title: Cultivation strategies to enhance productivity of Pichia pastoris: A review.
abstract: Pichia pastoris, a methylotrophic yeast, is an established system for the production of heterologous proteins, particularly biopharmaceuticals and industrial enzymes. To maximise and optimise the production of recombinant products, recent molecular research has focused on numerous issues including the design of expression vectors, optimisation of gene copy number, co-expression of secretory proteins such as chaperones, engineering of glycosylation and secretory pathways, etc. However, the physiological effects of different cultivation strategies are often difficult to separate from the molecular effects of the gene construct (e.g., cellular stress through over-expression or incorrect post-translational processing). Hence, overall system optimisation is difficult, even though it is urgently required in order to describe and understand the behaviour of new molecular constructs. This review focuses on particular aspects of recombinant protein production related to variations in biomass growth and their implications for strain design and screening, as well as on the concept of rational comparisons between cultivation systems for the development of specific production processes in bioreactors. The relationship between specific formation rates of secreted recombinant proteins, qp, and specific growth rates, μ, has been analysed in a conceptual attempt to compare different systems, particularly those based on AOX1/methanol and GAP/glucose, and this has now evolved into a pivotal concept for bioprocess engineering of P. pastoris.
authors.affiliation: Institute of Biotechnology, Zurich University of Applied Sciences (ZHAW), Campus Grüental, CH-8820 Wädenswil, Switzerland.
authors.forename: V
authors.initials: V
authors.lastname: Looser
authors.affiliation: Institute of Biotechnology, Zurich University of Applied Sciences (ZHAW), Campus Grüental, CH-8820 Wädenswil, Switzerland.
authors.forename: B
authors.initials: B
authors.lastname: Bruhlmann
authors.affiliation: Institute of Biotechnology, Zurich University of Applied Sciences (ZHAW), Campus Grüental, CH-8820 Wädenswil, Switzerland.
authors.forename: F
authors.initials: F
authors.lastname: Bumbak
authors.affiliation: Institute of Biotechnology, Zurich University of Applied Sciences (ZHAW), Campus Grüental, CH-8820 Wädenswil, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Stenger
authors.affiliation: Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Costa
authors.affiliation: Bioprocessing Technology Institute, Agency for Science, Technology and Research, 20 Biopolis Way, #06-01 Centros, SGP-138668 Singapore, Singapore.
authors.forename: A
authors.initials: A
authors.lastname: Camattari
authors.affiliation: Institute of Biochemistry and Molecular Medicine, University of Bern, Bühlstrasse 28, CH-3012 Bern, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Fotiadis
authors.affiliation: Institute of Biotechnology, Zurich University of Applied Sciences (ZHAW), Campus Grüental, CH-8820 Wädenswil, Switzerland. Electronic address: koka@zhaw.ch.
authors.forename: K
authors.initials: K
authors.lastname: Kovar
mesh_terms: D018533:Biomass; D001709:Biotechnology; D018929:Cell Culture Techniques / Q000379:methods*; D007700:Kinetics; D010843:Pichia / Q000254:growth & development*; D011994:Recombinant Proteins / Q000096:biosynthesis
chemical_list: D011994:Recombinant Proteins
keywords: Fermentation; Pichia pastoris; Production process development; Productivity; Recombinant protein