Synthesis of silver nanoparticles by solar irradiation of cell-free Bacillus amyloliquefaciens extracts and AgNO3.
Silver nanoparticles (AgNPs) were obtained by solar irradiation of cell-free extracts of Bacillusamyloliquefaciens and AgNO3. Light intensity, extract concentration, and NaCl addition influenced the synthesis of AgNPs. Under optimized conditions (solar intensity 70,000 lx, extract concentration 3 mg/mL, and NaCl content 2 mM), 98.23±0.06% of the Ag+ (1 mM) was reduced to AgNPs within 80 min, and the ζ-potential of AgNPs reached -70.84±0.66 mV. TEM (Transmission electron microscopy) and XRD (X-ray diffraction) analysis confirmed that circular and triangular crystalline AgNPs with mean diameter of 14.6 nm were synthesized. Since heat-inactivated extracts also mediated the formation of AgNPs, enzymatic reactions are likely not involved in AgNPs formation. A high absolute ζ-potential value of the AgNPs, possibly caused by interaction with proteins likely explains the high stability of AgNPs suspensions. AgNPs showed antimicrobial activity against Bacillussubtilis and Escherichiacoli in liquid and solid medium.
Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
Xuetuan
X
Wei
Mingfang
M
Luo
Wei
W
Li
Liangrong
L
Yang
Xiangfeng
X
Liang
Lin
L
Xu
Peng
P
Kong
Huizhou
H
Liu
D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000494:pharmacology; D001407:Bacillus / Q000378:metabolism* / Q000528:radiation effects*; D001412:Bacillus subtilis / Q000187:drug effects / Q000254:growth & development; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D008826:Microbial Sensitivity Tests; D012834:Silver / Q000378:metabolism*; D012835:Silver Nitrate / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D013056:Spectrophotometry, Ultraviolet; D013472:Sunlight
D000900:Anti-Bacterial Agents; D012834:Silver; D012965:Sodium Chloride; D012835:Silver Nitrate