一株蒽降解细菌的分离及降解特性研究

【目的】从盐碱土壤中筛选蒽降解菌株并分析其降解特性。【方法】采用极度稀释结果流式细胞检测法筛选分离纯化菌株，通过16S rRNA基因序列分析对菌株进行初步鉴定，采用气质联用仪(GC-MS)分析蒽的降解特性。【结果】从盐碱土壤中筛选出一株高效蒽降解菌株。经过16S rRNA基因序列分析，鉴定该菌株为Demequina salsinemorus BJ1。菌株可以利用蒽作为唯一碳源生长，降解率可达92%。在一定浓度范围内，随着蒽浓度的降低，细菌生长速率变快，降解率升高。添加外加碳源后，细菌生长速率明显变快，而对蒽降解率变低。对萃取中间代谢产物的质谱分析表明，降解蒽的中间代谢产物主要有9,10-anthracenedione (9,10-蒽醌)和Phthalic acid (邻苯二甲酸)等，说明它可能通过邻苯二甲酸途径降解蒽。【结论】筛选得到一株新的耐盐碱蒽降解菌，该菌降解效率高，对修复石油污染的土壤有一定的现实意义。

Isolation and characterization of an anthracene degradation bacterial strain

Objective] We aimed to isolate anthracene-degrading bacterium from saline-alkli soil and analyze its degradation characteristics. Methods] Extinction dilution was used to isolate and purify the bacterium. Flow cytometry was applied to monitor bacterial growth. Anthracene and metabolites were analyzed by GC-MS. Results] An anthracene degrading bacterial strain was isolated from highly saline soil. Based on its 16S rRNA gene sequence analysis, the bacteria was identified as Demequina salsinemorus. It can use anthracene as sole carbon and energy source. The highest degradation efficiency was 92%. Within a certain concentration range, the bacterial growth rate became faster and the degradation rate increased when the concentration of anthracene was decreasing. After adding exotic carbon source, bacterial growth rate increased significantly. However, the degradation efficiency decreased. 9,10-anthracenedione and phthalic acid were identified as the major metabolites. The phthalic acid path way was proposed as the degradation pathway. Conclusion] A bacterial strain with a high anthracene-degrading efficiency was isolated. Our results may have important practical significance for petroleum-contaminated soil remediation.