title: Metabolic engineering of Pseudomonas fluorescens for the production of vanillin from ferulic acid.
abstract: Vanillin is one of the most important flavors in the food industry and there is great interest in its production through biotechnological processes starting from natural substrates such as ferulic acid. Among bacteria, recombinant Escherichia coli strains are the most efficient vanillin producers, whereas Pseudomonas spp. strains, although possessing a broader metabolic versatility, rapidly metabolize various phenolic compounds including vanillin. In order to develop a robust Pseudomonas strain that can produce vanillin in high yields and at high productivity, the vanillin dehydrogenase (vdh)-encoding gene of Pseudomonas fluorescens BF13 strain was inactivated via targeted mutagenesis. The results demonstrated that engineered derivatives of strain BF13 accumulate vanillin if inactivation of vdh is associated with concurrent expression of structural genes for feruloyl-CoA synthetase (fcs) and hydratase/aldolase (ech) from a low-copy plasmid. The conversion of ferulic acid to vanillin was enhanced by optimization of growth conditions, growth phase and parameters of the bioconversion process. The developed strain produced up to 8.41 mM vanillin, which is the highest final titer of vanillin produced by a Pseudomonas strain to date and opens new perspectives in the use of bacterial biocatalysts for biotechnological production of vanillin from agro-industrial wastes which contain ferulic acid.
authors.affiliation: Department of Agroenvironmental Sciences and Technologies, University of Bologna, Viale Fanin 42, Bologna, Italy.
authors.forename: Diana
authors.initials: D
authors.lastname: Di Gioia
authors.forename: Francesca
authors.initials: F
authors.lastname: Luziatelli
authors.forename: Andrea
authors.initials: A
authors.lastname: Negroni
authors.forename: Anna Grazia
authors.initials: AG
authors.lastname: Ficca
authors.forename: Fabio
authors.initials: F
authors.lastname: Fava
authors.forename: Maurizio
authors.initials: M
authors.lastname: Ruzzi
mesh_terms: D001426:Bacterial Proteins; D001547:Benzaldehydes / Q000378:metabolism*; D018533:Biomass; D003001:Cloning, Molecular; D003373:Coumaric Acids / Q000378:metabolism*; D005285:Fermentation; D006863:Hydrogen-Ion Concentration; D060847:Metabolic Engineering / Q000379:methods*; D016296:Mutagenesis; D011551:Pseudomonas fluorescens / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D001547:Benzaldehydes; D003373:Coumaric Acids; C004999:ferulic acid; C100058:vanillin