Screening for Bio-flocculant Producing Bacterial Strains from Asa River in Ilorin Kwara State

Abstract Synthetic flocculants in water treatment have been reported to be detrimental to both human health and the environment. Thus, there is a constant search for bio-flocculants that is safe and addresses the effects of synthetic polymers. This study was aimed at isolating bacteria with bio-flocculating potential, their molecular identification and phylogenetic relatedness, and the optimization of their flocculating abilities from an open water (Asa River) in Ilorin Kwara State. The effect of carbon source (glucose, lactose and starch), cations (FeSO4, KCl and CaCl2) and pH (2 to 12) was evaluated on the bio-flocculating activities of the isolates using kaolin clay. The seven (7) novel (new strains) isolates with their respective accession number from National Center for Biotechnology Information (NCBI) after molecular confirmation are Pseudomonas otitidis MTK01 (MK263227), Aeromonas caviea MTK02 (MK263228), Providencia alcalifaciens MTK03 (MK263229), Providencia sp. MTK05 (MK263230), Alcaligenes sp. MTK06 (MK263231), Klebsiella pneumoniae MTK07 (MK263232) and Klebsiella sp. MTK08 (MK263233) while Raoultella ornithinolytica MTK04 was also identified. Phylogenetic tree of relatedness showed close kin of the isolates to established bacteria sequence deposited at the NCBI GenBank. Although the flocculating rate of each isolates varied with different parameters that was used in the study, glucose was the most supportive followed by lactose and starch, CaCl2 was most supportive cation followed by KCl and FeSO4 while pH 12, 6, 8, 10, 2 and 4 were the order of decreasing flocculating rate of the medium. This study has reported the presence of eight (8) bio-flocculating bacteria (out of which 7 are new strains of bacteria) in an open water which has been further optimized for effective flocculating rate and thus provides an ecofriendly and harmless flocculants source that can be employed in water treatment procedures.