嗜酸乳杆菌(Lactobacillus acidophilus)合成纳米硒特性研究

Transformation of Selenium Nanoparticles by Lactobacillus acidophilus and Biological Activities of Selenium Nanoparticles Produced

乳酸菌具有还原亚硒酸钠为纳米硒的能力。为了采用更加环境友好的方式获得纳米硒颗粒,本研究首先探索了培养基中加硒浓度、加硒时间,以及培养时长对嗜酸乳杆菌(Lactobacillus acidophilus)合成纳米硒的影响,随后对所产的纳米硒颗粒的粒径、zeta电位及抑菌活性进行研究。结果表明,当培养基中硒含量为0~600μg/mL时,硒浓度越高,转化得到的纳米硒越多;当培养基中硒浓度高于600μg/mL时,发酵液中的纳米硒含量反而减少。在嗜酸乳杆菌生长的对数中前期,即第6 h时添加亚硒酸钠,更有利于纳米硒的合成。而培养至32 h后,纳米硒几乎不再继续合成。通过扫描电镜及粒径和电位仪分析发现,嗜酸乳杆菌所产的纳米硒颗粒呈球形,且超声破碎有助于其释放;纳米硒颗粒带负电荷,电位绝对值为40~50 mV,粒径大小较多分布于170~210 nm,具有良好的稳定性。抑菌实验结果表明,嗜酸乳杆菌还原亚硒酸钠所产的纳米硒对大肠杆菌、沙门氏菌、金黄色葡萄球菌和枯草芽孢杆菌的生长均具有抑制作用。综上,嗜酸乳杆菌可以将亚硒酸钠还原合成纳米硒,且所产的纳米硒颗粒具有良好的抑菌活性。

Lactic acid bacteria have the ability to reduce sodium selenite to selenium nanoparticles(SeNPs).To obtain SeNPs in a more environmentally friendly way,this study first explored the effects of selenium concentration in the medium,selenium addition time and cultivating duration on the synthesis of SeNPs by Lactobacillus acidophilus,followed by a study of the particle size,zeta potential and antibacterial activity of the SeNPs produced.The results showed that when the selenium content in the medium was 0~600μg/mL,the higher the selenium concentration was,the more nano-selenium was obtained.When the selenium concentration in the medium was higher than 600μg/mL,the content of SeNPs in the fermentation broth decreased.The addition of sodium selenite in the early logarithmic stage of bacterial growth was more conducive to the synthesis of SeNPs.After 32 h of culture,SeNPs were almost no longer synthesized.The analysis using scanning electron microscopy and particle size and zeta potential analyzer revealed that the SeNPs produced by L.acidophilus were spherical in shape.Ultrasound treatment contributed to their release.The SeNPs carried a negative charge,with an absolute potential value of 40~50 mV,and their particle size predominantly ranged from 170~210 nm,exhibiting good stability.The results of antibacterial experiments showed that the SeNPs produced by L.acidophilus had inhibitory effects on the growth of Escherichia coli,Salmonella,Staphylococcus aureus and Bacillus subtilis.In conclusion,L.acidophilus can transform sodium selenite into SeNPs,which have good antibacterial activity.