Roh Yul, Liu Shi V, Li Guangshan, Huang Heshu, Phelps Tommy J, Zhou Jizhong
Environmental Sciences Division, Oak Ridge National Laboratory, Tennessee 37831-6038, USA.
Appl Environ Microbiol. 2002 Dec;68(12):6013-20. doi: 10.1128/AEM.68.12.6013-6020.2002.
Five bacterial strains were isolated from anaerobic enrichment cultures that had originated from inoculations with samples collected from the deep subsurface environments of the millions-of-years-old, geologically and hydrologically isolated Piceance Basin in Colorado. Small-subunit rRNA gene-based analyses indicated that all of these bacteria were closely related to Thermoanaerobacter ethanolicus, with similarities of 99.4 to 99.5%. Three isolates (X513, X514, and X561) from the five bacterial strains were used to examine physiological characteristics. These thermophilic bacteria were able to use acetate, glucose, hydrogen, lactate, pyruvate, succinate, and xylose as electron donors while reducing Fe(III), cobalt(III), chromium(VI), manganese(IV), and uranium(VI) at 60 degrees C. One of the isolates (X514) was also able to utilize hydrogen as an electron donor for Fe(III) reduction. These bacteria exhibited diverse mineral precipitation capabilities, including the formation of magnetite (Fe(3)O(4)), siderite (FeCO(3)), rhodochrosite (MnCO(3)), and uraninite (UO(2)). The gas composition of the incubation headspace and the ionic composition of the incubation medium exerted profound influences on the types of minerals formed. The susceptibility of the thermophilic Fe(III)-reducing cultures to metabolic inhibitors specific for ferric reductase, hydrogenase, and electron transport indicated that iron reduction by these bacteria is an enzymatic process.
从厌氧富集培养物中分离出了5株细菌菌株，这些培养物源自接种了从科罗拉多州有数百万年历史、地质和水文条件隔绝的皮申斯盆地深部地下环境采集的样本。基于小亚基rRNA基因的分析表明，所有这些细菌都与嗜热栖热菌密切相关，相似度为99.4%至99.5%。从这5株细菌菌株中选取了3株分离株（X513、X514和X561）来检测其生理特性。这些嗜热细菌能够利用乙酸盐、葡萄糖、氢气、乳酸盐、丙酮酸盐、琥珀酸盐和木糖作为电子供体，同时在60摄氏度下还原Fe(III)、钴(III)、铬(VI)、锰(IV)和铀(VI)。其中一株分离株（X514）还能够利用氢气作为电子供体来还原Fe(III)。这些细菌表现出多样的矿物沉淀能力，包括形成磁铁矿（Fe₃O₄）、菱铁矿（FeCO₃）、菱锰矿（MnCO₃）和晶质铀矿（UO₂）。培养顶空的气体组成和培养基的离子组成对形成的矿物类型产生了深远影响。嗜热Fe(III)还原培养物对铁还原酶、氢化酶和电子传递特异性代谢抑制剂的敏感性表明，这些细菌的铁还原是一个酶促过程。
