Biodegradation of Di-(2-ethylhexyl) Phthalate by Rhodococcus ruber YC-YT1 in Contaminated Water and Soil

Int J Environ Res Public Health. 2018 May 11;15(5):964. doi: 10.3390/ijerph15050964.

Abstract

Di-(2-ethylehxyl) phthalate (DEHP) is one of the most broadly representative phthalic acid esters (PAEs) used as a plasticizer in polyvinyl chloride (PVC) production, and is considered to be an endocrine-disrupting chemical. DEHP and its monoester metabolites are responsible for adverse effects on human health. An efficient DEHP-degrading bacterial strain Rhodococcus ruber YC-YT1, with super salt tolerance (0⁻12% NaCl), is the first DEHP-degrader isolated from marine plastic debris found in coastal saline seawater. Strain YC-YT1 completely degraded 100 mg/L DEHP within three days (pH 7.0, 30 °C). According to high-performance liquid chromatography⁻mass spectrometry (HPLC-MS) analysis, DEHP was transformed by strain YC-YT1 into phthalate (PA) via mono (2-ethylehxyl) phthalate (MEHP), then PA was used for cell growth. Furthermore, YC-YT1 metabolized initial concentrations of DEHP ranging from 0.5 to 1000 mg/L. Especially, YC-YT1 degraded up to 60% of the 0.5 mg/L initial DEHP concentration. Moreover, compared with previous reports, strain YC-YT1 had the largest substrate spectrum, degrading up to 13 kinds of PAEs as well as diphenyl, p-nitrophenol, PA, benzoic acid, phenol, protocatechuic acid, salicylic acid, catechol, and 1,2,3,3-tetrachlorobenzene. The excellent environmental adaptability of strain YC-YT1 contributed to its ability to adjust its cell surface hydrophobicity (CSH) so that 79.7⁻95.9% of DEHP-contaminated agricultural soil, river water, coastal sediment, and coastal seawater were remedied. These results demonstrate that R. ruber YC-YT1 has vast potential to bioremediate various DEHP-contaminated environments, especially in saline environments.

Keywords: Rhodococcus ruber; biodegradation; bioremediation; di-(2-ethylhexyl) phthalate; marine plastic debris.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actinomycetales Infections
  • Biodegradation, Environmental
  • Diethylhexyl Phthalate / analysis*
  • Diethylhexyl Phthalate / chemistry*
  • Endocrine Disruptors / analysis*
  • Endocrine Disruptors / chemistry*
  • Environmental Pollution
  • Esters
  • Humans
  • Phthalic Acids / metabolism
  • Plasticizers
  • Polyvinyl Chloride
  • Rhodococcus*
  • Soil
  • Soil Microbiology
  • Water Microbiology
  • Water Pollution / analysis*

Substances

  • Endocrine Disruptors
  • Esters
  • Phthalic Acids
  • Plasticizers
  • Soil
  • phthalic acid
  • Polyvinyl Chloride
  • Diethylhexyl Phthalate