Establishment of a real-time PCR method for quantification of geosmin-producing Streptomyces spp. in recirculating aquaculture systems

Marc Auffret, Alexandre Pilote, Emilie Proulx, Daniel Proulx, Grant Vandenberg, Richard Villemur

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)


Geosmin and 2-methylisoborneol (MIB) have been associated with off-flavour problems in fish and seafood products, generating a strong negative impact for aquaculture industries. Although most of the producers of geosmin and MIB have been identified as Streptomyces species or cyanobacteria, Streptomyces spp. are thought to be responsible for the synthesis of these compounds in indoor recirculating aquaculture systems (RAS). The detection of genes involved in the synthesis of geosmin and MIB can be a relevant indicator of the beginning of off-flavour events in RAS. Here, we report a real-time polymerase chain reaction (qPCR) protocol targeting geoA sequences that encode a germacradienol synthase involved in geosmin synthesis. New geoA-related sequences were retrieved from eleven geosmin-producing Actinomycete strains, among them two Streptomyces strains isolated from two RAS. Combined with geoA-related sequences available in gene databases, we designed primers and standards suitable for qPCR assays targeting mainly Streptomyces geoA. Using our qPCR protocol, we succeeded in measuring the level of geoA copies in sand filter and biofilters in two RAS. This study is the first to apply qPCR assays to detect and quantify the geosmin synthesis gene (geoA) in RAS. Quantification of geoA in RAS could permit the monitoring of the level of geosmin producers prior to the occurrence of geosmin production. This information will be most valuable for fish producers to manage further development of off-flavour events.

Original languageEnglish
Pages (from-to)6753-62
Number of pages10
JournalWater Research
Issue number20
Publication statusPrint publication - 15 Dec 2011
Externally publishedYes

Bibliographical note

Copyright © 2011 Elsevier Ltd. All rights reserved.


  • Aquaculture
  • DNA, Bacterial/genetics
  • Genes, Bacterial/genetics
  • Molecular Sequence Data
  • Naphthols/metabolism
  • Phylogeny
  • Real-Time Polymerase Chain Reaction/methods
  • Streptomyces/genetics
  • Waste Disposal, Fluid


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