SCREENING AND BIOSYNTHESIS OF SILVER NANOPARTICLE PRODUCING BIOFLOCCULANT AND ITS APPLICATION IN THE TREATMENT OF WASTEWATER SAMPLE

Abstract

Bioflocculants are biopolymers secreted by microbes like bacteria and fungi. They are capable of causing a phenomenon called; bioflocculation which is the clumping together of fine, dispersed and organic particles. The use of bacteria species for the purpose of bioflocculant production and synthesizing metallic NPs is due to high flocculation efficiency even at low concentrations and its ability to survive at higher concentration of metallic ions. In this study, a total of eleven (11) morphologically different bacteria were isolated. Morphological and biochemical characteristics of the selected bacteria isolate were investigated. The bacteria isolates were screened in kaolin suspension to determine their flocculating activities. Isolate RWN2 showed the highest flocculating activities, follow in order by isolate KWN4 and was identified as Bacillus sp. The effects of the physico-chemical parameters such as carbon sources, nitrogen sources and cations on bioflocculant production by isolate KWN4 and RWN2 at different incubation periods were evaluated. The visual observation, UV spectrum analysis, Fourier transform infrared spectroscopy (FTIR) analysis and the flocculating activities of the bacteria mediated nanoparticle was evaluated. Silver nanoparticle synthesized by Bacillus sp. KWN4 and Bacillus sp. RWN2 was confirmed by a color change from yellowish to brown, the highest absorbance peak in the UV spectrum analysis was recorded after 72 hrs showing a slight peak at 400 nm and the FTIR spectrum analysis showed 15 peaks which were present between 3762 cm−1 to 360 cm−1. The bioflocculants and biosynthesized silver nanoparticles was applied as a flocculating agent in the treatment of wastewater sample. This study has shown that Bacillus sp. KWN4 and Bacillus sp. RWN2 isolated from wastewater is a potential bioflocculant and nanoparticle producer which can be applied in the treatment of wastewater sample.