耐硒海洋菌株的筛选、鉴定及其产纳米硒的抗菌活性

Screening and Identification of Selenium-tolerant Marine Strain and the Antibacterial Activity of Se Nanoparticles It Synthesized

本研究从海洋菌株中筛选出一株对Na_(2)SeO_(3)具有高还原能力的新型菌株,为纳米硒的生物合成提供新的还原体系。首先,对41株来自北冰洋沉积物的海洋菌株进行筛选,通过初筛、复筛,得到对Na2SeO3还原较强的菌株,并对其进行了种属鉴定。随后利用筛选出的菌株进行纳米硒(Selenium nanoparticles,Se NPs)的生物合成。利用傅里叶红外光谱(Fourier transform infrared spectroscopy,FTIR),扫描电镜(Scanning electron microscope,SEM),X射线衍射(X-ray diffraction,XRD),粒度分析等对该菌株生物合成的Se NPs进行了表征,并对其抗菌活性进行了研究。结果表明,72号菌株对Na_(2)SeO_(3)的耐受能力最强,在300 mmol/L浓度条件下能够正常生长且将Na_(2)SeO_(3)还原为纳米硒。经鉴定该菌株为芽孢杆菌,命名为Bacillus sp.Q72。利用该菌株合成的纳米硒为球形颗粒,平均粒径为169.3 nm,电位为-48.1±0.5 mV,其表面存在着氨基和羟基等官能团。Bacillus sp.Q72菌株生物合成的纳米硒对大肠杆菌表现出更优的抑制活性,当纳米硒浓度为200μg/m L时,对大肠杆菌的抑制率达到92.1%。

In this study,a novel strain with high Na_(2)SeO_(3) reducing ability was screened from marine strains,providing a new reduction system for the biosynthesis of Se nanoparticles(SeNPs).Firstly,41 marine strains from Arctic Ocean sediments were screened,and a strain with high selenium-tolerant was obtained and species identified.Subsequently,the screened marine strain was used for the biosynthesis SeNPs and the SeNPs were characterized using Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM),X-ray diffraction(XRD)and particle size analysis.Furthermore,the antibacterial activities of SeNPs were also determined.The results showed that strain 72 had the strongest tolerance to Na_(2)SeO_(3),which could grow in the presence of 300 mmol/L Na_(2)SeO_(3) and reducing it to brick red SeNPs.Subsequently,strain 72 was identified and named as Bacillus sp.Q72.The SeNPs biosynthesized by this strain were spherical particles with an average size of 169.3 nm and a potential of-48.1±0.5 mV.There were amino and hydroxyl groups on their surface.The SeNPs produced by Bacillus sp.Q72 showed better inhibitory activity against E.coli.When the concentration of SeNPs was 200μg/mL,the inhibitory rate against E.coli reached 92.1%.