利用副干酪乳酪杆菌SCFF20高效生物合成纳米硒颗粒：一种潜在的亚硒酸盐生物转化工厂

Efficient biosynthesis of selenium nanoparticles by Lacticaseibacillus paracasei SCFF20: a potential cell factory for selenite conversion

摘要:

【目的】硒(Se)是人体必需的微量元素，在维持人体生理代谢中起着至关重要的作用。在硒的各种形态中，纳米硒颗粒(selenium nanoparticles, SeNPs)被发现具有较高的生物利用度和较低的毒性。本研究拟筛选一株能将亚硒酸盐高效合成纳米硒颗粒的益生菌菌株。【方法】从14株潜在益生菌中筛选出一株能有效将亚硒酸钠转化为SeNPs的耐硒菌株副干酪乳酪杆菌SCFF20。利用扫描电子显微镜X射线能量色散谱仪(scanning electron microscopy coupled with energy-dispersive X-ray, SEM-EDX)、动态光散射(dynamic light scattering, DLS)、X射线衍射仪(X-ray diffractometer, XRD)、拉曼光谱(Raman spectroscopy)和傅里叶变换红外光谱(Fourier transform infrared spectroscopy, FTIR)对副干酪乳酪杆菌SCFF20产生的SeNPs进行纯化、冷冻干燥和系统表征。【结果】SEM-EDX分析表明，Se是生物纳米硒颗粒的主要成分。合成的SeNPs呈球形、多分散、平均粒径约为500.62 nm。XRD图谱和拉曼光谱证实所制备纳米硒颗粒的生物无定形性质。FTIR分析证明蛋白质、胞外多糖和脂质包覆在SeNPs表面。电感耦合等离子体发射光谱(inductively coupled plasma-optical emission spectroscopy, ICP-OES)测得SeNPs的还原率为91.42%。【结论】本研究证实了副干酪乳酪杆菌SCFF20作为纳米硒生产益生菌的潜力，可作为安全生产生物源纳米硒的生物工厂以便用于营养补充剂和功能食品

Abstract:

[Objective] Selenium (Se) is an essential trace element playing a critical role in maintaining the physiological metabolism of humans. Among its various forms, selenium nanoparticles (SeNPs) possess higher bioavailability and lower toxicity. The study aims to screen a probiotic strain that can efficiently synthesize SeNPs from selenite. [Methods] Lacticaseibacillus paracasei SCFF20 capable of converting sodium selenite to SeNPs was screened out from 14 strains of probiotics. The SeNPs produced by L. paracasei SCFF20 were purified, freeze-dried, and systematically characterized by scanning electron microscopy coupled with energy-dispersive X-ray (SEM-EDX), dynamic light scattering (DLS), X-ray diffractometer (XRD), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). [Results] SEM-EDX results revealed that Se was the primary constituent of SeNPs. The synthesized SeNPs were spherical and polydisperse, with an average particle size of 500.62 nm. XRD and Raman spectroscopy confirmed that the SeNPs were amorphous. Additionally, FTIR demonstrated the presence of proteins, exopolysaccharides, and lipids coating the surface of the SeNPs. Moreover, the reduction rate of SeNPs was determined to be 91.42% by inductively coupled plasma-optical emission spectroscopy (ICP-OES). [Conclusion] The findings of this study highlight the potential of L. paracasei SCFF20 as a probiotic strain capable of producing SeNPs. The strain can be used as a cell factory for the safe production of biogenic SeNPs as nutritional supplements and functional food.