Skip to main content
Fig. 6 | Biotechnology for Biofuels

Fig. 6

From: Combining directed evolution of pathway enzymes and dynamic pathway regulation using a quorum-sensing circuit to improve the production of 4-hydroxyphenylacetic acid in Escherichia coli

Fig. 6

a The quorum-sensing (QS) system for 4HPAA production. In the absence of 3-oxohexanoyl-homoserine lactone (AHL, red triangle), the transcriptional regulator EsaRI70V binds the PesaR promoter and represses the transcription of the pathway enzymes. EsaI proteins synthesizes autoinducer AHL, which can diffuse in or out cells and binds to the transcriptional regulator EsaRI70V. At the threshold level of AHL, which accumulates in proportion to cell density, the transcriptional regulator EsaRI70V binds to AHL, leading to dissociation of EsaRI70Vfrom the PesaR promoter, and the EsaRI70V-AHL complex activates the transcription of the pathway enzymes. b Fed-batch cultures of E. coli DOPA-30N harboring the QS-controlled (squares) and the statically controlled (circles) pathway for 4HPAA production. Growth (open: open square, open circle); 4HPAA concentration (black: filled square, filled circle). Experiments were conducted in duplicate, and measurements are presented as the means with standard deviations

Back to article page