title: Lower temperature cultures enlarge the effects of Vitreoscilla hemoglobin expression on recombinant Pichia pastoris.
abstract: An heterologous expression of Vitreoscilla hemoglobin (VHb) for improving cell growth and recombinant protein production has been successfully demonstrated in various hosts, including Pichia pastoris. Lower temperature cultures can enhance target protein production in some studies of P. pastoris. In this study, the strategy of combining heterologous VHb expression and lower temperature cultures in P. pastoris showed that final cell density and viability of VHb+ strain at 23 &deg;C were higher than that at 30 &deg;C. In addition, the effects of VHb expression on recombinant &beta;-galactosidase production  and oxygen uptake rate were also higher at 23 &deg;C than at 30 &deg;C. Consequently, lower temperature cultures can enlarge VHb effectiveness on cell performance of P. pastoris. This is because VHb activity obtained at 23 &deg;C cultures was twofold higher than that at  30 &deg;C cultures, due to a different heme production. This strategy makes P. pastoris an excellent expression host particularly suitable for increasing the yields of the low-stability and aggregation-prone recombinant proteins.
authors.affiliation: Department of Chemical and Materials Engineering, Chinese Culture University, 55, Hwa-Kang Rd., Yang-Ming-Shan, Taipei 111-14, Taiwan. wzm4@faculty.pccu.edu.tw.
authors.forename: Jyh-Ming
authors.initials: JM
authors.lastname: Wu
authors.forename: Shin-Yao
authors.initials: SY
authors.lastname: Wang
authors.forename: Wei-Chang
authors.initials: WC
authors.lastname: Fu
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018533:Biomass; D049109:Cell Proliferation / Q000187:drug effects; D006427:Hemin / Q000494:pharmacology; D010100:Oxygen / Q000378:metabolism; D010843:Pichia; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D013696:Temperature; D054793:Truncated Hemoglobins / Q000235:genetics / Q000378:metabolism*; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D054793:Truncated Hemoglobins; C082613:hemoglobin protein, Vitreoscilla; D006427:Hemin; D001616:beta-Galactosidase; D010100:Oxygen