title: Production process monitoring by serial mapping of microbial carbon flux distributions using a novel Sensor Reactor approach: II--(13)C-labeling-based metabolic flux analysis and L-lysine production.
abstract: Corynebacterium glutamicum is intensively used for the industrial large-scale (fed-) batch production of amino acids, especially glutamate and lysine. However, metabolic flux analyses based on 13C-labeling experiments of this organism have hitherto been restricted to small-scale batch conditions and carbon-limited chemostat cultures, and are therefore of questionable relevance for industrial fermentations. To lever flux analysis to the industrial level, a novel Sensor Reactor approach was developed (El Massaoudi et al., Metab. Eng., submitted), in which a 300-L production reactor and a 1-L Sensor Reactor are run in parallel master/slave modus, thus enabling 13C-based metabolic flux analysis to generate a series of flux maps that document large-scale fermentation courses in detail. We describe the successful combination of this technology with nuclear magnetic resonance (NMR) analysis, metabolite balancing methods and a mathematical description of 13C-isotope labelings resulting in a powerful tool for quantitative pathway analysis during a batch fermentation. As a first application, 13C-based metabolic flux analysis was performed on exponentially growing, lysine-producing C. glutamicum MH20-22B during three phases of a pilot-scale batch fermentation. By studying the growth, (co-) substrate consumption and (by-) product formation, the similarity of the fermentations in production and Sensor Reactor was verified. Applying a generally applicable mathematical model, which included metabolite and carbon labeling balances for the analysis of proteinogenic amino acid 13C-isotopomer labeling data, the in vivo metabolic flux distribution was investigated during subsequent phases of exponential growth. It was shown for the first time that the in vivo reverse C(4)-decarboxylation flux at the anaplerotic node in C. glutamicum significantly decreased (70%) in parallel with threefold increased lysine formation during the investigated subsequent phases of exponential growth.
authors.affiliation: Institute of Biotechnology, Research Center Jülich, Forschungszentrum Julich GmbH, 52425 Jülich, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Drysch
authors.forename: M
authors.initials: M
authors.lastname: El Massaoudi
authors.forename: C
authors.initials: C
authors.lastname: Mack
authors.forename: R
authors.initials: R
authors.lastname: Takors
authors.forename: A A
authors.initials: AA
authors.lastname: de Graaf
authors.forename: H
authors.initials: H
authors.lastname: Sahm
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002244:Carbon / Q000032:analysis / Q000378:metabolism*; D002247:Carbon Isotopes / Q000378:metabolism; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D003198:Computer Simulation; D003352:Corynebacterium / Q000145:classification / Q000254:growth & development* / Q000378:metabolism*; D003947:Diagnostic Techniques, Radioisotope; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods; D005947:Glucose / Q000378:metabolism; D007553:Isotope Labeling / Q000379:methods; D008239:Lysine / Q000096:biosynthesis*; D008954:Models, Biological; D010865:Pilot Projects
chemical_list: D002247:Carbon Isotopes; D002244:Carbon; D005947:Glucose; D008239:Lysine