Customized optimization of metabolic pathways by combinatorial transcriptional engineering.

Introduction of a heterologous metabolic pathway into a platform microorganism for applications in metabolic engineering and synthetic biology is often technically straightforward. However, the major challenge is to balance the flux in the pathway to obtain high yield and productivity in a target microorganism. To address this limitation, we recently developed a simple, efficient, and programmable approach named "customized optimization of metabolic pathways by combinatorial transcriptional engineering" (COMPACTER) for balancing the flux in a pathway under distinct metabolic backgrounds. Here we use two examples including a cellobiose-utilizing pathway and a xylose-utilizing pathway to illustrate the key steps in the COMPACTER method.