Geraniol and geranial dehydrogenases induced in anaerobic monoterpene degradation by Castellaniella defragrans

Appl Environ Microbiol. 2012 Apr;78(7):2128-36. doi: 10.1128/AEM.07226-11. Epub 2012 Jan 27.


Castellaniella defragrans is a Betaproteobacterium capable of coupling the oxidation of monoterpenes with denitrification. Geraniol dehydrogenase (GeDH) activity was induced during growth with limonene in comparison to growth with acetate. The N-terminal sequence of the purified enzyme directed the cloning of the corresponding open reading frame (ORF), the first bacterial gene for a GeDH (geoA, for geraniol oxidation pathway). The C. defragrans geraniol dehydrogenase is a homodimeric enzyme that affiliates with the zinc-containing benzyl alcohol dehydrogenases in the superfamily of medium-chain-length dehydrogenases/reductases (MDR). The purified enzyme most efficiently catalyzes the oxidation of perillyl alcohol (k(cat)/K(m) = 2.02 × 10(6) M(-1) s(-1)), followed by geraniol (k(cat)/K(m) = 1.57 × 10(6) M(-1) s(-1)). Apparent K(m) values of <10 μM are consistent with an in vivo toxicity of geraniol above 5 μM. In the genetic vicinity of geoA is a putative aldehyde dehydrogenase that was named geoB and identified as a highly abundant protein during growth with phellandrene. Extracts of Escherichia coli expressing geoB demonstrated in vitro a geranial dehydrogenase (GaDH) activity. GaDH activity was independent of coenzyme A. The irreversible formation of geranic acid allows for a metabolic flux from β-myrcene via linalool, geraniol, and geranial to geranic acid.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyclic Monoterpenes
  • Alcaligenaceae / enzymology*
  • Alcaligenaceae / genetics
  • Alcaligenaceae / growth & development
  • Alcohol Oxidoreductases / genetics
  • Alcohol Oxidoreductases / metabolism*
  • Aldehyde Dehydrogenase / genetics
  • Aldehyde Dehydrogenase / metabolism*
  • Anaerobiosis
  • Culture Media
  • Escherichia coli / enzymology
  • Escherichia coli / genetics
  • Gene Expression Regulation, Bacterial*
  • Molecular Sequence Data
  • Monoterpenes / chemistry
  • Monoterpenes / metabolism*
  • Sequence Analysis, DNA
  • Terpenes / metabolism*


  • Acyclic Monoterpenes
  • Culture Media
  • Monoterpenes
  • Terpenes
  • Alcohol Oxidoreductases
  • Aldehyde Dehydrogenase
  • geraniol
  • citral

Associated data

  • GENBANK/FR669447