posted on 2023-03-28, 16:39authored byNatalia Kakko, Anssi Rantasalo, Tino Koponen, Virve Vidgren, Matti Kannisto, Natalia Maiorova, Heli Nygren, Dominik Mojzita, Merja Penttilä, Paula Jouhten
Engineered microbial cells can produce sustainable chemistry,
but
the production competes for resources with growth. Inducible synthetic
control over the resource use would enable fast accumulation of sufficient
biomass and then divert the resources to production. We developed
inducible synthetic resource-use control overSaccharomyces
cerevisiae by expressing a bacterial ClpXP proteasome
from an inducible promoter. By individually targeting growth-essential
metabolic enzymes Aro1, Hom3, and Acc1 to the ClpXP proteasome, cell
growth could be efficiently repressed during cultivation. The ClpXP
proteasome was specific to the target proteins, and there was no reduction
in the targets when ClpXP was not induced. The inducible growth repression
improved product yields from glucose (cis,cis-muconic acid) and per
biomass (cis,cis-muconic acid and glycolic acid). The inducible ClpXP
proteasome tackles uncertainties in strain optimization by enabling
model-guided repression of competing, growth-essential, and metabolic
enzymes. Most importantly, it allows improving production without
compromising biomass accumulation when uninduced; therefore, it is
expected to mitigate strain stability and low productivity challenges.