Premium
Two different pathways are involved in the β‐oxidation of n ‐alkanoic and n ‐phenylalkanoic acids in Pseudomonas putida U: genetic studies and biotechnological applications
Author(s) -
Olivera Elías R.,
Carnicero David,
García Belén,
Miñambres Baltasar,
Moreno Miguel A.,
Cañedo Librada,
DiRusso Concetta C.,
Naharro Germán,
Luengo José M.
Publication year - 2001
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2001.02296.x
Subject(s) - pseudomonas putida , mutant , enzyme , catabolism , biology , biochemistry , moiety , amino acid , metabolic engineering , gene , stereochemistry , chemistry
In Pseudomonas putida U, the degradation of n ‐alkanoic and n ‐phenylalkanoic acids is carried out by two sets of β‐oxidation enzymes (β I and β II ). Whereas the first one (called β I ) is constitutive and catalyses the degradation of n ‐alkanoic and n ‐phenylalkanoic acids very efficiently, the other one (β II ), which is only expressed when some of the genes encoding β I enzymes are mutated, catabolizes n ‐phenylalkanoates ( n > 4) much more slowly. Genetic studies revealed that disruption or deletion of some of the β I genes handicaps the growth of P. putida U in media containing n ‐alkanoic or n ‐phenylalkanoic acids with an acyl moiety longer than C 4 . However, all these mutants regained their ability to grow in media containing n ‐alkanoates as a result of the induction of β II , but they were still unable to catabolize n ‐phenylalkanoates completely, as the β I ‐FadBA enzymes are essential for the β‐oxidation of certain n ‐phenylalkanoyl‐CoA derivatives when they reach a critical size. Owing to the existence of the β II system, mutants lacking β I fad B/A are able to synthesize new poly 3‐OH‐ n ‐alkanoates (PHAs) and poly 3‐OH‐ n ‐phenylalkanoates (PHPhAs) efficiently. However, they are unable to degrade these polymers, becoming bioplastic overproducer mutants. The genetic and biochemical importance of these results is reported and discussed.