钩状木霉生物合成纳米银及其杀菌性能

Biosynthesis of silver nanoparticles using Trichoderma hamatum and antibacterial activity

【目的】以钩状木霉为微生物材料合成纳米银粒子,并对其杀菌性能进行测定。【方法】将钩状木霉与2 mmol/L的Ag NO3溶液混合暗培养合成纳米银,采用UV-vis、XRD和TEM等方法对纳米银进行表征;利用原子吸收光谱仪和热重分析仪测定并计算银离子的转化率和纳米银的产率;以大肠杆菌和枯草芽孢杆菌为受试菌株检测纳米银的杀菌性能。【结果】钩状木霉与硝酸银混合的培养液颜色为红褐色,UV-vis图谱显示在420 nm左右出现了强的吸收峰;XRD图谱出现了4个特征性衍射峰,分别对应纳米银的4个晶面;TEM照片可以看出纳米银多数为球形,具有单分散性;粒度分布仪显示纳米银具有很窄的粒径分布,在1-13 nm之间,平均粒径为6.69 nm;根据原子光谱吸收仪测定的结果得到银的转化率为84.41%,根据热重分析结果得到纳米银的产率为67.12%;纳米银对大肠杆菌的MBC为10 mg/L,MIC为7 mg/L;对枯草芽孢杆菌的MBC为5 mg/L,MIC为4 mg/L。【结论】钩状木霉与Ag NO3溶液混合培养可以合成纳米银。合成的纳米银大小均匀,粒径小且分布很窄,具有面心立方结构,是纯净的,产率约为67.12%;纳米银对枯草芽孢杆菌的致死效果好于对大肠杆菌的致死效果。

[Objective] To biosynthesis silver nanoparticles using Trichoderma hamatum and detect antibacterial activity of silver nanoparticles. [Methods] Silver nanoparticles were biosynthesized using Trichoderma hamatum mixed with Ag NO3 and were characterized by UV-vis, XRD and TEM. Thermogravimetric analysis and atomic absorption were used to detected productivity of silver nanoparticle and conversion rate of Ag＋. Antibacterial activity of silver nanoparticles was detected using Escherichia coli and Bacillus subtilis. [Results] Culture solution of Trichoderma hamatum mixed with Ag NO3 was reddish-brown; UV-vis spectrum showed a significant peak at 420 nm; XRD spectrum showed four peaks, which corresponded to four crystal faces of silver nanoparticles; TEM images suggested that silver nanoparticles were monodisperse with shape in spherical. Size distribution suggested that they had narrow distribution, between 1–13 nm and the average size was 6.69 nm. Atomic absorption showed conversion rate of Ag＋ was 84.41%. Thermogravimetric analysis showed that the productivity of silver nanoparticles was 67.12%. MBC of silver nanoparticle for E. coli was 10 mg/L and MIC was 7 mg/L, while for Bacillus subtilis was 5 mg/L and 4 mg/L. [Conclusion] After mixed with Ag NO3, Trichoderma hamatum can biosynthesis silver nanoparticles. Silver nanoparticles were uniform, cubic and pure. Lethal effect of silver nanoparticles for Bacillus subtilis was much greater than that for E. coli.