Impact of oxygen availability on organelle-specific redox potentials and stress in recombinant protein producing Pichia pastoris

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Going beyond the limit: impact of increasing global translation activity on the productivity of recombinant secreted proteins in Pichia pastoris

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Flo8 – A versatile regulator for improving recombinant protein production in Pichia pastoris

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Slow growth rate triggered transition to a pseudohyphal lifestyle of the protein production host Pichia pastoris

Specific growth rate is an important process control parameter for industrial protein production. In the widely used yeast protein production host Pichia pastoris, growth rate is known to significantly impact protein expression and secretion [1]. In that regard, glucose-limited chemostat cultivations carried out over a wide range of specific growth rates have revealed that slow growth rates can trigger a pseudohyphal phenotype in P. pastoris [2]. Such phenotypes are undesirable during large-scale protein production processes since they can lead to foam production. In Saccharomyces cerevisiae pseudohyphal growth is controlled by FLO11, a member of the FLO gene family, which is a group of genes encoding cell surface proteins responsible for conferring a diverse array of adhesion-related phenotypes and reported to be controlled by epigenetic mechanisms. P. pastoris also carries a number of FLO genes but their functions and regulatory patterns are yet unknown. Thus, we set out to investigate this gene family to shed some light on how pseudohyphal growth and other adhesion phenotypes are triggered and regulated in P. pastoris. Please click Additional Files below to see the full abstract

Recent advances in Pichia pastoris as host for heterologous expression system for lipases : a review

The production of heterologous lipases is one of the most promising strategies to increase the productivity of the bioprocesses and to reduce costs, with the final objective that more industrial lipase applications could be implemented. In this chapter, an overview of the new success in synthetic biology, with traditional molecular genetic techniques and bioprocess engineering in the last 5 years in the cell factory Pichia pastoris, the most promising host system for heterologous lipase production, is presented. The goals get on heterologous Candida antarctica, Rhizopus oryzae, and Candida rugosa lipases, three of the most common lipases used in biocatalysis, are showed. Finally, new cell factories producing heterologous lipases are presented

Detection and elimination of cellular bottlenecks in protein-producing yeasts

Yeasts are efficient cell factories and are commonly used for the production of recombinant proteins for biopharmaceutical and industrial purposes. For such products high levels of correctly folded proteins are needed, which sometimes requires improvement and engineering of the expression system. The article summarizes major breakthroughs that led to the efficient use of yeasts as production platforms and reviews bottlenecks occurring during protein production. Special focus is given to the metabolic impact of protein production. Furthermore, strategies that were shown to enhance secretion of recombinant proteins in different yeast species are presented

Physiological state as transferable operating criterion to improve recombinant protein production in Pichia pastoris through oxygen limitation

BACKGROUND: The yeast Pichia pastoris is widely used as a production platform for secreted recombinant protein. The application of oxygen-limiting conditions leads to an important increase in protein specific productivity driven by the GAP promoter. RESULTS: The physiological and metabolic adaptation of the host to a wide range of oxygen availability has been systematically studied in glucose-limited chemostat cultivations producing an antibody fragment (Fab). A weighty increase of up to 3-fold of the specific Fab production rate (qFab) and Fab yield (YPX) has been achieved for the optimal conditions. Besides the remarkable increase on both Fab yield and productivity, as a consequence of the metabolic shift from respiratory to respiro-fermentative pathways, a decrease on biomass yield and generation of several secreted by-products have been observed. CONCLUSION: The accurate system characterization achieved throughout the bioprocess specific rates and the monitoring of cell physiology allowed the determination of the optimal conditions to enhance bioprocess efficiency. This work also presents a versatile approach based on the physiological state of the yeast that can be used to implement the desired oxygen-limiting conditions to fermentations set-ups with different oxygen transfer capacities, alternative operating modes, and even for the production of other proteins of interest