Simultaneous Removal of Mn(II) and Nitrate by the Manganese-Oxidizing Bacterium Acinetobacter sp. SZ28 in Anaerobic Conditions

A novel bacterium, strain SZ28, identified as Acinetobacter sp., showed anaerobic denitrification ability using Mn(II) as the electron donor. Nitrate-nitrogen concentration decreased from nearly 16.52–mg L−1 to 4.4–mg L−1, without accumulation of nitrite as an intermediate, with a maximum of 0.063–mg NO3−-N L−1 h−1, reaching a peak of 0.085–mg NO3−-N L−1 h−1 in sodium acetate. The nitrate removal rate reached 0.067–mg NO3−-N L−1 h−1, 0.059–mg NO3−-N L−1 h−1, and 0.078 mg NO3−-N L−1 h−1 using Mn(II), S(II), and Fe(II) as electron donors, respectively. The optimum pH was 6.0, with a removal rate of 0.063–mg NO3−-N L−1 h−1