TY - JOUR
T1 - Novel catabolic pathway for 4-Nitroaniline in a Rhodococcus sp. strain JS360
AU - Kurt, Zohre
AU - Qu, Yi
AU - Spain, Jim C
N1 - Copyright © 2023 Elsevier B.V. All rights reserved.
PY - 2023/7/15
Y1 - 2023/7/15
N2 - 4-Nitroaniline (4NA), the starting material for the first synthesized azo dye, is a toxic compound found in industrial wastewaters. Several bacterial strains capable of 4NA biodegradation were previously reported but the details of the catabolic pathway were not established. To search for novel metabolic diversity, we isolated a Rhodococcus sp. Strain JS360 by selective enrichment from 4NA-contaminated soil. When grown on 4NA the isolate accumulated biomass released stoichiometric amounts of nitrite and released less than stoichiometric amounts of ammonia, indicating that 4NA was used as sole carbon and nitrogen source to support growth and mineralization. Enzyme assays coupled with respirometry provided preliminary evidence that the first and second steps of 4NA degradation involve monooxygenase-catalyzed reactions followed by ring cleavage prior to deamination. Sequencing and annotation of the whole genome revealed candidate monooxygenases that were subsequently cloned and expressed in E.coli. Heterologously expressed 4NA monooxygenase (NamA) and 4-aminophenol (4AP) monooxygenase (NamB) transformed 4NA to 4AP and 4AP to 4-aminoresorcinol (4AR) respectively. The results revealed a novel pathway for nitroanilines and defined two monooxygenase mechanisms likely to be involved in the biodegradation of similar compounds.
AB - 4-Nitroaniline (4NA), the starting material for the first synthesized azo dye, is a toxic compound found in industrial wastewaters. Several bacterial strains capable of 4NA biodegradation were previously reported but the details of the catabolic pathway were not established. To search for novel metabolic diversity, we isolated a Rhodococcus sp. Strain JS360 by selective enrichment from 4NA-contaminated soil. When grown on 4NA the isolate accumulated biomass released stoichiometric amounts of nitrite and released less than stoichiometric amounts of ammonia, indicating that 4NA was used as sole carbon and nitrogen source to support growth and mineralization. Enzyme assays coupled with respirometry provided preliminary evidence that the first and second steps of 4NA degradation involve monooxygenase-catalyzed reactions followed by ring cleavage prior to deamination. Sequencing and annotation of the whole genome revealed candidate monooxygenases that were subsequently cloned and expressed in E.coli. Heterologously expressed 4NA monooxygenase (NamA) and 4-aminophenol (4AP) monooxygenase (NamB) transformed 4NA to 4AP and 4AP to 4-aminoresorcinol (4AR) respectively. The results revealed a novel pathway for nitroanilines and defined two monooxygenase mechanisms likely to be involved in the biodegradation of similar compounds.
KW - aniline compounds/metabolism
KW - biodegradation, environmental
KW - mixed function oxygenases/metabolism
KW - rhodococcus/metabolism
KW - anilineverbindingen/metabolisme
KW - biologische afbraak, milieu
KW - oxygenasen met gemengde functie/metabolisme
KW - rhodococcus/metabolisme
U2 - 10.1016/j.jhazmat.2023.131473
DO - 10.1016/j.jhazmat.2023.131473
M3 - Article
C2 - 37146325
SN - 0304-3894
VL - 454
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
M1 - 131473
ER -