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从石斛中分离得到一株内生真菌DO-1,该菌株经鉴定为禾谷镰刀菌(Fusarium graminearum),其菌体在去离子水中浸泡后分泌的代谢产物与硝酸银作用后,能还原银离子产生具有抗菌作用的纳米银粒子。以440~450 nm范围内纳米银的特征性等离子吸收峰以及产物抑菌活性为指标,研究光照条件、温度以及p H条件对制备纳米银粒子的影响。黑暗条件和适当高温有助于纳米银粒子的生成及其抑菌活性的增强。随着p H的增加,纳米银特征性吸收峰不断增强,但抑菌活性呈现先增强再减弱的趋势,p H 7~8范围内得到的纳米银粒子的抑菌活性较高。调节F.graminearum DO-1菌体浸泡液的p H为7,与终浓度为1 m M的Ag NO3溶液于80℃、黑暗条件下反应3 h,获得纳米银粒子,透射电镜分析显示制备的纳米银粒子为球形,直径范围2~50 nm。应用该内生真菌代谢产物制备具有抑菌功能的纳米银粒子,方法简单,条件温和,复合绿色生态的发展趋势。
An endophytic fungus DO-1 was isolated from Dendrobium. The strain was identified as Fusarium graminearum, and the metabolites secreted by soaking in deionized water reacted with silver nitrate to reduce silver Ions produce antimicrobial silver nanoparticles. The characteristic plasma absorption peaks of nanosilver in the range of 440-450 nm and the antibacterial activity of the nanosilver were taken as indexes to study the influence of light conditions, temperature and p H conditions on the preparation of nanosilver particles. Dark conditions and appropriate high temperature contribute to the formation of nano-silver particles and enhanced antibacterial activity. With the increase of p H, the characteristic absorption peak of nanosilver increased continuously, but the antibacterial activity tended to increase firstly and then decreased. The antibacterial activity of the nanosilver particles in the range of p H 7 ~ 8 was higher. The p H of F.graminearum DO-1 soaking solution was adjusted to 7, and Ag NO3 solution with a final concentration of 1 m M was reacted at 80 ℃ for 3 h under dark conditions to obtain silver nanoparticles. Transmission electron microscopy analysis showed that the prepared Silver nanoparticles are spherical and have diameters in the range of 2 to 50 nm. The endophytic fungi metabolites are used to prepare nano silver particles with antibacterial function, and the method has the advantages of simple method, mild condition and complex green ecological trend.