Fig. 6

Multiple gene modifications for 1,2-propanediol production in C. glutamicum using the RecET-assisted CRISPR–Cas9 method. a Strategy of the multiple gene modifications for 1,2-propanediol production in C. glutamicum. b The impact of Pgk flux on cellular metabolism was investigated with decreasing relative Pgk fluxes (between 1.0 and 0.1). X-axis: relative Pgk flux (the ratio of the test Pgk flux to the native Pgk flux). Relative Pgk flux = 1.0 served as the control (or native GPD flux). Y-axis: relative flux of the pathways (the ratio of the test flux to the native flux). Yellow represents no change, red represents upregulation, and blue represents downregulation of the flux. c Flask cultivation of C. glutamicum strains for 1,2-propanediol (1,2-PDO) production. PTΔΔ: PT ΔldhΔhdpA; PTΔΔP _hom : PTΔldh ΔhdpAP _hom -pgk; PTΔΔP _dapA : PTΔldhΔhdpAP _dapA -pgk. The data are derived from experiments performed at least three times, and the error bars represent the standard deviations. d Relative transcript levels of related genes in the different C. glutamicum strains at the exponential growth phase. Red column: PT ΔldhΔhdpA; blue column: PTΔldh ΔhdpAP _hom -pgk; green column: PTΔldhΔhdpAP _dapA -pgk