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

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．

Key words:Keywords: biodegradation，Pseudomonas aeruginosa，long-chain n-alkanes，crude oil，bioremediation