Hydrolytic Dechlorination of Chlorothalonil by Ochrobactrum sp CTN-11 Isolated from a Chlorothalonil-Contaminated Soil
Hydrolytic Dechlorination of Chlorothalonil by Ochrobactrum sp CTN-11 Isolated from a Chlorothalonil-Contaminated Soil
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DOI：
10.1007/s00284-010-9603-8
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发表时间：
2010-09-01
影响因子：
2.6
通讯作者：
Jiang, Jiandong
中科院分区：
文献类型：
--
作者：
Liang, Bin;Li, Rong;Jiang, Jiandong
从百菌清污染土壤中分离到一株能降解百菌清的细菌CTN-11。通过对菌株CTN-11的形态特征、生化特性和16 S rRNA基因的比较分析，确定该菌株为苍白杆菌属（Ochrobactrum sp.）。菌株CTN-11能在48 h内将50 mg l（-1）CTN降解至检测不到的水平，并能在20 ~ 40 A ℃和pH 6.0 ~ 9.0的较宽温度范围内有效降解CTN。新的分离物不同于那些先前报道的CTN共代谢降解剂，在没有其他碳源的情况下转化CTN。从人苍白杆菌（Ochrobactrum anthropi）SH 35 B中克隆了一个谷胱甘肽S-转移酶（GST）编码基因，其序列与人苍白杆菌SH 35 B的GST编码基因有88%的同源性。然而，该基因在谷胱甘肽的存在下没有功能性表达，表明CTN-11菌株中GST催化的硫解取代不能使CTN还原脱氯。利用串联质谱技术对CTN厌氧降解过程中产生的代谢产物羟基三氯氰（CTN-OH）进行了鉴定，证实了CTN的降解过程中存在水解脱氯作用。研究了菌株CTN-11在无菌和非无菌土壤中对CTN的去除效果。在两种土壤样品中，50 mg kg（-1）CTN可在3天内降解至检测不到的水平。本研究强调了一个重要的潜在用途的菌株CTN-11的清洁CTN污染的场地，并提出了一个水解脱氯反应的CTN的纯培养。
A bacterial strain, designated as CTN-11, capable of degrading chlorothalonil (CTN), was isolated from a chlorothalonil-contaminated soil in China. Based on the morphological, biochemical characteristics and comparative analysis of the 16S rRNA genes, strain CTN-11 was identified as Ochrobactrum sp. Strain CTN-11 could degrade 50 mg l(-1) CTN to a non-detectable level within 48 h, and efficiently degrade CTN in a relatively broad range of temperatures from 20 to 40A degrees C and initial pH values from 6.0 to 9.0. The new isolate differed from those previously reported CTN co-metabolic degraders by transforming CTN in the absence of other carbon sources. A glutathione S-transferase (GST) coding gene, which showed 88% sequence similarity with that from Ochrobactrum anthropi SH35B, was cloned from strain CTN-11. However, the gene was not functionally expressed in the presence of glutathione, indicating that CTN was not reductively dechlorinated by thiolytic substitution catalyzed by GST in strain CTN-11. The metabolite hydroxyl-trichloroisophthalonitrile (CTN-OH) produced during CTN anaerobic degradation was identified based on tandem MS/MS, confirming that hydrolytic dechlorination was involved in the CTN degradation. The removal of CTN by strain CTN-11 in sterile and non-sterile soils was also studied. In both soil samples, 50 mg kg(-1) CTN could be degraded to an undetectable level within 3 days. This study highlights an important potential use of strain CTN-11 for the cleanup of CTN-contaminated sites and presents a hydrolytic dechlorination reaction of CTN by a pure culture.