Zhang, C., & Shukal, S. (2025). Arabinose-Inducible Univariant Control System (AUCS) for Microbial Production of Proteins, Enzymes, and Metabolites. ACS Synthetic Biology, 15(1), 171–180. https://doi.org/10.1021/acssynbio.5c00602
Abstract:
Precise control of gene expression is essential to synthetic biology and metabolic engineering, particularly for microbial production. The widely used IPTG-inducible T7lac promoter (PT7lac) offers strong expression but suffers from metabolic burden, inclusion body formation, and induction heterogeneity. Conversely, the arabinose-inducible araBAD promoter (PBAD) provides tight regulations but yields modest expression levels, is incompatible with glucose media, and requires high inducer concentrations (20-100 mM). We introduce the arabinose-inducible univariant control system (AUCS), a robust, tightly regulated, and low-cost expression platform designed to combine the strengths of PT7lac and PBAD while overcoming their drawbacks. AUCS eliminates carbon catabolite repression and minimizes induction heterogeneity via the constitutive expression of the arabinose transporter AraE. Disruption of the arabinose catabolism enables maximal protein output with only 3 μM l-arabinose, orders of magnitude lower than PT7lac and PBAD systems, achieving a >99% reduction in inducer cost. Leveraging a customized promoter library (PTA1-3), AUCS enables the precise, high-yield expression of single proteins, multienzyme operons, and complex biosynthetic pathways (>10 genes). Benchmarked against PT7lac, AUCS achieved comparable or superior yields of proteins (the egg-white protein ovalbumin), enzymes (terpene synthases, carotenoid cleavage dioxygenases), and secondary metabolites (linalool, nerolidol, and sclareol) while maintaining outstanding reproducibility and stability over 36 generations. AUCS represents a powerful advancement for precision fermentation, enabling sustainable and cost-effective production of high-value biomolecules and substantially reducing the environmental footprint of chemical manufacturing.
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Funding Info:
This research / project is supported by the Biomedical Research Council - Central Research Fund
Grant Reference no. : SIF-GF25-0370, 2024
This research / project is supported by the Agency for Science, Technology and Research (A*STAR), Singapore - Singapore Food Story R&D Programme
Grant Reference no. : H20H8A0001