Mn(Ⅱ) Oxidation and Removal by a Manganese-oxidizing Bacterium Bacillus sp. MK3-1

Abstract:

Manganese-oxidizing microorganisms are able to oxidize soluble Mn(II) into insoluble Mn oxides. Such microorganisms are very useful in treatment of Mn-contaminated water. In this research, a Mn(II)- oxidizing bacterium Bacillus sp. MK3-1 was isolated from Mn-contaminated soil. This bacterium has high MnCl2 resistance with a MIC of 20 mmol/L. The results showed that it is able to oxidize and remove more than 96% of Mn(II) in the culture medium. The immobilized solid-embedding Bacillus sp. MK3-1can removed 87.12% of manganese contaminated water. The final concentration of MnCl2 after the treatment reached the national discharge standard level. Scan electron microscope observation showed that the produced Mn oxides located on the cell surfaces of Bacillus sp. MK3-1. Energy dispersive spectrdmeter analysis indicated that the content of manganese of cell surfaces of Bacillus sp. MK3-1 was 19.60% (W/W). At last we amplified a 903 bp multicopper oxidase gene mnxG encoding the putative Mn(II)-oxidizing protein. The product of mnxG showed 86% identity to the reported multicopper oxidase.