Biodegradation of di-(2-ethylhexyl) phthalate by a halotolerant consortium LF

PLoS One. 2018 Oct 15;13(10):e0204324. doi: 10.1371/journal.pone.0204324. eCollection 2018.

Abstract

A halotolerant bacterial consortium capable of degrading di-(2-ethylhexyl) phthalate (DEHP) was enriched from activated sludge. Community analysis revealed that LF contained seven families and seven genera of bacteria. The predominant species was Gordonia sp. (54.93%), Rhodococcus. sp. (9.92%) and Achromobacter sp. (8.47%). The consortium could degrade 93.84% of 1000 mg/l DEHP after 48 h incubation. The optimal temperature and pH for LF to degrade DEHP were 30 °C and 6.0, respectively. LF degraded more than 91% of DEHP with salt concentrations ranging from 0-3%. The inoculum size had great effects on DEHP degradation (incubation time < 24h). LF could degrade high concentrations of DEHP (from 100 to 2000 mg/l) with the degradation ratio above 92% after 72 h incubation. Kinetics analysis revealed that the degradation of DEHP by LF was best fitted by the first-order kinetics when the initial concentration ranged from 100 to 2000 mg/l. The main intermediates (2-ethylhexyl pentyl phthalate, butyl (2-ethylhexyl) phthalate (BEHP), mono-ethylhexyl phthalate (MEHP), mono-hexyl phthalate (MHP), mono-butyl phthalate (MBP)) in DEHP degradation process were identified using gas chromatography-mass spectrometry (GC-MS), and a new complex biochemical pathway was proposed. Furthermore, LF could also degrade dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DBP), di-n-octyl phthalate (DOP) and phthalic acid (PA).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Achromobacter / metabolism
  • Biodegradation, Environmental*
  • Diethylhexyl Phthalate / metabolism*
  • Gas Chromatography-Mass Spectrometry
  • Gordonia Bacterium / metabolism
  • Hydrogen-Ion Concentration
  • Kinetics
  • Microbial Consortia / physiology*
  • Rhodococcus / metabolism
  • Salinity
  • Salt Tolerance*
  • Sewage / microbiology
  • Sodium Chloride / chemistry
  • Temperature

Substances

  • Sewage
  • Sodium Chloride
  • Diethylhexyl Phthalate

Grant support

This work was supported by a grant from the National Natural Science Foundation of China (51704093, 41430637 and 21571051); Opening Foundation of the Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha, 410083, China (No. 2015CNERC-CTHMP-); Program for Innovative Research Team (in Science and Technology) in University of Henan Province (16IRTSTHN012).