Molecular identification and functional characterization of two glycosyltransferases genes from Fallopia multiflora

Construction and Optimization of Engineered Saccharomyces cerevisiae for De Novo Synthesis of Phloretin and Its Derivatives

Phloretin and its derivatives are dihydrochalcone compounds with diverse pharmacological properties and biological activities, offering significant potential for applications in the food and pharmaceutical industries. Due to their structural similarity to flavonoids, their extraction and isolation were highly challenging. Although the biosynthesis of phloretin via three distinct pathways has been reported, a systematic comparison within the same host has yet to be conducted. In this study, we employed rational design and synthetic biology approaches to engineer Saccharomyces cerevisiae for de novo synthesis of phloretin and its derivatives. We constructed and evaluated three biosynthetic pathways for phloretin in S. cerevisiae, demonstrating that effective phloretin synthesis is achievable only via the p-coumaryl-CoA pathway. Additionally, by optimizing enzyme screening, strain engineering, and coordinating heterologous pathways with endogenous metabolism, we achieved the highest reported de novo titer of 287.2 mg/L for phloretin, 184.6 mg/L for phlorizin, 103.1 mg/L for trilobatin, and 164.5 mg/L for nothofagin and the first-time synthesis of 4-methylphloretin and hesperetin dihydrochalcone. This study was committed to addressing the growing demand for dihydrochalcones while laying the foundation for the biosynthesis of more complex derivatives.

Facile and selective separation of anthraquinones by alizarin-modified iron oxide magnetic nanoparticles

Anthraquinones are widely distributed in higher plants and possess broad biological activities. The conventional separation procedures for isolating anthraquinones from the plant crude extracts require multiple extraction, concentration, and column chromatography steps. In this study, we synthesized three alizarin (AZ)-modified Fe₃O₄ nanoparticles (Fe₃O₄@AZ, Fe₃O₄@SiO₂-AZ, and Fe₃O₄@SiO₂-PEI-AZ) by thermal solubilization method. Fe₃O₄@SiO₂-PEI-AZ showed strong magnetic responsiveness, high methanol/water dispersion, good recyclability, and high loading capacity for anthraquinones. To evaluate the feasibility of using Fe₃O₄@SiO₂-PEI-AZ for separating various aromatic compounds, we employed molecular dynamics simulations to predict the adsorption/desorption effects of PEI-AZ for various aromatic compounds in different methanol concentrations. The results showed that the anthraquinones could be efficiently separated from the monocyclic and bicyclic aromatic compounds by adjusting the methanol/water ratio. The Fe₃O₄@SiO₂-PEI-AZ nanoparticles were then used to separate the anthraquinones from the rhubarb extract. At 5% methanol, all the anthraquinones were adsorbed by the nanoparticles, thus allowing their separation from other components in the crude extract. Compared with the conventional separation methods, this adsorption method has the advantages of high adsorption specificity, simple operation, and solvent saving. This method sheds light on the future application of functionalized Fe₃O₄ magnetic nanoparticles to selectively separate desired components from complex plant and microbial crude extracts.