Phenotypic expression of Vogesella indigofera upon exposure to hexavalent chromium, Cr6+

J. D. Gu*, K. H. Cheung

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

21 Scopus citations


A eubacterium producing a blue pigment was isolated from a drinking water filter, and subsequently identified as Vogesella indigofera. This bacterium was further investigated for its morphological and biochemical characteristics after exposure to hexavalent chromium, Cr6+. The threshold Cr6+ concentration inhibiting the pigment production by V. indigofera was 200-300 μg ml-1 in liquid cultures of nutrient broth and 100-150 μg ml-1 on nutrient agar plates. The Cr6+ concentration preventing V. indigofera growth was 300-400 μg ml-1 in liquid cultures, but greater than 150 μg ml-1 on agar plates. Moreover, rugose colonies without the blue pigmentation were observed on agar plates amended with 150 (μg Cr6+) ml-1. The biochemical utilization profiles of the colonies without pigmentation did not differ from the original pigment-producing ones, indicating phenotypic plasticity of this bacterium. The difference of phenotypic expression of V. indigofera under various Cr6+ concentrations might have potential application as a pollution bioindicator for heavy metals.

Original languageEnglish
Pages (from-to)475-480
Number of pages6
JournalWorld Journal of Microbiology and Biotechnology
Issue number5
StatePublished - 2001
Externally publishedYes


  • Bioindicator
  • Chromium
  • Heavy metal
  • Phenotypic expression
  • Pigment production
  • Plasticity
  • Rugose colony
  • Vogesella indigofera


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