Figure 1. Schematic representation of the L-arginine biosynthesis pathway of C. crenatum and of the metabolic engineering steps performed in this study.

Gray boxes represent the targeted modifications of the genes and all modifications were implemented into the genome. Green arrows indicate amplification, red arrows indicate attenuation or deletion, and the symbol “×” indicates gene deletion. Genes and enzymes: argB, N-acetylglutamate kinase; pfk, phosphofructokinase; pgi, phosphoglucoisomerase; ptsG, glucose-specific EIIABC^Glc component; iolT1, inositol permease; ppgk, glucose kinase; pyc, pyruvate carboxylase; gltA, citrate synthase; icd, isocitrate dehydrogenase; gdh, glutamate dehydrogenase; odhA, α-ketoglutarate dehydrogenase; lysC, aspartokinase; proB, glutamate kinase.