Fig. 3

Effect of single gene inhibition on surfactin production in B. subtilis. a The surfactin production resulting from CRISPRi-based single gene interference in the BS168NU-Sd strain with the addition of 4 g/L xylose as an inducer. b The OD₆₀₀ of single gene interference in the BS168NU-Sd strain with the addition of 4 g/L xylose inducer in the medium. c Changes in OD₆₀₀ in the BS168NU-Sd, yrpC, racE and murC strains. d Changes in surfactin production in the BS168NU-Sd, yrpC, racE and murC strains. The surfactin production and cell growth of the recombinant strains were all determined 24 h after inoculation in 5 mL of semi-defined fermentation medium. The different colours represent the different types of strains: light grey: wild type; green: control; light cameo brown: the strains with l-aspartate metabolic modules; light yellow: the strains with l-valine and l-leucine metabolic modules; light green: the strains with l-glutamate metabolic modules