Novel simultaneous Fe(iii) reduction and ammonium oxidation of Klebsiella sp. FC61 under the anaerobic conditions

Abstract

A simultaneous Fe(III) reduction and ammonium oxidation of strain FC61 was isolated from the Tang Yu oligotrophic reservoir of Xi'an (China). Strain FC61 was identified to be a species of Klebsiella sp. The Fe(III) source and carbon source were optimized as Fe(III)-citrate and glucose in the study, and it could not only reduce Fe(III), but also remove NH₄⁺-N under anaerobic conditions. The results showed that more than 75% of NH₄⁺-N was removed after 36 h. Furthermore, the reducing ratio of Fe(III) was approximately 95% by 32 h at 30 °C. The optimal conditions of strain FC61 was observed at pH of 6.0, inoculation of 10% (v/v), C/N ratio of 6 and temperature of 30 °C. This study proved that the strain FC61 had the notable capability of simultaneous Fe(III) reduction and ammonium oxidation under the anaerobic conditions.