The biological reduction rate of Fe(III) was studied using dissimilatory ferric reducing bacterial cultures (FeRB) in an attempt to establish a biotechnological via for the metallurgical treatment of iron ores. Enrichment cultures of dissimilatory ferric reducers were obtained from samples collected from a flooded acidic open pit in an abandoned Pb and Zn sulphide mining site nearby La Unión (Murcia, Spain). Adapted cultures were able to reduce 3 g/L of soluble Fe(III) with 100 efficiency in 36 hours. The growth of mixed cultures was also tested in solids. Ferrihydrite and ammonium jarosite served as electron acceptors in cultures where lactate acted as electron donor. Bacterial growth was also positive in both cases. This result represents an effective alternative to the chemical reduction of ferric minerals that avoids extreme temperatures when pyrometallurgical reactors are used. In addition, three species of FeRB were isolated and identified as Serratia fonticola, Aeromonas hydrophila and Clostridium celerecrescens. One of them, Aeromonas hydrophila, results of particular interest and, at the present moment, is being studied in depth. The particular significance of Aeromonas hydrophila is related to the characteristics of its exhausted cultures, where ferrous iron remains solved at pH values next to 7. At the present moment, the identification and characterization of the Fe(II) soluble complex is being account.
Isolation, Identification and Characterization of Some Bacteria from Soil Samples of Agbaja Iron Ore Mining Site of Kogi State