Isolation and characterization of carbendazim-degrading Rhodococcus erythropolis djl-11

PLoS One. 2013 Oct 1;8(10):e74810. doi: 10.1371/journal.pone.0074810. eCollection 2013.

Abstract

Carbendazim (methyl 1H-benzimidazol-2-yl carbamate) is one of the most widely used fungicides in agriculture worldwide, but has been reported to have adverse effects on animal health and ecosystem function. A highly efficient carbendazim-degrading bacterium (strain dj1-11) was isolated from carbendazim-contaminated soil samples via enrichment culture. Strain dj1-11 was identified as Rhodococcus erythropolis based on morphological, physiological and biochemical characters, including sequence analysis of the 16S rRNA gene. In vitro degradation of carbendazim (1000 mg·L(-1)) by dj1-11 in minimal salts medium (MSM) was highly efficient, and with an average degradation rate of 333.33 mg·L(-1)·d(-1) at 28°C. The optimal temperature range for carbendazim degradation by dj1-11 in MSM was 25-30°C. Whilst strain dj1-11 was capable of metabolizing cabendazim as the sole source of carbon and nitrogen, degradation was significantly (P<0.05) increased by addition of 12.5 mM NH4NO3. Changes in MSM pH (4-9), substitution of NH4NO3 with organic substrates as N and C sources or replacing Mg(2+) with Mn(2+), Zn(2+) or Fe(2+) did not significantly affect carbendazim degradation by dj1-11. During the degradation process, liquid chromatography-mass spectrometry (LC-MS) detected the metabolites 2-aminobenzimidazole and 2-hydroxybenzimidazole. A putative carbendazim-hydrolyzing esterase gene was cloned from chromosomal DNA of djl-11 and showed 99% sequence homology to the mheI carbendazim-hydrolyzing esterase gene from Nocardioides sp. SG-4G.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzimidazoles / metabolism*
  • Carbamates / metabolism*
  • Esterases / genetics
  • Esterases / metabolism
  • Hydrogen-Ion Concentration
  • Hydrolysis
  • Rhodococcus / enzymology
  • Rhodococcus / genetics
  • Rhodococcus / isolation & purification*
  • Rhodococcus / metabolism*
  • Temperature

Substances

  • Benzimidazoles
  • Carbamates
  • Esterases
  • carbendazim

Grants and funding

This work was supported by the grant 2010DFA32330 from the Ministry of Science and Technology of China (http://www.most.gov.cn), the grant 2012GNC11004 and Taishan Research Fellowship from Department of Science and Technology of Shandong province (http://www.sdstc.gov.cn/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.