多粘类芽孢杆菌绿色制备纳米银及其抑菌活性

Green Preparation of Silver Nanoparticles by Paenibacillus polymyxa 381 and its Antibacterial Activity

摘要: 本文利用一株桑叶内生菌——多粘类芽孢杆菌381的无细胞发酵液进行纳米银的胞外合成。微生物合成的纳米银溶液呈现红棕色，紫外全波长扫描结果显示在418 nm处有典型吸收峰。对纳米银合成的条件进行优选，结果表明，以内生菌株的LB培养液为还原剂和稳定剂，在与0.01 M硝酸银溶液以1:1体积比条件下37℃避光反应72 h，可以获得分散性良好的纳米银颗粒溶液。偏碱性条件有利于菌株发酵液还原制备纳米银，以pH 9时效果最好。平板打孔法实验表明，纳米银溶液随剂量增加，对桑青枯菌和金黄色葡萄球菌的抑制作用均可增强，但对桑疫病菌的抑制效果不明显。液体培养法表明，合成的纳米银溶液对两株病原菌的最小抑菌浓度分别为50和30 ug/mL。

Abstract: In this paper, the extracellular synthesis of silver nanoparticles was carried out in a cell-free fermentation broth of an endophyte of mulberry leaves, Paenibacillus polymyxa 381. The silver nanoparticles solution synthesized by microorganism showed a reddish brown color, and the ultraviolet full-wavelength scanning results showed a typical absorption peak at 418 nm. The conditions for the synthesis of silver nanoparticles were optimized, and the results showed that using the LB culture broth of the inoculant strain as reduced agent and stabilizer, the silver nanoparticles with good dispersion could be obtained by reacting with silver nitrate solution at a 1:1 volume ratio at 37˚C for 72 h. The alkaline condition was favorable for the preparation of silver nanoparticles with the fermentation broth, with the best effect at pH9. The experimental results showed that the inhibition effect of nano silver solution on Ralstonia solanacearum and Staphylococcus aureus could be enhanced with the increase of the dose, but the inhibition effect on Pseudomonas syringae pv. mori was not obvious. The liquid culture method showed that the minimum inhibitory concentration of the synthesized silver nanoparticles to the two pathogens was 50 and 30 ug/mL respectively.