title: High-density Escherichia coli cultures for continuous L(-)-carnitine production.
abstract: The use of a biological procedure for L-carnitine production as an alternative to chemical methods must be accompanied by an efficient and highly productive reaction system. Continuous L-carnitine production from crotonobetaine was studied in a cell-recycle reactor with Escherichia coli O44 K74 as biocatalyst. This bioreactor, running under the optimum medium composition (25 mM fumarate, 5 g/l peptone), was able to reach a high cell density (26 g dry weight/l) and therefore to obtain high productivity values (6.2 g L-carnitine l-1 h-1). This process showed its feasibility for industrial L-carnitine production. In addition, resting cells maintained in continuous operation, with crotonobetaine as the only medium component, kept their biocatalytic capacity for 4 days, but the biotransformation capacity decreased progressively when this particular method of cultivation was used.
authors.affiliation: Department of Biochemistry and Molecular Biology B, Faculty of Chemistry, University of Murcia, Spain.
authors.forename: J M
authors.initials: JM
authors.lastname: Obón
authors.forename: J R
authors.initials: JR
authors.lastname: Maiquez
authors.forename: M
authors.initials: M
authors.lastname: Cánovas
authors.forename: H P
authors.initials: HP
authors.lastname: Kleber
authors.forename: J L
authors.initials: JL
authors.lastname: Iborra
mesh_terms: D000217:Acyltransferases; D000693:Anaerobiosis; D001622:Betaine / Q000031:analogs & derivatives / Q000378:metabolism; D019149:Bioreactors; D002331:Carnitine / Q000096:biosynthesis*; D003470:Culture Media; D004790:Enzyme Induction; D004926:Escherichia coli / Q000201:enzymology* / Q000254:growth & development*; D006836:Hydro-Lyases / Q000378:metabolism; D007218:Industrial Microbiology
chemical_list: D003470:Culture Media; D001622:Betaine; C025237:crotonic acid betaine; D000217:Acyltransferases; C060278:crotonobetainyl-CoA carnitine coenzyme A transferase; D006836:Hydro-Lyases; D002331:Carnitine