the tccS and PH IND genes, respectively, were identified by genomic and transcriptomic analyses of strain BX2, and these enzymes were further unequivocally proven to be the key enzymes responsible for the metabolism of TCC and its intermediate 4-chloroaniline (4-CA) by using a combination of heterologous expression and gene knockout. Our results shed new light on the mechanism of TCC biodegradation and better utilization of microbes to remediate TCC contamination.
Yu Yang,Miao Jiang,Zhuang Ma,Alexandr A. Rogachev,Weizhi Tian,Xin Gao,Baowen Xu,Lihong Gao
Carbon fiber epoxy resin (CFRP) is gradually used as the space satellite antenna material, thermal control coatings (TCCs) are prepared on the surface to ensure the stable operation. However, the traditional TCCs have no wave transmission capability. The hollow glass microspheres (HGMs) were used to prepare the coating in our work, and ZrO 2 was coated on its surface (Zr-HGM) to improve the solar reflectivity. The Zr-HGM powders were obtained by a homogeneous precipitation method with an appropriate reaction time of 4 h. By investigating the optical and dielectric properties, we found that the solar absorption of the coating with Zr-HGM was reduced by half compared to the coating with the original HGM. The microwave transmittances were all above 96.5% from 2 to 18 GHz. Our findings have proposed a preparation method for a new CFRP-based TCC, which will ensure the stable operation of the satellite antenna.
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