Bio-fabrication, Optimization and Characterization of Silver Nanoparticles Using Streptomyces sp. HDW7 and Nocardia sp. OX5 Bioflocculants; Flocculation and Antibacterial Efficiency

The challenges in wastewater treatment and the increasing scourge of waterborne diseases have necessitated the search for effective bioflocculating antimicrobials in nanoparticles. In this study, bioflocculants produced by Streptomyces sp. HDW7 and Nocardia sp. OX5 were used for AgNPs (SBAgNPs and NBAgNPs) biosynthesis. The AgNPs were characterized using UV-vis spectrophotometry, FTIR and SEM, and their flocculating and antibacterial activities evaluated. The bioflocculants bio-reduced AgNO3 to AgNPs and the surface plasmon resonance absorption peak was at 600 nm. 10 mM AgNO3, pH 3.0 and 9.0, and 45 o C supported the highest nanoparticles biosynthesis. FTIR spectra showed 21 and 23 peaks for the bioflocculants and were respectively reduced to 16 and 20 for SBAgNPs and NBAgNPs. The SBAgNPs and NBAgNPs were porous and anisotropic/irregular, with sizes of 9.5 nm and 11.8 nm, respectively. SBAgNPs and NBAgNPs had 86 and 71% flocculation efficiency in abattoir wastewater treatment and good antibacterial activity with a broad spectrum against Gram-positive and Gram-negative pathogens from water sources. The biosynthesized AgNPs can serve as potential flocculating and antibacterial agents in water purification and wastewater treatment.