Nanotechnology has become the most effective and rapidly developing field in the area of material science, and silver nanoparticles (AgNPs) are of leading interest because of their smaller size, larger surface area, and multiple applications. The use of plant sources as reducing agents in the fabrication of silver nanoparticles is most attractive due to the cheaper and less time-consuming process for synthesis. Furthermore, the tremendous attention of AgNPs in scientific fields is due to their multiple biomedical applications such as antibacterial, anticancer, and anti-inflammatory activities, and they could be used for clean environment applications. In this review, we briefly describe the types of nanoparticle syntheses and various applications of AgNPs, including antibacterial, anticancer, and larvicidal applications and photocatalytic dye degradation. It will be helpful to the extent of a better understanding of the studies of biological synthesis of AgNPs and their multiple uses.

In this study Bacillus amyloliquefaciens RK3 was isolated from a sugar mill effluent-contaminated soil and utilised to generate a potential polysaccharide with anti-Alzheimer’s activity. Traditional and molecular methods were used to validate the strain. The polysaccharide produced by B. amyloliquefaciens RK3 was purified, and the yield was estimated to be 10.35 gL⁻¹. Following purification, the polysaccharide was structurally and chemically analysed. The structural analysis revealed the polysaccharide consists of α-d-mannopyranose (α-d-Manp) and β-d-galactopyranose (β-d-Galp) monosaccharide units connected through glycosidic linkages (i.e., β-d-Galp(1→6)β-d-Galp (1→6)β-d-Galp(1→2)β-d-Galp(1→2)[β-d-Galp(1→6)]β-d-Galp(1→2)α-d-Manp(1→6)α-d-Manp (1→6)α-d-Manp(1→6)α-d-Manp(1→6)α-d-Manp). The scanning electron microscopy and energy-dispersive X-ray spectroscopy imaging of polysaccharides emphasise their compactness and branching in the usual tubular heteropolysaccharide structure. The purified exopolysaccharide significantly impacted the plaques formed by the amyloid proteins during Alzheimer’s disease. Further, the results also highlighted the potential applicability of exopolysaccharide in various industrial and pharmaceutical applications.