Identification of Iron Reducing Bacteria from Kaolin of Different Mining Sites in Northern Nigeria for Potential Bioleaching Activity

Abstract

Kaolin is a naturally occurring raw material for several industrial applications. Moreover, the economy of using Kaolin has some restrictions due to presence of iron-bearing impurities in form of oxides and hydroxides. This has a negative effect on the whiteness and refractoriness of some products and the production of high purity ceramics. The application of microbial leaching has been regarded as cheap and bio-friendly than conventional methods, hence this study investigates the isolation of potential iron reducing bacteria capable of providing efficient bioleaching. Bacteria isolation was carried out using serial dilution and plating techniquesResult of molecular, morphological and biochemical analyses reveal the presence of many bacterial isolates that includes Acinobacter spp., Aeromonas spp., Clostridium spp., Klebsiella spp., Pseudomonas spp. and Sporanaerobacter spp. Aeromonas and Sporanaerobacter species were identified as more closely related to the Pseudomonas and Geobacter species that are reported to be good iron reducing bacteria. This may suggest a possible candidate strain that could provide efficient bioleaching activity. Result of X-ray Fluorescence spectrometry of Kaolin prior to isolation and identification of indigenous bacteria was found to contain the following oxides; Fe₂O_3, SiO₂, A1₂O₃, MgO, P₂O_5, SO_3, TiO_2, MnO and CaO which confirmed the identity of Kaolin samples collected. The highest oxide was found to be SiO₂.