title: Intracellular co-expression of Vitreoscilla hemoglobin enhances cell performance and β-galactosidase production in Pichia pastoris.
abstract: Pichia pastoris has been used to produce various recombinant proteins under high oxygen demand conditions. To improve the heterologous production of β-galactosidase, the vgb gene encoding Vitreoscilla hemoglobin (VHb) was co-expressed in the P. pastoris cytoplasm under the control of the methanol-inducible promoter. Co-expression of VHb under different aeration conditions improved cell performance in terms of growth, viability, respiratory rate, and β-galactosidase production. Under limiting aeration conditions, the VHb(+) strain produced 28.2% more biomass but 31.2% less total β-galactosidase activity than the VHb(-) strain. Under non-limiting aeration conditions, the VHb(+) strain showed 20.3% higher cell growth and 9.9% more total β-galactosidase activity than the VHb(-) strain. Moreover, under these conditions, the VHb(+) strain was 7.7% more viable and had a 28.2% higher oxygen uptake rate (OUR) than the VHb(-) strain. Evidently, VHb can enhance the OUR and promote methanol metabolism, thereby improving cell performance and β-galactosidase production.
authors.affiliation: Department of Chemical and Materials Engineering, Chinese Culture University, 55 Hwa-Kang Road, Yang-Ming-Shan, Taipei 11114, Taiwan. wzm4@faculty.pccu.edu.tw
authors.forename: Jyh-Ming
authors.initials: JM
authors.lastname: Wu
authors.forename: Wei-Chang
authors.initials: WC
authors.lastname: Fu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D003593:Cytoplasm / Q000201:enzymology; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D010100:Oxygen / Q000378:metabolism; D010843:Pichia / Q000201:enzymology* / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D054793:Truncated Hemoglobins / Q000235:genetics*; D020589:Vitreoscilla / Q000235:genetics; D001616:beta-Galactosidase / Q000096:biosynthesis*
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D054793:Truncated Hemoglobins; C082613:hemoglobin protein, Vitreoscilla; D001616:beta-Galactosidase; D010100:Oxygen