Biogenesis of Bacterial and Fungal Endophytic Mediated Silver Nanoparticles

Abstract

Aim: Nanoparticles play an important role in developing materials that are light, effective, and eco-friendly with diverse applications. In this study, bacterial and fungal endophytes were screened for the synthesis of AgNPs.Materials and Methods: Endophytes for the biogenesis of nanoparticles were isolated from various explants. Selected bacterial and fungal endophytes were identified by 18s rRNA and 16s rRNA sequencing. Endophyte-mediated silver nanoparticles were characterized using different techniques like UV/Visible spectroscopy, XRD, HRTEM, DLS, EDX, and FTIR.Results: Optimization of AgNP synthesis by the endophytic bacterial isolate Bacillus cereus showed an optimum 5 mM silver nitrate concentration, a reaction mixture temperature of 37-40°C, a reaction time of 30 min, and PVP as a stable surfactant. Characterization carried out using advanced analytical instrumentation showed a sharp peak at 424 nm by UV/Visible spectroscopy. According to XRD and HR-TEM data analyzed, it was observed that the average size of AgNP was 12.4 and 12.9 nm, respectively. DLS and zeta potential showed the nanoparticles are dispersed evenly. FTIR analysis confirmed coating with primary and secondary amino acids, which is responsible for the stability of nanoparticles. EDX confirmed the elemental composition of silver nanoparticles.Conclusion: Synthesized nanoparticles are uniform in size, eco-friendly, have good biocompatibility, are easy to process, and are stable. We can further study potential biological activity such as plant growth promotion, nano-pesticide encapsulations, antifungal, antibacterial, antioxidant, and cytotoxicity of these synthesized AgNPs.

Keywords: DLS; FTIR; HRTEM; Silver nanoparticles; XRD