title: Comparative reaction engineering studies for succinic acid production from sucrose by metabolically engineered Escherichia coli in fed-batch-operated stirred tank bioreactors.
abstract: This study presents a comparative reaction engineering analysis of metabolically engineered sucrose-utilizing Escherichia coli derived from E. coli K12 MG1655 for the anaerobic production of succinic acid. Production capacities of 16 different recombinant strains were evaluated in 48 parallel fed-batch-operated milliliter-scale stirred tank bioreactors (10 mL) with continuous CO₂ sparging. The effects of recombinant sucrose-utilization systems (csc-operon or scr-operon), enhancements of anaplerotic reactions (pck, ppc, maeA, maeB or heterologous pyc) and gene deletions (ldhA, adhE, ack-pta and ptsG) were studied with respect to the overall process performances of the respective recombinant strains. Both sucrose-utilization systems enabled the production of succinic acid from sucrose in E. coli K12 MG1655. Maximum succinate production was observed by overexpressing the pyruvate carboxylase from Corynebacterium glutamicum resulting in a succinate concentration of 26.8 g L⁻¹ after 48 h and a cell-specific productivity of 0.14 g g⁻¹ h⁻¹. Further experiments in a fed-batch-operated laboratory-scale stirred tank bioreactor (2 L) showed that micro-aerobic conditions preceding the anaerobic phase enhance succinic acid production of E. coli K12 MG1655-derived strains. The work demonstrates the importance of parallel approaches within the scope of applied metabolic engineering studies.
authors.affiliation: Lehrstuhl für Bioverfahrenstechnik, Technische Universität München, Garching, Germany.
authors.forename: Torben
authors.initials: T
authors.lastname: Hoefel
authors.forename: Georg
authors.initials: G
authors.lastname: Faust
authors.forename: Liv
authors.initials: L
authors.lastname: Reinecke
authors.forename: Nicolas
authors.initials: N
authors.lastname: Rudinger
authors.forename: Dirk
authors.initials: D
authors.lastname: Weuster-Botz
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D001709:Biotechnology / Q000379:methods*; D003470:Culture Media; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D060847:Metabolic Engineering; D053858:Metabolic Networks and Pathways; D019802:Succinic Acid / Q000032:analysis / Q000378:metabolism*; D013395:Sucrose / Q000378:metabolism*
chemical_list: D003470:Culture Media; D013395:Sucrose; D019802:Succinic Acid