title: Removal of multi-heavy metals using biogenic manganese oxides generated by a deep-sea sedimentary bacterium - Brachybacterium sp. strain Mn32.
abstract: A deep-sea manganese-oxidizing bacterium, Brachybacterium sp. strain Mn32, showed high Mn(II) resistance (MIC 55 mM) and Mn(II)-oxidizing/removing abilities. Strain Mn32 removed Mn(II) by two pathways: (1) oxidizing soluble Mn(II) to insoluble biogenic Mn oxides - birnessite (delta-MnO(2) group) and manganite (gamma-MnOOH); (2) the biogenic Mn oxides further adsorb more Mn(II) from the culture. The generated biogenic Mn oxides surround the cell surfaces of strain Mn32 and provide a high capacity to adsorb Zn(II) and Ni(II). Mn(II) oxidation by strain Mn32 was inhibited by both sodium azide and o-phenanthroline, suggesting the involvement of a metalloenzyme which was induced by Mn(II). X-ray diffraction analysis showed that the crystal structures of the biogenic Mn oxides were different from those of commercial pyrolusite (beta-MnO(2) group) and fresh chemically synthesized vernadite (delta-MnO(2) group). The biogenic Mn oxides generated by strain Mn32 showed two to three times higher Zn(II) and Ni(II) adsorption abilities than commercial and fresh synthetic MnO(2). The crystal structure and the biogenic MnO(2) types may be important factors for the high heavy metal adsorption ability of strain Mn32. This study provides potential applications of a new marine Mn(II)-oxidizing bacterium in heavy metal bioremediation and increases our basic knowledge of microbial manganese oxidation mechanisms.
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors.forename: Wenming
authors.initials: W
authors.lastname: Wang
authors.affiliation: The Third Institute of Oceanography, State Oceanic Administration, Xiamen 361005, PR China.
authors.forename: Zongze
authors.initials: Z
authors.lastname: Shao
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, PR China.
authors.forename: Gejiao
authors.initials: G
authors.lastname: Wang
mesh_terms: D001673:Biodegradation, Environmental; D019015:Geologic Sediments / Q000382:microbiology; D008345:Manganese / Q000737:chemistry / Q000378:metabolism; D017895:Manganese Compounds / Q000378:metabolism*; D019216:Metals, Heavy / Q000737:chemistry / Q000378:metabolism*; D008835:Micrococcaceae / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction / Q000187:drug effects; D010087:Oxides / Q000378:metabolism*; D010618:Phenanthrolines / Q000494:pharmacology; D011480:Protease Inhibitors / Q000494:pharmacology; D011868:Radioisotopes / Q000737:chemistry / Q000378:metabolism; D019810:Sodium Azide / Q000494:pharmacology; D014871:Water Microbiology; D014961:X-Ray Diffraction; D015033:Zinc Isotopes / Q000737:chemistry / Q000378:metabolism
chemical_list: D017895:Manganese Compounds; D019216:Metals, Heavy; D010087:Oxides; D010618:Phenanthrolines; D011480:Protease Inhibitors; D011868:Radioisotopes; D015033:Zinc Isotopes; D008345:Manganese; C027424:manganese oxide; D009532:Nickel; D019810:Sodium Azide; C025205:1,10-phenanthroline