Geraniol and Geranial Dehydrogenases Induced in Anaerobic Monoterpene Degradation by Castellaniella defragrans

Abstract

<jats:title>ABSTRACT</jats:title><jats:p><jats:named-content content-type="genus-species">Castellaniella defragrans</jats:named-content>is a<jats:named-content content-type="genus-species">Betaproteobacterium</jats:named-content>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 (<jats:italic>geoA</jats:italic>, for<jats:italic>ge</jats:italic>raniol<jats:italic>o</jats:italic>xidation pathway). The<jats:named-content content-type="genus-species">C. defragrans</jats:named-content>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 (<jats:italic>k</jats:italic><jats:sub>cat</jats:sub>/<jats:italic>K</jats:italic><jats:sub>m</jats:sub>= 2.02 × 10<jats:sup>6</jats:sup>M<jats:sup>−1</jats:sup>s<jats:sup>−1</jats:sup>), followed by geraniol (<jats:italic>k</jats:italic><jats:sub>cat</jats:sub>/<jats:italic>K</jats:italic><jats:sub>m</jats:sub>= 1.57 × 10<jats:sup>6</jats:sup>M<jats:sup>−1</jats:sup>s<jats:sup>−1</jats:sup>). Apparent<jats:italic>K</jats:italic><jats:sub>m</jats:sub>values of &lt;10 μM are consistent with an<jats:italic>in vivo</jats:italic>toxicity of geraniol above 5 μM. In the genetic vicinity of<jats:italic>geoA</jats:italic>is a putative aldehyde dehydrogenase that was named<jats:italic>geoB</jats:italic>and identified as a highly abundant protein during growth with phellandrene. Extracts of<jats:named-content content-type="genus-species">Escherichia coli</jats:named-content>expressing<jats:italic>geoB</jats:italic>demonstrated<jats:italic>in vitro</jats:italic>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.</jats:p>

Whole‐cell‐based CYP153A6‐catalyzed (S)‐limonene hydroxylation efficiency depends on host background and profits from monoterpene uptake via AlkL

“…Such multistep oxidations are common for oxygenases (Bühler and Schmid, 2004; Guengerich et al, 2011) and examples include the oxidation of amorpha‐4,11‐diene to artemisinic acid by CYP71AV1 (Ro et al, 2006) and of ent ‐kaurene to ent ‐kaurenoic acid by CYP701A3 (Helliwell et al, 1999). Perillyl alcohol oxidation may also be catalyzed by strain‐intrinsic enzymes, as it was reported, for example, for the geraniol dehydrogenase of Castellaniella defragrans (Lüddeke et al, 2012). Several P. putida strains have been reported to convert limonene to perillic acid, for example, P. putida PL (Dhavalikar and Bhattacharyya, 1966), P. putida GS1 (Speelmans et al, 1998), and P. putida DSM12264 (Mirata et al, 2009).…”

Anaerobic Activation of p -Cymene in Denitrifying Betaproteobacteria: Methyl Group Hydroxylation versus Addition to Fumarate

“…Two further specifically formed proteins in p-cymene-adapted cells of "A. aromaticum" pCyN1 are homologs (Ͼ70% sequence identities) of recently described geraniol (GeoA) and geranial dehydrogenase (GeoB) from anaerobically monoterpene-degrading Castellaniella defragrans 65Phen (57) and are suggested to oxidize 4-isopropylbenzyl alcohol via the aldehyde intermediate to 4-isopropylbenzoate (enzymes from "A. aromaticum" pCyN1 termed Iod and Iad for 4-isopropylbenzyl alcohol and 4-isopropylbenzaldehyde dehydrogenase, respectively). Notably, GeoA of C. defragrans 65Phen also converts 4-isopropylbenzyl alcohol (57).…”

“…Notably, GeoA of C. defragrans 65Phen also converts 4-isopropylbenzyl alcohol (57). Finally, the identified putative CoA ligase (termed Ibl) could catalyze formation of CoA-activated 4-isopropylbenzoate prior to further degradation.…”

Hydrosols of orange blossom ( Citrus aurantium ), and rose flower ( Rosa damascena and Rosa centifolia ) support the growth of a heterogeneous spoilage microbiota

“…Moreover P. putida can use geraniol (or citronellol) as the sole carbon source (Vandenbergh & Cole, 1986;Vandenbergh & Wright, 1983). Similarly the bacterium Castellaniella defragrans converts geraniol into geranic acid using a geraniol and geranial dehydrogenase, with a gain of two NADH molecules (Lüddeke et al, 2012). P. aeruginosa converts citronellol into citronellic acid by successive enzymatic reactions involving the geraniol dehydrogenase and the citronellal dehydrogenase (Förster-Fromme et al, 2006).…”