基于功能基因表达的高氯酸盐与硝酸盐氮修复

为更好地研究环境中高氯酸盐离子(ClO-4)与硝酸盐氮(NO-3-N)混合污染的共同降解。选用pcrA、cld基因表征参与高氯酸盐降解的细菌,NirS基因表征反硝化细菌,16S rRNA基因表征整个细菌群落的活性。通过对高浓度硝酸盐氮与高氯酸盐混合污染降解体系内不同时间点不同种基因的表达分析,实时定量的反应复杂环境中混合污染物生物降解机理。结果表明,在外源添加足够的醋酸盐作为电子供体条件下,NO-3-N与ClO-4质量浓度比为5∶1时,硝酸盐氮的存在不会完全抑制ClO-4的降解,当NO-3-N降解完全时,可以加快ClO-4的降解过程。在有硝酸盐氮存在的混合降解体系内,pcrA和cld基因与ClO-4的浓度变化之间的相关性不是很高,证明该功能基因对复杂环境中特定生物群落的表征有一定局限性。

Perchlorate and nitrate-nitrogen bioremediation based on expression of functional genes

In order to further investigate the degradation of perchlorate(ClO₄^-) and nitrate-nitrogen (NO₃^--N) co-contaminants in environments.pcrA and cld,NirS genes,and 16S rRNA were used to characterize perchlorate reducing bacteria activity,denitrifying bacteria and total bacteria,respectively.The mechanism of biodegradation of mixed contaminants in complex environments was quantitatively illustrated by analyzing the varied genes in different phases in the presence of perchlorate and high-concentration NO₃^--N.The experimental results showed when NO₃^--N was present as a co-contaminant with ClO₄^-,under the condition of adding sufficient external acetate acting as an electron donor,NO₃^- did not completely inhibit the ClO₄^- reduction at a NO₃^--N to ClO₄^- ratio of 5:1 (mg/L:mg/L).NO₃^- promoted ClO₄^- reduction once the NO₃^- was completely removed.The correlations between pcrA and ClO₄^- concentration,and cld and ClO₄^- concentration were not very significant when NO₃^--N was existent in the mixed system,demonstrating the limitations of using the functional genes as a marker to characterize specific microbial communities in the multi-contamination systems.