Catalytic oxidation of manganese(II) by multicopper oxidase CueO and characterization of the biogenic Mn oxide.
Manganese(II) contamination is naturally occurring in many groundwater and surface water sources. Moreover, industrial wastewater is also responsible for much of the Mn(II) contamination. Nowadays, Mn(II) contamination has become a serious environmental problem in some regions of the world. To explore a biological approach for removing excessive amounts of aqueous Mn(II) from water, we found a new biocatalyst multicopper oxidase CueO, which was firstly proved to catalyze the oxidation of Mn(II) both in vitro and in vivo. Subsequently, we established a CueO-mediated catalysis system to prepare biogenic Mn oxide (BioMnOx), which was confirmed to be γ-Mn3O4 by X-ray diffraction. This newly prepared BioMnOx consisted of 53.6% Mn(II), 18.4% Mn(III) and 28.0% Mn(IV) characterized by X-ray photoelectron spectroscopy. It exhibited distinct polyhedral structure with nanoparticles of 150-350 nm diameters observed by transmission electron microscopy. Importantly, CueO could remove 35.7% of Mn(II) after a seven-day reaction, and on the other hand, the cueO-overexpressing Escherichia coli strain (ECueO) could also oxidize 58.1% dissolved Mn(II), and simultaneously remove 97.7% Mn(II). Based on these results, we suggest that ECueO strain and CueO enzyme have potential applications on Mn(II) decontamination in water treatment.
State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China.
Jianmei
J
Su
State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China.
Lin
L
Deng
State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China.
Liangbo
L
Huang
State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China.
Shujin
S
Guo
Key Laboratory of Arable Land Conservation, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, Hubei, People's Republic of China.
Fan
F
Liu
State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, People's Republic of China. Electronic address: hejin@mail.hzau.edu.cn.
Jin
J
He
D002384:Catalysis; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D008345:Manganese / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*
D029968:Escherichia coli Proteins; D017895:Manganese Compounds; D010087:Oxides; D008345:Manganese; C027424:manganese oxide; D010088:Oxidoreductases; C499679:cueO protein, E coli
Biogenic Mn oxide; Mn(II) oxidation; Mn(II) removal; Multicopper oxidase CueO; γ-Mn(3)O(4)