硝酸盐依赖型铁氧化菌Aquabacterium olei HJ-4的分离鉴定及其功能特性

Isolation,Characterization and Function of a Nitrate-dependent Iron-oxidizing Bacterium Aquabacterium olei HJ-4

由微生物介导的铁氧化是自然界铁循环过程中至关重要的一部分。采用凝胶梯度管富集培养方法从湖北省潜江市汉江河岸带沉积物中分离筛选出一株能够利用硝酸盐作为电子受体氧化亚铁的新菌株,通过对其进行厌氧硝酸盐还原铁氧化动力学分析和菌种鉴定,并通过基因组测序数据对其蛋白编码基因进行功能注释,从多方面研究了该菌株的功能特性。结果表明:在厌氧、30℃、pH=7的环境中,该菌株在12 d内还原了96.7%的硝酸盐(3.6 mmol/L),Fe(Ⅱ)存在时可利用硝酸盐作为电子受体氧化亚铁,3.6 mmol/L亚铁的氧化率为11.3%;根据菌株的形态,结合系统发育分析,鉴定该菌株为水小杆菌,命名为Aquabacterium olei HJ-4;该菌株基因组中含有与铁代谢、氮代谢、砷酸盐还原和硝基还原相关的功能基因,表明其具有还原污染物的多种功能潜力。该菌株为微生物铁氧化耦合污染物的去除提供了可能的菌种资源。

Microbial-mediated iron oxidation is a crucial part of the iron cycle in nature.A new strain of ferrous iron oxidation using nitrate as an electron acceptor is isolated from the sediment of the Han River riparian zone in Qianjiang City,Hubei Province by a gradient tube enrichment culture method.The strain is characterized by anaerobic nitrate-reducing iron oxidation kinetics and strain identification,and functional annotation of its protein-encoded functional genes by genome sequencing data to investigate the functional properties of the strain from various aspects.The results show that in an anaerobic,30℃,pH=7 environment,the strain can reduce 96.7% nitrate(3.6 mmol/L) in 12 days.In the presence of Fe(Ⅱ),the strain can use nitrate as an electron acceptor to oxidize 11.3% ferrous iron(3.6 mmol/L).The strain is identified as Aquabacterium olei HJ-4 based on its morphology and phylogenetic analysis.The genome of the bacterium contains functional genes related to iron metabolism,nitrogen metabolism,arsenate reduction and iron reduction.The strain provides a possible microbial resource for iron oxidation coupled with pollutant removal.