Biosynthesis and Characterization of Enterocin Encapsulated Silver Nanoparticles with Improved Antimicrobial, Antibiofilm, and Antioxidant Properties
摘要
The significant increase in antibiotic-resistant strains has emerged as a global concern, necessitating the increased need for the development of novel strategies to overcome this problem. Traditionally, silver has been known for its potent antimicrobial activity, and also, it has been used to enhance the activity of antimicrobial peptides. The present study focuses on the biosynthesis of an antimicrobial peptide enterocin-encapsulated silver nanoparticles, and their enhanced activities. The study initiates with the production of enterocin, by an isolate of Enterococcus faecalis MSW5. The maximum binding efficiency of enterocin-SNPs was observed at ratio of 1:9 enterocin:AgNO3, followed by incubation time of 48 h at pH 10. Further, the characterization of the encapsulated silver nanoparticles was done by UV–Vis spectroscopy, Fourier-transform infrared spectroscopy, transmission electron microscopy, and X-ray diffraction. The results of these characterizations indicated that the enterocin-encapsulated SNPs have a face center cubic crystalline structure with size from 17.5 to 24.7 nm in diameter. The encapsulations showed significant zone of inhibition (23–25 mm) against Staphylococcus aureus up to 1:128 dilutions while enterocin alone showed activity only up to 1:16 dilution. In the case of DPPH scavenging activity, a linear increase was observed from 0.007 to 1 mg/ml concentration of enterocin-SNPs which reached a maximum 96.55 ± 1.00% at 1 mg/ml concentration while by using enterocin alone at the same concentration maximum DPPH activity was 89.09 ± 0.07%. These overall results indicated enterocin-SNPs were durable and had significant antimicrobial, antibiofilm, and antioxidant activity.