Abstract

In this study, two newly isolated 2,4-dichlorophenol(2,4-DCP)-degrading strains, Pseudomonas sp. KZNSA (PKZNSA) and Klebsiella pneumoniae KZNSA (KpKZNSA), were enriched from an activated sludge sample with a known history of contamination with chlorinated organic compounds collected from a wastewater treatment plant located in Durban, South Africa. The strains could use 2,4-DCP as sole carbon and energy source. PKZNSA and KpKZNSA degraded 64 and 49% of 2,4-DCP, with the degradation rate constant of 0.14 and 0.03 mg/L d, respectively. Both PKZNSA and KpKZNSA were found to harbor the catabolic genes that encode the enzymes involved in 2,4-DCP degradation via the ortho-pathway which is further confirmed by the specific enzyme activity assays. The strains did not possess genes that encode the enzyme maleylacetate reductase, which is involved in funneling the last intermediate (maleylacetate) in the pathway into the Krebs cycle. Findings from this study will be helpful in the exploitation of these microorganisms and/or their enzymes in developing bioremediation strategies for the chlorophenol-polluted environment.

中文翻译：

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2,4-二氯苯酚被土著假单胞菌降解。PKZNSA 和肺炎克雷伯菌 KpKZNSA：动力学、酶活性和分解代谢基因检测

摘要

在这项研究中，两个新分离的 2,4-二氯苯酚 (2,4-DCP) 降解菌株Pseudomonas sp。KZNSA ( P KZNSA) 和肺炎克雷伯菌KZNSA ( Kp KZNSA) 从活性污泥样品中富集，该样品具有已知的氯化有机化合物污染历史，这些样品是从位于南非德班的废水处理厂收集的。这些菌株可以使用 2,4-DCP 作为唯一的碳源和能源。P KZNSA 和Kp KZNSA 降解 2,4-DCP 的 64% 和 49%，降解速率常数分别为 0.14 和 0.03 mg/L d。这两个P KZNSA和的Kp发现 KZNSA 含有编码通过邻位途径参与 2,4-DCP 降解的酶的分解代谢基因，具体酶活性测定进一步证实了这一点。这些菌株不具有编码马来酰乙酸还原酶的基因，该酶参与将通路中的最后一个中间体（马来酰乙酸）输送到三羧酸循环中。这项研究的结果将有助于开发这些微生物和/或它们的酶，以开发氯酚污染环境的生物修复策略。