Hubei University of Technology

Astaxanthin biosynthesis in engineered bacteria commonly relies on CrtW/CrtZ enzymes, whereas functional reconstruction of the yeast P450-type CrtS/CrtR module in Escherichia coli remains less established. Here, crtS and crtR from Xanthophyllomyces dendrorhous were introduced into pBR322-derived vectors and co-expressed with pAC-BETAipi in E. coli DH5α. The parental pAC-BETAipi strain and the CrtS/CrtR co-expression strain showed comparable growth profiles. HPLC analysis of the co-expression strain revealed an astaxanthin-associated target peak at 2.734 min. After addition of the astaxanthin standard to the same extract, the target-peak area increased from 448,930 to 812,037 while the retention time remained essentially unchanged (2.734 versus 2.732 min). Among five carbon sources, maltose gave the highest wet-biomass-normalized target-peak yield (16.28 ± 0.29 μg/g; P < 0.05). Under a nominal C/N ratio of 6:1, product selectivity reached 73.8%. These results support functional compatibility of the yeast CrtS/CrtR module with a bacterial β-carotene background and identify culture conditions favoring the astaxanthin-associated target peak.

Quercetin (QCT), a flavonoid polyphenol, is the main active component responsible for the antioxidant and anti-inflammatory effects of various medicinal herbs. However, excessive intake of QCT is prone to cause adverse reactions such as vomiting and hypokalemia, so it is of great significance to establish a portable and highly sensitive method for QCT detection. Integrating fluorescence, colorimetry, and smartphone-based portable sensing into a single material matrix can achieve high-sensitivity and rapid visual multimodal synergistic detection, and significantly improve the detection accuracy and anti-interference ability through signal complementarity and mutual verification. Therefore, a single-emission blue fluorescence sensor (UNDC) based on Zr-based metal-organic framework (Zr-MOF) was prepared in this work, which exhibited a highly sensitive fluorescence quenching response to QCT with a detection limit as low as 0.59 nM. Furthermore, a dual-emission red fluorescence sensor (EuUNDC) was developed by introducing the red luminescent center Eu³⁺ into UNDC. EuUNDC not only maintained a sensitive fluorescence quenching response to QCT but also possessed excellent selectivity and anti-interference ability; meanwhile, it could realize colorimetric quantitative detection of QCT through UV-vis absorption spectroscopy and was successfully applied to the quantitative analysis of QCT in licorice tablets. Additionally, the portable paper sensor prepared based on EuUNDC could achieve on-site visual quantitative detection of QCT. Thus, the dual-mode fluorescent/colorimetric sensing platform constructed in this work and the smartphone-based portable sensor achieve high-sensitivity, high-selectivity, and on-site visual quantitative detection of QCT, and has broad application prospects in the field of pharmaceutical active substance analysis.

The rapid development of human-interactive wearable devices has created urgent demands for energy storage materials that simultaneously achieve reliable electrochemical performance, skin conformability, and operational safety. However, conventional hydrogel electrolytes face persistent challenges in balancing mechanical robustness with ionic transport efficiency. In this study, a covalent-ionic hybrid protein network electrolyte was developed by exploiting the covalent cross-linking provided by the thiol-ene click reaction, and lithium-ion (Li⁺) -mediated ionic coordination. The synergistic covalent crosslinking and dynamic ionic interactions simultaneously enhance mechanical stability and ion-transport capability, thereby establishing continuous ion-migration pathways throughout the three-dimensional network. The Li⁺-protein based electrolyte (1.5 M Li⁺) delivers a specific capacitance of ∼194 mF/cm², substantially higher than that of the Li⁺-free counterpart (∼115 mF cm^-2), demonstrating the critical role of Li⁺ regulation in enhancing electrochemical performance. The assembled flexible supercapacitor exhibits excellent electrochemical reversibility, maintaining nearly unchanged cyclic voltammetry (CV) profiles and galvanostatic charge discharge (GCD) curves during continuous operation. Moreover, the device preserves stable electrochemical characteristics under bending deformations of 45° and 90°, achieving a specific capacitance of ∼265 mF cm^-2 even under 90° bending. The favorable biosafety and skin-compatible characteristics of the protein-based electrolyte further highlight its potential for wearable and human-interactive energy storage systems.