Autoinduced AND Gate Controls Metabolic Pathway Dynamically in Response to Microbial Communities and Cell Physiological State.

Quorum sensing (QS) systems have been widely applied in biotechnology and synthetic biology that require coordinated, community-level behaviors. Meanwhile, the cell physiological state is another key parameter that affects metabolic pathway regulation. Here, we designed an autoinduced AND gate that responds to both microbial communities and the cell physiological state. A series of tunable QS systems in response to different cell densities were obtained through random mutagenesis of LuxR and optimization of the luxRI promoter; the corresponding suitable stationary phase sensing system was selected after monitoring the fluorescence process during cell growth. The application of the final synthetic device was demonstrated using the polyhydroxybutyrate (PHB) production system. The AND gate system increased PHB production by 1-2-fold in Escherichia coli. This synthetic logic gate is a tool for developing a general dynamic regulation system in metabolic engineering in response to complex signals, without using a specific sensor.