Fig. 1: Design and development of SIMTeGES.

a Temperature-dependent splicing intein variants are inserted into the GAL4 DNA Binding Domain. At the non-permissive temperature (30 °C), intein remains unspliced, preventing GAL4-tsINT from binding to a specific DNA region and activating downstream GAL promoter expression, thereby directing available resources for cell growth. Upon reaching a specific biomass, transitioning to the permissive temperature (25 °C) induces intein self-splicing, resulting in the generation of functional GAL4 to initiate downstream gene expression and the transition from cell growth to product synthesis. b The colored metabolite lycopene serves as a reporter system, reflecting GAL4 activity for characterizing appropriate intein variants. c mCherry is employed as a reporter gene, utilizing flow cytometry to further investigate the activity and leaky expression of SIMTeGES. d SIMTeGES-GAL4 is employed under diverse carbon source conditions for stable production of sanguinarine. SED, SEDG, SEG, SEGly, and SEGlyG denote different fermentation conditions in SE medium, with the following carbon sources: 20 g L⁻¹ glucose, a combination of 20 g L⁻¹ glucose and 10 g L⁻¹ galactose, 20 g L⁻¹ galactose, 20 g L⁻¹ glycerol, and a combination of 10 g L⁻¹ glycerol and 20 g L⁻¹ galactose, respectively. Significance was calculated using two-way ANOVA followed by Tukey’s multiple comparisons test. Data are presented as mean ± s.d. (n  =  3 biologically independent samples). Source data are provided as a Source Data file.