VTT Technical Research Centre of Finland Ltd, Espoo 02044 VTT, Finland.
School of Chemical Engineering, Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16300, Espoo FI-00076 AALTO, Finland.
ACS Synth Biol. 2023 Apr 21;12(4):1021-1033. doi: 10.1021/acssynbio.2c00467. Epub 2023 Mar 28.
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 over 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.
工程化微生物细胞可以生产可持续的化学物质，但生产会与生长竞争资源。对资源使用进行诱导型合成控制将使足够的生物量快速积累，然后将资源转移到生产中。我们通过从诱导型启动子表达细菌 ClpXP 蛋白酶体，开发了对资源使用的诱导型合成控制。通过将生长必需的代谢酶 Aro1、Hom3 和 Acc1 分别靶向 ClpXP 蛋白酶体，可以在培养过程中有效地抑制细胞生长。ClpXP 蛋白酶体对靶蛋白具有特异性，并且在未诱导时，靶蛋白不会减少。诱导型生长抑制提高了葡萄糖（顺式，顺式-粘康酸）和每生物质（顺式，顺式-粘康酸和乙醇酸）的产物产量。诱导型 ClpXP 蛋白酶体通过对竞争生长必需和代谢酶进行模型指导抑制，解决了菌株优化中的不确定性。最重要的是，它允许在未诱导时提高生产而不影响生物量积累，因此有望缓解菌株稳定性和低生产力的挑战。
