World Journal of Microbiology and Biotechnology

, Volume 28, Issue 5, pp 2221–2228

Identification of a copper-responsive promoter and development of a copper biosensor in the soil bacterium Achromobacter sp. AO22

Original Paper

DOI: 10.1007/s11274-012-1029-y

Cite this article as:
Ng, S.P., Palombo, E.A. & Bhave, M. World J Microbiol Biotechnol (2012) 28: 2221. doi:10.1007/s11274-012-1029-y


A number of human activities result in environmental contamination with copper compounds that can cause severe detrimental effects on the ecosystem as well as human health. The physico-chemical methods of metal detection have limitations such as inability to distinguish between total versus bio-available metals and differences in metal uptake in different organisms. The heavy metal resistance-encoding genetic systems of certain bacteria provide critical tools for development of biosensors for these purposes. This study reports a copper biosensor utilizing the cop operon of the heavy metal resistant bacterial isolate, Achromobacter sp. AO22, isolated from a contaminated site in Australia. A section located between the divergently transcribed putative response regulator gene copR and multicopper oxidase gene copA that included a palindromic cop box was identified as a copper-responsive promoter using a lacZ reporter construct, pCOPRP, in E. coli. The expression was found to be enhanced by inclusion of copR. Another engineered strain, AO22(pCOPRP), showed stronger induction, and the lacZ expression in both backgrounds was enhanced significantly (250–400 fold) by copper but minimally by other metals. The construct in Achromobacter sp. AO22 thus has a high potential as biosensor for detecting copper bioavailability (hence potential toxicity) in a soil bacterial background, while the construct in E. coli is ideal for laboratory-based testing.


Heavy metalsCopperCop operoncop boxTwo-component signal transductionBiosensors

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Shee Ping Ng
    • 1
    • 2
  • Enzo A. Palombo
    • 1
  • Mrinal Bhave
    • 1
  1. 1.Environment and Biotechnology Centre, Faculty of Life and Social SciencesSwinburne University of TechnologyMelbourneAustralia
  2. 2.School of Science and TechnologyNilai University CollegePutra Nilai, Negeri SembilanMalaysia