Glucose-methanol co-utilization in Pichia pastoris studied by metabolomics and instationary 13C flux analysis
Jorda J, Suarez C, Carnicer M, Ten Pierick A, Heijnen JJ, Van Gulik W, Ferrer P, Albiol J, Wahl SA (2013)
Publication Type: Journal article
Publication year: 2013
Journal
Book Volume: 7
Article Number: 17
Abstract
Background: Several studies have shown that the utilization of mixed carbon feeds instead of methanol as sole carbon source is beneficial for protein production with the methylotrophic yeast Pichia pastoris. In particular, growth under mixed feed conditions appears to alleviate the metabolic burden related to stress responses triggered by protein overproduction and secretion. Yet, detailed analysis of the metabolome and fluxome under mixed carbon source metabolizing conditions are missing. To obtain a detailed flux distribution of central carbon metabolism, including the pentose phosphate pathway under methanol-glucose conditions, we have applied metabolomics and instationary 13C flux analysis in chemostat cultivations.Results: Instationary 13C-based metabolic flux analysis using GC-MS and LC-MS measurements in time allowed for an accurate mapping of metabolic fluxes of glycolysis, pentose phosphate and methanol assimilation pathways. Compared to previous results from NMR-derived stationary state labelling data (proteinogenic amino acids, METAFoR) more fluxes could be determined with higher accuracy. Furthermore, using a thermodynamic metabolic network analysis the metabolite measurements and metabolic flux directions were validated. Notably, the concentration of several metabolites of the upper glycolysis and pentose phosphate pathway increased under glucose-methanol feeding compared to the reference glucose conditions, indicating a shift in the thermodynamic driving forces. Conversely, the extracellular concentrations of all measured metabolites were lower compared with the corresponding exometabolome of glucose-grown P. pastoris cells.The instationary 13C flux analysis resulted in fluxes comparable to previously obtained from NMR datasets of proteinogenic amino acids, but allowed several additional insights. Specifically, i) in vivo metabolic flux estimations were expanded to a larger metabolic network e.g. by including trehalose recycling, which accounted for about 1.5% of the glucose uptake rate; ii) the reversibility of glycolytic/gluconeogenesis, TCA cycle and pentose phosphate pathways reactions was estimated, revealing a significant gluconeogenic flux from the dihydroxyacetone phosphate/glyceraldehydes phosphate pool to glucose-6P. The origin of this finding could be carbon recycling from the methanol assimilatory pathway to the pentose phosphate pool. Additionally, high exchange fluxes of oxaloacetate with aspartate as well as malate indicated amino acid pool buffering and the activity of the malate/Asp shuttle; iii) the ratio of methanol oxidation vs utilization appeared to be lower (54 vs 79% assimilated methanol directly oxidized to CO
Authors with CRIS profile
Involved external institutions
Delft University of Technology (TU Delft)
Netherlands (NL)
Autonomous University of Barcelona (UAB) / Universitat Autònoma de Barcelona
Spain (ES)
Netherlands (NL)
Autonomous University of Barcelona (UAB) / Universitat Autònoma de Barcelona
Spain (ES)
How to cite
APA:
Jorda, J., Suarez, C., Carnicer, M., Ten Pierick, A., Heijnen, J.J., Van Gulik, W.,... Wahl, S.A. (2013). Glucose-methanol co-utilization in Pichia pastoris studied by metabolomics and instationary 13C flux analysis. BMC Systems Biology, 7. https://dx.doi.org/10.1186/1752-0509-7-17
MLA:
Jorda, Joel, et al. "Glucose-methanol co-utilization in Pichia pastoris studied by metabolomics and instationary 13C flux analysis." BMC Systems Biology 7 (2013).
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