Biosynthesis and bactericidal activity of silver nanoparticles (AgNPs) using cell-free bioflocculant from domestic wastewater bacterial consortium

Autor: Adebayo, E A, Kumi, E O, Ajibade, V O, Akinjo, A O, Abiola, O S, Raji, M A, Adepoju, Y, Oduoye, O T
Zdroj: IOP Conference Series: Materials Science and Engineering; March 2020, Vol. 805 Issue: 1 p012033-012033, 1p
Abstrakt: Water bodies are becoming contaminated by chemicals and harmful microorganisms like bacteria, which often cause serious illnesses and at times death. It is therefore pertinent to find a mean of purifying wastewaters and larger polluted water bodies. This research aimed at isolating bioflocculant-producing bacteria to synthesis silver nanoparticles (AgNPs) for water purification and antimicrobial activities. Wastewater was collected from eateries (sites A and B) around LAUTECH Ogbomoso; the bioflocculant-producing bacteria were isolated and characterized to species level using molecular tools and registered in the GenBank database. Kaolin (5 g/L) suspension was used to measure the flocculating activity of isolated organisms at an optical density (OD) of 550 nm. The cell-free bioflocculant was used to synthesize AgNPs and its potentials to reduce the microbial load of polluted water were evaluated. The isolated strains were characterized and identified as (A) Bacillus polymyxa(KY705398), Bacillusspecies (KY705399), Bacillus alvei(KY705400) and Bacillus subtilis(KY705401); (B) Klebsiella pneumoniae(KY706100), Providencia stuartii(KY706101), and Acinetobacterspecies (KY706102). The consortium organisms gave flocculating activity of 92.46% (A) and 60% (B). The UV-vis spectroscopy showed AgNPs with surface plasmon resonance at 570 nm and 460 nm for sites A and B respectively. FTIR peaks of AgNPs (A) (3525, 3284, and 1179 cm?1) and (B) (3611, 3307 and 2492 Cm?1), pointed to protein as both capping and stabilizing agents for the synthesized nanoparticles. Synthesized AgNPs exerted total reduction of microbial load in faecal polluted wastewater of 146 CFU/ml at a 10?5factor at a concentration of 20 ?g. The results obtained revealed that cell-free bioflocculant AgNPs has bactericidal activity and it could be used as efficient water purifying agent.
Databáze: Supplemental Index