通过从实验室保藏的乳酸菌中筛选出1株对亚硒酸钠耐受性较高的菌株LA4,经分光光度法测定得知在69.28 mg(4 mmol/L)亚硒酸钠浓度下,亚硒酸钠的还原量为32.42 mg(1.87 mmol/L),还原效率为46.79%。并将其亚硒酸钠还原产物通过X射线光电子能谱仪(XPS)和透射电子显微镜(TEM)测试,发现乳酸菌LA4能将亚硒酸钠还原为红色单质硒,观察透射电镜(TEM)图发现,添加亚硒酸钠的发酵液中细胞表面以及培养基中出现大量纳米尺寸的球状颗粒,粒径基本在50~200 nm。

Selenium(Se) is one of the important and essential trace elements in human body,but the range between biological activity and toxicity of Se is extremely narrow,so it's easy to show its toxicity.However,Se(0) nanoparticles have an advantage of high security and strong efficiency.In this experiment,LA4 strain with higher tolerance to sodium selenite was selected from lactic acid bacterias in our laboratory.We found that 46.79% of 4 mmol / L Na 2 SeO 3 was reduced by spectrophotometry.We also found LA4 strain could reduce sodium selenite into red elemental selenium by transmission electron microscope(TEM) and X-ray photoelectron spectrometer(XPS) test.We could see a large number of particles from transmission electron microscope pictures of Na 2 SeO 3,some of the particles sticked to the cell surface,but some of the particles were free in the culture medium,their diameters were mainly in the range from 50nm to 200nm.