Applied Microbiology and Biotechnology

, Volume 98, Issue 19, pp 8235–8252

Genetic and metabolic analysis of the carbofuran catabolic pathway in Novosphingobium sp. KN65.2

  • Thi Phi Oanh Nguyen
  • Damian E. Helbling
  • Karolien Bers
  • Tekle Tafese Fida
  • Ruddy Wattiez
  • Hans-Peter E. Kohler
  • Dirk Springael
  • René De Mot
Applied genetics and molecular biotechnology

DOI: 10.1007/s00253-014-5858-5

Cite this article as:
Nguyen, T.P.O., Helbling, D.E., Bers, K. et al. Appl Microbiol Biotechnol (2014) 98: 8235. doi:10.1007/s00253-014-5858-5

Abstract

The widespread agricultural application of carbofuran and concomitant contamination of surface and ground waters has raised health concerns due to the reported toxic effects of this insecticide and its degradation products. Most bacteria that degrade carbofuran only perform partial degradation involving carbamate hydrolysis without breakdown of the resulting phenolic metabolite. The capacity to mineralize carbofuran beyond the benzofuran ring has been reported for some bacterial strains, especially sphingomonads, and some common metabolites, including carbofuran phenol, were identified. In the current study, the catabolism of carbofuran by Novosphingobium sp. KN65.2 (LMG 28221), a strain isolated from a carbofuran-exposed Vietnamese soil and utilizing the compound as a sole carbon and nitrogen source, was studied. Several KN65.2 plasposon mutants with diminished or abolished capacity to degrade and mineralize carbofuran were generated and characterized. Metabolic profiling of representative mutants revealed new metabolic intermediates, in addition to the initial hydrolysis product carbofuran phenol. The promiscuous carbofuran-hydrolyzing enzyme Mcd, which is present in several bacteria lacking carbofuran ring mineralization capacity, is not encoded by the Novosphingobium sp. KN65.2 genome. An alternative hydrolase gene required for this step was not identified, but the constitutively expressed genes of the unique cfd operon, including the oxygenase genes cfdC and cfdE, could be linked to further degradation of the phenolic metabolite. A third involved oxygenase gene, cfdI, and the transporter gene cftA, encoding a TonB-dependent outer membrane receptor with potential regulatory function, are located outside the cfd cluster. This study has revealed the first dedicated carbofuran catabolic genes and provides insight in the early steps of benzofuran ring degradation.

Keywords

Methylcarbamate Sphingomonad Proteomics Metabolites cfd genes 

Supplementary material

253_2014_5858_MOESM1_ESM.pdf (905 kb)
ESM 1(PDF 905 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Thi Phi Oanh Nguyen
    • 1
    • 2
  • Damian E. Helbling
    • 3
  • Karolien Bers
    • 1
  • Tekle Tafese Fida
    • 1
  • Ruddy Wattiez
    • 4
  • Hans-Peter E. Kohler
    • 3
  • Dirk Springael
    • 1
  • René De Mot
    • 5
  1. 1.Division of Soil and Water Management, Department of Earth and Environmental SciencesKU LeuvenLeuvenBelgium
  2. 2.Department of Biology, College of Natural SciencesCan Tho UniversityCan ThoVietnam
  3. 3.Department of Environmental MicrobiologySwiss Federal Institute of Aquatic Science and Technology (EAWAG)DübendorfSwitzerland
  4. 4.Department of Proteomics and Microbiology, Research Institute for BiosciencesUniversity of MonsMonsBelgium
  5. 5.Centre of Microbial and Plant GeneticsKU LeuvenLeuvenBelgium
  6. 6.School of Civil and Environmental EngineeringCornell UniversityIthacaUSA
  7. 7.Department of Civil and Chemical EngineeringGeorgia Institute of TechnologyAtlantaUSA