Hydrolytic dechlorination of chlorothalonil by Ochrobactrum sp. CTN-11 isolated from a chlorothalonil-contaminated soil.
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 40 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.
Liang
Bin
B
Department of Microbiology, Key Lab of Microbiological Engineering of Agricultural Environment, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, Jiangsu Province, People's Republic of China.
Li
Rong
R
Jiang
Dong
D
Sun
Jiquan
J
Qiu
Jiguo
J
Zhao
Yanfu
Y
Li
Shunpeng
S
Jiang
Jiandong
J
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015373:Bacterial Typing Techniques; D002681:China; D002713:Chlorine / Q000378:metabolism*; D003001:Cloning, Molecular; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009570:Nitriles / Q000378:metabolism*; D042041:Ochrobactrum / Q000145:classification* / Q000302:isolation & purification / Q000378:metabolism*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D012989:Soil Pollutants / Q000378:metabolism*; D013696:Temperature
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D009570:Nitriles; D012336:RNA, Ribosomal, 16S; D012989:Soil Pollutants; D002713:Chlorine; D005982:Glutathione Transferase; C005806:tetrachloroisophthalonitrile