铜绿假单胞菌SJTD-2降解长链烷烃与原油的特性

Isolation and characterization of Pseudomonas aeruginosa strain SJTD-2 for degrading long-chain n-alkanes and crude oil

摘要:

摘要:【目的】石油污染严重威胁生态系统和生物圈，微生物修复被认为是一种安全有效可代替物化方法来治理石油污染的办法。本文对我们从石油污染土壤中分离获得的一株可分解正烷烃和原油的革兰氏阴性菌SJTD-2的理化性质和降解效能进行了研究。【方法】利用菌株表型和生理性质、16S rRNA序列比较分析与进化树绘制，确定新分离菌株SJTD-2的种属;测定菌株SJTD-2的生长曲线，确定其利用不同长度烷烃和原油为单一碳源的效能;利用GC-MS检测烷烃类物质的残留量，确定菌株SJTD-2降解烷烃和原油SJTD-2的降解效率和降解周期。【结果】菌株表型与16S rRNA序列比较及进化树比对分析结果显示，菌株SJTD-2与假单胞菌属的亲缘关系十分接近，为铜绿假单胞菌。菌株SJTD-2 可有效分解C10到C26的中链和长链烷烃及原油，利用它们作为其单一碳源生长;该菌株对长链烷烃(C18－C22)的利用效果较中链烷烃好，其中正二十二烷被认为是其最佳碳源。48 h内，该菌株可完全降解500 mg/L正二十二烷;72h 后，2 g/L的正二十二烷可几乎被菌株全部分解利用。此外，菌株SJTD-2在7 d内可将2 g/L的原油分解88%以上。【结论】与现有其它烷烃降解菌相比，铜绿假单胞菌SJTD-2具有突出的长链烷烃与原油降解效能及耐受能力，该菌株的发现与研究将有助于烷烃降解机制的研究和环境修复的进程。

Abstract:

Abstract:［Objective］Oil pollution poses a severe threat to ecosystems，and bioremediation is considered as a safe and efficient alternative to physicochemical.［methods］ for eliminating this contaminant．In this study，a gram-negative bacteria strain SJTD-2 isolated from oil-contaminated soil was found capable of utilizing n-alkanes and crude oil as sole energy sources．The efficiency of this strain in degrading these pollutants was analyzed.［Methods］Strain SJTD-2 was identified on the basis of its phenotype，its physiological features，and a comparative genetic analysis using 16S rRNA sequence． Growth of strain SJTD-2 with different carbon sources (n-alkanes of different lengths and crude oil) was assessed，and the gas chromatography-mass spectrometry method was used to analyze the degradation efficiency of strain SJTD-2 for n-alkanes and petroleum by detecting the residual n-alkane concentrations.［Results］ Strain SJTD-2 was identified as Pseudomonas aeruginosa based on the phenotype，physiological features，and 16S rRNA sequence analysis．This strain can efficiently decompose medium-chain and long-chain n-alkanes (C10 -C26)，and petroleum as its sole carbon sources．It preferred the long-chain n-alkanes (C18 -C22)，and n-docosane was considered as the best carbon source for its growth．In 48 h，500 mg /L n-docosane could be degraded completely，and 2 g/L n-docosane was decomposed to undetectable levels within 72 h．Moreover，strain SJTD-2 could utilize about 88% of 2 g/L crude oil in 7days．Compared with other alkane-utilizing strains，strain SJTD-2 showed outstanding degradation efficiency for long-chain n-alkanes and high tolerance to petroleum at elevated concentrations．［Conclusion］The isolation and characterization of strain SJTD-2 would help researchers study the mechanisms underlying the biodegradation of n-alkanes，and this strain could be used as a potential strain for environmental governance and soil bioremediation．