Complete mineralization of benzene by a methanogenic enrichment culture and effect of putative metabolites on the degradation
Complete mineralization of benzene by a methanogenic enrichment culture and effect of putative metabolites on the degradation
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DOI：
10.1016/j.chemosphere.2011.11.051
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发表时间：
2012-02-01
期刊：
影响因子：
8.8
通讯作者：
Furumai, Hiroaki
中科院分区：
文献类型：
--
作者：
Masumoto, Hiroki;Kurisu, Futoshi;Furumai, Hiroaki
厌氧条件下苯的微生物降解在污染场地的修复中发挥着重要作用，但对所涉及的微生物和代谢途径仍知之甚少。在这项研究中，我们评估了苯的降解甲烷富集培养获得非污染的莲花田土壤中，单独和存在的几个假定的代谢中间体，即甲苯，苯甲酸和苯酚。使用稳定的同位素（C-13-）标记的底物，苯被证明是几乎完全降解等摩尔浓度的甲烷和二氧化碳，没有可检测到的细胞外代谢产物的积累。同时，甲苯，苯甲酸和苯酚也有效地矿化，但可能是由微生物以外的苯降解。后者包括Hasda-A，其是存在于培养物中的推定苯降解δ变形杆菌。虽然甲苯和苯甲酸酯没有影响苯的降解，苯酚有中度的抑制作用，虽然它不是一个主要的代谢中间体的苯在我们的文化。最后，检测到4-羟基香豆素作为苯酚形成的化合物，但需要进一步的实验来阐明其与苯酚降解的关系。(C)2011爱思唯尔有限公司保留所有权利。
Microbial degradation of benzene under anaerobic conditions plays an important role in remediation of contaminated sites but the microorganisms and metabolic pathways involved remain poorly understood. In this study, we evaluated degradation of benzene by a methanogenic enrichment culture obtained from non-contaminated lotus field soil, alone and in the presence of several putative metabolic intermediates, that is, toluene, benzoate and phenol. Using stable isotope (C-13-) labeled substrate, benzene was shown to be degraded almost completely to equimolar concentrations of methane and carbon dioxide, without detectable accumulation of extracellular metabolites. Concurrently, toluene, benzoate and phenol were also effectively mineralized, but probably by microorganisms other than the benzene degraders. The latter included Hasda-A, which is putative benzene-degrading deltaproteobacterium present in the culture. While toluene and benzoate did not affect benzene degradation, phenol had a moderate inhibitory effect although it was not a major metabolic intermediate of benzene in our culture. Finally, 4-hydroxycoumarin was detected as a compound formed from phenol but further experiments are required to elucidate its relationship to degradation of phenol. (C) 2011 Elsevier Ltd. All rights reserved.