锰氧化菌Bacillus sp. MK3-1的Mn(Ⅱ)氧化特性和除锰能力研究

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

摘要:

锰氧化微生物能够将可溶的Mn(II)氧化为不溶的锰氧化物沉淀, 因此在生物除锰研究上具有重要的应用价值。本研究从锰污染土壤中分离到一株锰氧化菌Bacillus sp. MK3-1, 该菌对MnCl2有较高抗性, 其最低抑制浓度(Minimal inhibitory concentration, MIC)为20 mmol/L。实验表明该菌在培养基中Mn(Ⅱ)的去除率高达96%, 同时将其制成固体包埋菌剂应用于含0.15 mmol/L的MnCl2水溶液实验, 结果表明其仍然具有稳定的除锰能力, 去除率为87.12%, 使溶液的终锰浓度符合国家排放标准。扫描电子显微镜观察和能谱分析实验表明, 实验产生的锰氧化物均匀地分布在Bacillus sp. MK3-1的细胞表面, 细胞表面含锰量为19.60% (W/W)。用简并引物扩增目前被认为催化锰氧化的多铜氧化酶基因mnxG, 获得了903 bp的基因片段, 其基因产物与已报道的多铜氧化酶具有86%的同源性。

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.