Department of Food and Environmental Sciences, University of Helsinki, PO Box 56, 00014 Helsinki, Finland.
Biotechnol Bioeng. 2011 Dec;108(12):2876-83. doi: 10.1002/bit.23267. Epub 2011 Aug 4.
Explosives used in mining, such as ammonium nitrate fuel oil (ANFO), can cause eutrophication of the surrounding environment by leakage of ammonium and nitrate from undetonated material that is not properly treated. Cold temperatures in mines affect nitrogen removal from water when such nutrients are treated with bioreactors in situ. In this study we identified bacteria in the bioreactors and studied the effect of temperature on the bacterial community. The bioreactors consisted of sequential nitrification and denitrification units running at either 5 or 10°C. One nitrification bioreactor running at 5°C was fed with salt spiked water. From the nitrification bioreactors, sequences from both ammonia- and nitrite-oxidizing bacteria were identified, but the species were distinct at different temperatures. The main nitrifiers in the lower temperature were closely related to the genera Nitrosospira and Candidatus Nitrotoga. 16S rRNA gene sequences closely related to halotolerant Nitrosomonas eutropha were found only from the salt spiked nitrification bioreactor. At 10°C the genera Nitrosomonas and Nitrospira were the abundant nitrifiers. The results showed that bacterial species richness estimates were low, <150 operational taxonomic units (OTUs), in all bioreactor clone libraries, when sequences were assigned to operational taxonomic units at an evolutionary distance of 0.03. The only exception was the nitrification bioreactor running at 10°C where species richness was higher, >300 OTUs. Species richness was lower in bioreactors running at 5°C compared to those operating at 10°C.
采矿中使用的炸药，如硝酸铵燃料油（ANFO），如果未经过适当处理的未爆炸材料中的铵和硝酸盐泄漏，会导致周围环境富营养化。当这种营养物质在现场用生物反应器处理时，矿山中的低温会影响氮从水中去除。在这项研究中，我们鉴定了生物反应器中的细菌，并研究了温度对细菌群落的影响。生物反应器由连续硝化和反硝化单元组成，分别在 5°C 和 10°C 下运行。一个在 5°C 下运行的硝化生物反应器用加盐的水进料。从硝化生物反应器中，鉴定出了氨氧化菌和亚硝酸盐氧化菌的序列，但在不同温度下，物种明显不同。在较低温度下的主要硝化菌与 Nitrosospira 和 Candidatus Nitrotoga 属密切相关。仅从加盐的硝化生物反应器中发现了与耐盐性 Nitrosomonas eutropha 密切相关的 16S rRNA 基因序列。在 10°C 时，Nitrosomonas 和 Nitrospira 属是丰富的硝化菌。结果表明，当将序列分配到进化距离为 0.03 的操作分类单位时，所有生物反应器克隆文库中的细菌物种丰富度估计值都较低，<150 个操作分类单位（OTUs）。唯一的例外是在 10°C 下运行的硝化生物反应器，其物种丰富度较高，>300 个 OTUs。与在 10°C 下运行的生物反应器相比，在 5°C 下运行的生物反应器中的物种丰富度较低。
