TY - JOUR
T1 - Dissipation, dehalogenation, and denitration of chloroaromatic compounds by Nocardioides sp. strain PD653
T2 - Characterization of the substrate specificity
AU - Ito, Koji
AU - Takagi, Kazuhiro
AU - Kataoka, Ryota
AU - Kiyota, Hiromasa
AU - Iwasaki, Akio
N1 - Funding Information:
A selectivity of strain PD653 for highly chlorinated nitrobenzenes was shown in this experiment. On the other hand, lower dehalogenation activities were shown against chloronitroben-zenes as to decrease in halo substituents, particularly, strain PD653 poorly dehalogenated mono-and di-chlorinated nitrobenzenes. Despite the apparent dissipation of substrates, no chloride release was observed for 3,5-, 3,4-, 2,3-, and 2,5-dichloro-1-nitrobenzenes. This result indicates that an enzyme(s) other than dehalogenase attacks low chlorinated substrates. No chloride release was observed for 2,3,4,5-tetrachloro-1-nitrobenzene, despite the 7.0±0.4 µmol L−1 nitrate ion being liberated. A plausible reason for this might be the generation of a dead-end product, 2,3,4,5-tetrachlorophenol, via denitration. This hypothesis is supported by Fig. S1, showing the accumulation of putative 2,3,4,5-tetrachlorophenol in the sample supplemented with 2,3,4,5-tetrachloro-1-nitrobenzene. Compared to PCNB, HCB, and PCTA, PCA was degraded to a lesser extent, 53.1±9.8%. If an electron donating a –NH2 group on the benzene ring affects the degradation rate, from our data, one could hypothesize that strain PD653 cannot degrade substrates whose aromatic ring is activated by the electron-donating group. The inductive effects by substituents could be considered a key factor in determining whether strain PD653 recognizes aromatic compounds as substrates. Given that PCTA, PCA, and the impurity ingredient HCB have been detected in agricultural soil to which technical PCNB has been applied,23–25) it is of interest that strain PD653, which was isolated from PCNB-contaminated soil,17) exhibited substrate specificity toward each of those compounds.
Funding Information:
This work was supported by grants from JSPS Research Fellowship for Young Scientists (17J00825) and JSPS KAKENHI (grant no. 18H02319).
Publisher Copyright:
© Pesticide Science Society of Japan.
PY - 2019
Y1 - 2019
N2 - The substrate range of Nocardioides sp. strain PD653, capable of mineralizing hexachlorobenzene, was investigated based on the dissipation of substrates and the liberation of halogen ions. Strain PD653 dehalogenated 10 out of 18 halophenol congeners; however, it could dehalogenate only hexachlorobenzene out of seven halobenzene congeners tested. Moreover, dehalogenation activities were shown for chloronitrobenzenes, along with an increase in the number of substituted chlorine atoms except for 2,3,4,5-tetrachloro-1-nitrobenzene. These results suggested that this strain might be applicable to remediate soil contaminated with these persistent chloroaromatic compounds.
AB - The substrate range of Nocardioides sp. strain PD653, capable of mineralizing hexachlorobenzene, was investigated based on the dissipation of substrates and the liberation of halogen ions. Strain PD653 dehalogenated 10 out of 18 halophenol congeners; however, it could dehalogenate only hexachlorobenzene out of seven halobenzene congeners tested. Moreover, dehalogenation activities were shown for chloronitrobenzenes, along with an increase in the number of substituted chlorine atoms except for 2,3,4,5-tetrachloro-1-nitrobenzene. These results suggested that this strain might be applicable to remediate soil contaminated with these persistent chloroaromatic compounds.
KW - Aerobic biodegradation
KW - Dehalogenation
KW - Nocardioides sp. strain PD653
KW - Substrate. specificity
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U2 - 10.1584/jpestics.D19-024
DO - 10.1584/jpestics.D19-024
M3 - Article
AN - SCOPUS:85072670742
SN - 1348-589X
VL - 44
SP - 171
EP - 176
JO - Journal of Pesticide Sciences
JF - Journal of Pesticide Sciences
IS - 3
ER -