Medium chain length polyhydroxyalkanoates biosynthesis in Pseudomonas putida mt-2 is enhanced by co-metabolism of glycerol/octanoate or fatty acids mixtures.
The synthesis of medium chain length polyhydroxyalkanoates (mcl-PHAs) by Pseudomonas putida mt-2 was investigated under nitrogen-rich then deficient conditions with glycerol/octanoate or long-chain fatty acids (LCFAs) as carbon sources. When mixed, glycerol and octanoate were co-assimilated regardless of nitrogen availability but provided that glycerol uptake has been already triggered under non-limiting nutrient conditions. This concomitant consumption allowed to enhance mcl-PHAs accumulation (up to 57% of cell dry weight (CDW)) under both non-limiting and nitrogen deficient conditions. Octanoate then mostly drove anabolism of the polyester with 3-hydroxyoctanoate (3HO) synthesized as the main monomer (83%). If the preferred PHA precursor octanoate was supplied, glycerol was mainly involved in cell growth and/or maintenance but very little in PHA production even under nitrogen starvation. P. putida cells accumulated higher amounts of mcl-PHAs when grown on mixtures of LCFAs compared to LCFAs supplied as single substrate (25% and 9% of CDW, respectively). However, only a weak enrichment of the polyester was observed after transfer of cells in a fresh nitrogen-free medium containing the same combination of LCFAs. Some typical units within the polyester were related to the LCFAs ratio supplied in the medium indicating that tailor-made monomers could be synthesized.
Normandie Univ., UNICAEN, UR ABTE, 14000 Caen, France.
Paul
P
Fontaine
Normandie Univ., UNICAEN, UR ABTE, 14000 Caen, France.
Ridha
R
Mosrati
Normandie Univ., UNICAEN, UR ABTE, 14000 Caen, France. Electronic address: david.corroler@unicaen.fr.
David
D
Corroler
D002210:Caprylates / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism*; D006868:Hydrolysis; D009584:Nitrogen / Q000494:pharmacology; D054813:Polyhydroxyalkanoates / Q000096:biosynthesis* / Q000737:chemistry*; D016958:Pseudomonas putida / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*
D002210:Caprylates; D054813:Polyhydroxyalkanoates; D009584:Nitrogen; C031492:octanoic acid; D005990:Glycerol
Co-metabolism; Glycerol; Octanoate; Polyhydroxyalkanoates; Pseudomonas putida