The impact of respiration and oxidative stress response on recombinant α-amylase production by Saccharomyces cerevisiae

• Recombinant protein production is a multi-billion dollar market.
• Heterologous production by yeast generates oxidative stress regardless the target.
• HAP1 overexpression mitigates oxidative stress while enhancing metabolic capacity.
• Overexpression of HAP1 allows higher volumetric productivity of recombinant proteins.
• Strains overexpressing HAP1 may grow in chemostats operated at higher dilution rates.

Studying protein production is important for fundamental research on cell biology and applied research for biotechnology. Yeast Saccharomyces cerevisiae is an attractive workhorse for production of recombinant proteins as it does not secrete many endogenous proteins and it is therefore easy to purify a secreted product. However, recombinant production at high rates represents a significant metabolic burden for the yeast cells, which results in oxidative stress and ultimately affects the protein production capacity. Here we describe a method to reduce the overall oxidative stress by overexpressing the endogenous HAP1 gene in a S. cerevisiae strain overproducing recombinant α-amylase. We demonstrate how Hap1p can activate a set of oxidative stress response genes and meanwhile contribute to increase the metabolic rate of the yeast strains, therefore mitigating the negative effect of the ROS accumulation associated to protein folding and hence increasing the production capacity during batch fermentations.