Anaerobic nitrate-dependent iron(II) oxidation by a novel autotrophic bacterium, Pseudomonas sp. SZF15

A novel Anaerobic Fe(II) Oxidizing Denitrifier (AFODN) strain SZF15 was isolated from the sediment of Tang Yu reservoir. Based on phenotypic and phylogenetic characteristics, the isolated strain was identified as Pseudomonas sp. Strain SZF15 was studied for characteristics of nitrate and Fe2+ removal. Results showed the strain had the capability to completely reduce 80.86% of NO3−-N and oxidize 75.53% of Fe2+ over 72 h at the anaerobic condition. Meanwhile, the oxidation rate of Fe2+ was 0.72 mg L−1 h−1. Furthermore, the effectiveness of various electron donors with stimulating denitrification was compared in this experiment. The results indicated that the most rapid nitrate removal rate was occurred in the presence of hydrogen gas. Besides, response surface methodology (RSM) analysis demonstrated that the maximum removal rate of nitrate occurred under the conditions with an initial pH of 6.63, C/N ratio of 5.14, temperature of 32.45 °C and Fe2+ concentration of 62.45 mg L−1.