关键词: 银纳米颗粒, 生物还原, 非酶催化, 黑曲霉菌, 抗菌性能

Abstract: A facile and eco-friendly route was presented to in-situ synthesize and immobilize silver nanoparticles (AgNPs, 6.9—8.2 nm)using Aspergillus nigeras both reducing agent and support through the non-enzymatic reduction mechanism.The well-dispersed AgNPs/mycelium composite exhibited excellent antimicrobial activity against E.coli, and the minimal inhibitory concentration (MIC)was 217—434 mg·L^-1(based on the mass of AgNPs/mycelium)or 8—20 mg·L^-1(based on the mass of AgNPs).Although increasing reaction temperature from 30℃ to 60℃ resulted in increase of silver loading, the mean size of the AgNPs became larger at the same time, leading to the decrease of antimicrobial activity.The change of pH value from 9.5 to 11.5 promoted the reaction rate and shortened the reaction time (from 144 h to 24 h), whereas no significant effect was observed on the antimicrobial activity. Finally,the release of AgNPs and Ag⁺ from the AgNPs/mycelium composite was investigated. The results suggested that the prepared AgNPs were supported firmly on Aspergillus niger and the release of Ag⁺ was 1.7—6.8 mg per gram of AgNPs/mycelium.Furthermore, increasing reaction temperature or pH value led to the decrease of Ag⁺ release.

Key words: silver nanoparticles, bioreduction, non-enzymatic, Aspergillus niger, antibacterial performance