An Enhancement of Antibacterial Activity and Synergistic Effect of Biosynthesized Silver Nanoparticles by Eurotium cristatum with Various Antibiotics

• Published in: Biotechnology and bioprocess engineering 2020, 25(3), , pp.450-458
• Main Authors: Lin, Pei, Wang, Fu-Qing, Li, Chang-Tian, Yan, Zheng-Fei
• Format: Article
• Language: English
• Subjects: Antibacterial activity; Antibiotics; Biosynthesis; Biotechnology; Chemistry; Chemistry and Materials Science; Diffraction patterns; E coli; Eurotium; Fourier transforms; Functional groups; Image transmission; Industrial and Production Engineering; Infrared radiation; Nanoparticles; Neomycin; Pseudomonas aeruginosa; Research Paper; Silver; Spectrophotometry; Strains (organisms); Synergistic effect; Tea; Transmission electron microscopy; X-ray diffraction; 생물공학
• ISSN: 1226-8372; 1976-3816
• DOI: 10.1007/s12257-019-0506-7

In this study, biosynthesis of silver nanoparticles (AgNPs) by using Eurotium cristatum , isolated from Fuzhuan brick-tea and its antibacterial activity has been demonstrated. AgNPs were characterized at 425 nm as maximum absorbance peak by ultraviolet-visible spectrophotometry. The images of transmission electron microscopy revealed that AgNPs are spherical shape with at 15–20 nm in size. The X-ray diffraction pattern corresponding to planes (111), (200), (220), (311), and (222) demonstrated the crystalline nature of AgNPs. Fourier transform infrared spectrum showed that functional groups involved in reduction of silver ions to metal nanoparticles. For antibacterial application, AgNPs showed antibacterial activity against Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, Candida albicans , and Bacillus subtilis. It also acted synergistically with various antibiotics to inhibit growth of pathogenic strains, which produced an effect greater than the sum of their individual effects. For neomycin with no resistance to C. albicans , it combined with AgNPs, which had significant synergistic effect against C. albicans , with maximum inhibitory zone at 20.9 mm, which was 2.5-fold greater than that of AgNPs alone (8.2 mm). Other antibiotics combined with AgNPs also existed similar synergistic effect. Therefore, AgNPs-synthesized by E. cristatum could enhance antibacterial activity in combination with antibiotics against pathogenic strains through synergistic effects. It might provide a new strategy for treatment of resistant bacteria.