一株来自大西洋表层海水的烷烃降解菌Gordonia sp.S14-10的分离鉴定及其降解相关特性的分析

摘要

[目的]本研究的目的是从大西洋表层海水分离筛选新的烷烃降解菌,了解其降解基因及降解特性,为 海洋石油污染的生物治理提供材料.[方法]以柴油与原油作为混合碳源从大西洋表层海水样品中富集、并分离筛选出降解能力较强的烷烃降解菌.根据16S rRNA基因和其看家基因secAJ序列确定其系统进化地位.分析了烷烃降解范围、表面活性剂产生能力及其他生理生化特性;利用已报道的兼并引物进行了烷烃羟化酶基因的PCR扩增及系统进化分析.[结果]分离筛选得到1株能够降解C_(10)(C_(36)直链烷烃的菌株s14-10.经16s rRNA基因序列系统发育分析表明它属于戈登氏菌属(Gordonia),与Gordonia terraeT 同源性为99.86%,但secAl序列相似度仅为93.69%,可能为戈登氏属的一个新种.从该菌株中扩增得到了烷烃单加氧酶alkB和P450基因片段,它们与菌株Gordonia sp.TF6相应的基因序列具有最高相似度,分别为88.76%和99.61%.该菌能够产生糖脂类生物表面活性剂,将发酵液的表面张力降低到31.6 mN/m.[结论]首次从大洋环境中发现了Gordonia属的烷烃降解菌,可能为该属的一个新种.菌株S14-10至少编码两套与烷烃降解相关的单加氧酶系统,对各种直链烷烃降解范围宽,能产表面活性剂,在海洋油溢污染的生物修复中有较好的应用前景.%[Objective]The aim of this study is to isolate novel and efficient hydrocarbon-degrading bacteria (HDBs) from pelagic ocean.[Methods]The surface water sample from Atlantic Ocean was enriched in NH medium with crude oihdiesel oil (in a ratio of 1:1) as the sole carbon source. HDBs were isolated and their degradation ability was tested in MMC medium,and further subjected to genotypic and phenotypic analysis. Polymerase chain reaction with degenerate primers was performed to detect the genes encoding integral-membrane non-heme iron monooxygenase (AlkB) and cytochrome P450 CYP153 family. Meanwhile, the production of biosurfactant was examined by surface tension measurement, then extracted and purified for component characterization.[Results]A hydrocarbon-degrading bacterium named S14-10 was obtained,which can utilize C_(10)～C_(36) as the sole carbon source. Analysis of 16S rRNA sequence showed that it belonged to Gordonia genus showing the highest similarity (99.86%) with type strain of Gordonia terrae, while secAl sequence showed a low identity only 93.69%. Furthermore,two genes alkB and CYP153 P450 were obtained with PCR, which had highest similarities 88.76%and 99.61% to that of Gordonia sp. TF6,respectively. In addition,strain S14-10 was found to produce glycolipid biosurfactant, which lowered the surface tension of water to 31.6 mN/m.[Conclusion]Strain S14-10 is possibly a novel species of Gordonia,and the first hydrocarbon-degrading bacterium isolated from open sea. It has potential in bioremediation of oil contaminated environment.