Cr(VI) resistance and removal by indigenous bacteria isolated from chromium-contaminated soil

J Microbiol Biotechnol. 2013 Aug;23(8):1123-32. doi: 10.4014/jmb.1301.01004.

Abstract

The removal of toxic Cr(VI) by microorganisms is a promising approach for Cr(VI) pollution remediation. In the present study, four indigenous bacteria, named LY1, LY2, LY6, and LY7, were isolated from Cr(VI)-contaminated soil. Among the four Cr(VI)-resistant isolates, strain LY6 displayed the highest Cr(VI)-removing ability, with 100 mg/l Cr(VI) being completely removed within 144 h. It could effectively remove Cr(VI) over a wide pH range from 5.5 to 9.5, with the optimal pH of 8.5. The amount of Cr(VI) removed increased with initial Cr(VI) concentration. Data from the time-course analysis of Cr(VI) removal by strain LY6 followed first-order kinetics. Based on the 16S rRNA gene sequence, strain LY6 was identified as Pseudochrobactrum asaccharolyticum, a species that had never been reported for Cr(VI) removal before. Transmission electron microscopy and energy dispersive X-ray spectroscopy analysis further confirmed that strain LY6 could accumulate chromium within the cell while conducting Cr(VI) removal. The results suggested that the indigenous bacterial strain LY6 would be a new candidate for potential application in Cr(VI) pollution bioremediation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brucellaceae / classification
  • Brucellaceae / genetics
  • Brucellaceae / isolation & purification
  • Brucellaceae / metabolism*
  • Chromium / metabolism*
  • Chromium / toxicity*
  • Cluster Analysis
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / genetics
  • DNA, Ribosomal / chemistry
  • DNA, Ribosomal / genetics
  • Drug Resistance, Bacterial*
  • Microscopy, Electron, Transmission
  • Molecular Sequence Data
  • Phylogeny
  • RNA, Ribosomal, 16S / genetics
  • Sequence Analysis, DNA
  • Soil Microbiology*
  • Soil Pollutants / metabolism*
  • Soil Pollutants / toxicity*
  • Spectrometry, X-Ray Emission

Substances

  • DNA, Bacterial
  • DNA, Ribosomal
  • RNA, Ribosomal, 16S
  • Soil Pollutants
  • Chromium
  • chromium hexavalent ion