硒(Se)由于其优异的反应性和优异的生物利用度,作为健康补充剂的需求量很大,尽管硒纳米颗粒(SeNPs)有轻微毒性的迹象。目前,使用乳酸菌制备SeNPs的效率不令人满意。因此,需要一种高效地将亚硒酸盐转化为元素硒的益生菌菌株。在我们的工作中,从土壤样品中分离出四种亚硒酸盐还原细菌。被鉴定为乳酸片球菌DSM20284的LAB-Se2菌株在环境温度下具有高达98%的减少率。该菌株可以在pH4.5-6.0,温度30-40°C的48小时内将100mgL-1的亚硒酸盐还原为元素Se,盐度为1.0-6.5%。纯化产生的SeNPs,冻干,随后使用FTIR系统表征,DSL,SEM-EDS,和TEM技术。SEM-EDS分析证明硒是SeNPs的最主要成分。菌株能够形成球形SeNPs,通过TEM测定。此外,DLS分析证实,SeNP带负电荷(-26.9mV),平均粒度为239.6nm。SeNP的FTIR分析表明蛋白质和多糖作为SeNP上的加帽剂。酸乳杆菌合成的SeNPs对大肠杆菌具有显著的抗菌活性,B.枯草杆菌,金黄色葡萄球菌,和肺炎克雷伯菌,抑制区为17.5毫米,13.4mm,27.9mm,和16.2毫米,分别;他们还显示出在15-120μgmL-1范围内的不同MIC值。DPPH,ABTS,和羟基,SeNPs的超氧化物清除活性为70.3%,72.8%,95.2%,和85.7%,分别。由益生菌乳酸乳球菌合成的SeNPs具有在生物医学和营养应用中安全使用的潜力。
Selenium (Se) is in great demand as a health supplement due to its superior reactivity and excellent bioavailability, despite selenium nanoparticles (SeNPs) having signs of minor toxicity. At present, the efficiency of preparing SeNPs using lactic acid bacteria is unsatisfactory. Therefore, a probiotic bacterial strain that is highly efficient at converting selenite to elemental selenium is needed. In our work, four selenite-reducing bacteria were isolated from soil samples. Strain LAB-Se2, identified as Pediococcus acidilactici DSM20284, had a reduction rate of up to 98% at ambient temperature. This strain could reduce 100 mg L-1 of selenite to elemental Se within 48 h at pH 4.5-6.0, a temperature of 30-40 °C, and a salinity of 1.0-6.5%. The produced SeNPs were purified, freeze-dried, and subsequently systematically characterised using FTIR, DSL, SEM-EDS, and TEM techniques. SEM-EDS analysis proved the presence of selenium as the foremost constituent of SeNPs. The strain was able to form spherical SeNPs, as determined by TEM. In addition, DLS analysis confirmed that SeNPs were negatively charged (-26.9 mV) with an average particle size of 239.6 nm. FTIR analysis of the SeNPs indicated proteins and polysaccharides as capping agents on the SeNPs. The SeNPs synthesised by P. acidilactici showed remarkable antibacterial activity against E. coli, B. subtilis, S. aureus, and K. pneumoniae with inhibition zones of 17.5 mm, 13.4 mm, 27.9 mm, and 16.2 mm, respectively; they also showed varied MIC values in the range of 15-120 μg mL-1. The DPPH, ABTS, and hydroxyl, and superoxide scavenging activities of the SeNPs were 70.3%, 72.8%, 95.2%, and 85.7%, respectively. The SeNPs synthesised by the probiotic Lactococcus lactis have the potential for safe use in biomedical and nutritional applications.