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)