초록
<P><B>Abstract</B></P> <P>Balanced utilization of metabolic intermediates and controllable expression of genes in biosynthetic pathways are key issues for the effective production of value-added chemicals in microbes. An inducer/repressor-free sequential control strategy regulated by glucose concentration in the growth environment was proposed to address these issues, and its efficiency was validated using heterologous beta-carotenoid biosynthesis in <I>Saccharomyces cerevisiae</I> as an example. Through sequential control of the downstream, upstream, and competitive pathways of farnesyl diphosphate (FPP), the crucial metabolic node in the biosynthesis of terpenoids, in a predetermined order, a carotenoid production of 1156mg/L (20.79mg/g DCW) was achieved by high-cell density fermentation. Quantitative PCR analysis of the regulated genes demonstrated that the transcription patterns were controlled in a sequential manner as expected. The inducer/repressor-free nature of this strategy offers a both practical and economically efficient approach to improved biosynthetic production of value-added chemicals.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Constructed a carotenoid colorimetric-based promoter strength comparison system. </LI> <LI> Proposed an inducer/repressor-free sequential control strategy for balanced utilization of metabolic intermediates. </LI> <LI> Achieved a carotenoid production of 1156mg/L (20.79mg/g DCW) in <I>S. cerevisiae</I> by high-cell density fermentation. </LI> </UL> </P>