title: Genetic modifications and introduction of heterologous pdc genes in Enterococcus faecalis for its use in production of bioethanol.
abstract: Genetically-modified Enterococcus faecalis has a potential of survival and can be used in ethanolic fermentations. Fermentation profiles of E. faecalis JH2-2 were assessed using glucose and lactose as carbon sources. Deletion of lactate dehydrogenase (ldh) genes increased the ethanol production from 0.25 to 0.82 g/l, which was further increased to 0.96 g/l by the insertion of a pyruvate decarboxylase (pdc) gene (from Sarcina ventriculi or Clostridium acetobutylicum) in place ldh1. When grown on lactose, the pdcSv and pdcCa showed 13.6 and 17.6 U mg(-1) of pdc specific activity, respectively. Highest activity (47 U mg(-1)) and ethanol concentration (2.3 g/l) were obtained with pdcCa using an expression plasmid. Formate and acetate were also produced in high quantities. Transcriptional analysis showed that aldehyde alcohol dehydrogenase gene was upregulated up to 16-fold. Further optimizations are required for higher ethanol production.
authors.affiliation: Unité de Recherche Risques Microbiens (U2RM), Université de Caen Basse-Normandie Esplanade de la Paix, 14032 Caen, France.
authors.forename: N F
authors.initials: NF
authors.lastname: Rana
authors.forename: S
authors.initials: S
authors.lastname: Gente
authors.forename: A
authors.initials: A
authors.lastname: Rincé
authors.forename: Y
authors.initials: Y
authors.lastname: Auffray
authors.forename: J M
authors.initials: JM
authors.lastname: Laplace
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D046969:Clostridium acetobutylicum / Q000201:enzymology / Q000235:genetics; D013293:Enterococcus faecalis / Q000235:genetics* / Q000378:metabolism*; D000431:Ethanol / Q000378:metabolism*; D005285:Fermentation; D005561:Formates / Q000378:metabolism; D015870:Gene Expression; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D005947:Glucose / Q000378:metabolism; D006836:Hydro-Lyases / Q000235:genetics / Q000378:metabolism; D007785:Lactose / Q000378:metabolism; D060847:Metabolic Engineering; D030781:Organisms, Genetically Modified; D011768:Pyruvate Dehydrogenase Complex / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D005561:Formates; D011768:Pyruvate Dehydrogenase Complex; D011994:Recombinant Proteins; C030544:formic acid; D000431:Ethanol; D006836:Hydro-Lyases; C045581:lactate dehydratase; D005947:Glucose; D007785:Lactose; D019342:Acetic Acid