title: Dynamic flux balance analysis for pharmaceutical protein production by Pichia pastoris: human growth hormone.
abstract: The influence of methanol feeding rate on intracellular reaction network of recombinant human growth hormone (rhGH) producing Pichia pastoris was investigated at three different specific growth rates, namely, 0.02 (MS-0.02), 0.03 (MS-0.03), and 0.04 h(-1) (MS-0.04) where Period-I (33 ≤ t <42 h) includes the early exponential growth phase; Period-II (42 ≤ t<48 h) is the exponential growth phase where the specific cell growth rate decreases; Period-III (48 ≤ t ≤51 h) is the exponential growth phase where rhGH concentration was the highest; and Period-IV (t>51 h) is the diminution phase for rhGH and cell synthesis. In Period-I, almost all of the formaldehyde entered the assimilatory pathway, at MS-0.02 and MS-0.03, whereas, at MS-0.04 high methanol feeding rate resulted in an adaptation problem. In Period-III, only at MS-0.02 co-carbon source sorbitol uptake-flux was active showing that sorbitol uptake does not affected from the predetermined feeding rate of methanol at μ(0)>0.02 h(-1). The biomass synthesis flux value was the highest in Period-I, -II and -III, respectively at MS-0.03 & MS-0.04, MS-0.04 and MS-0.02; whereas, rhGH flux was the highest in Period-I, -II, and -III, respectively at MS-0.03, MS-0.02 and MS-0.03. Based on the fluxes, Period-I should start with MS-0.03 methanol feeding rate and starting from the middle of Period-II methanol feeding rate should be shifted to MS-0.02.
authors: Department of Chemical Engineering, Industrial Biotechnology and Metabolic Engineering Laboratory, Middle East Technical University, 06531 Ankara, Turkey. pcalik@metu.edu.tr
authors: Pınar
authors: P
authors: Calık
authors: Merve
authors: M
authors: Sahin
authors: Hatice
authors: H
authors: Taşpınar
authors: Elif Ş
authors: EŞ
authors: Soyaslan
authors: Bahar
authors: B
authors: Inankur
mesh_terms: D018533:Biomass; D019149:Bioreactors; D001709:Biotechnology / Q000379:methods; D004345:Drug Industry; D005285:Fermentation; D019382:Human Growth Hormone / Q000096:biosynthesis*; D006801:Humans; D000432:Methanol / Q000378:metabolism*; D010843:Pichia / Q000254:growth & development / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis; D013012:Sorbitol / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D019382:Human Growth Hormone; D013012:Sorbitol; D000432:Methanol