Fig. 2

Utilization of three generations of biorefinery materials based on the surface display system of C. glutamicum, including surface display, transporters, and metabolic reactions. Overview of the surface display, transporters, and metabolic reactions in C. glutamicum for uptake and conversion of three generations of biorefinery materials. Black represents the endogenous reaction of C. glutamicum, and * represents foreign proteins expressed by heterologous genes. Purple indicates the utilization path of the first-generation of biorefinery, blue indicates the utilization path of the second-generation of biorefinery, and orange indicates the possible utilization path of the third-generation of biorefinery. The solid line represents direct reactions, and the dashed line represents indirect reactions. Enzymes of the Cre pathway: CreHI, CreJEF, CreG, CreC, and CreD; enzymes of the Paa pathway: PaaK, PaaABCDE, PaaG, PaaZ, PaaG/J, PaaF, PaaH, and PaaJ; amino acid transporter: LyaE for L-lysine, L-arginine, L-citrulline; CgmA for L-arginine; YggB: L-glutamate; ThrE for L-threonine, L-serine; BrnEF: L-valine, L-leucine, L-isoleucine, L-methionine. Glc glucose, Glc6P glucose-6-phosphate, Fru6P frucose-6-phosphate, Xyl xylose, Ara, arabinose, CelE endoglucanase E, BglA β-glucosidase A, Msc mechanosensitive channel, Glc1P, glucose-1-phosphate, F6P fructose-6-phosphate, PYR pyruvate, Gluc6P,gluconate-6-phosphate, Glc6P gluconate-1-phosphate, Man, mannose, Man6P mannose-6-phosphate, Ara arabinose, AraA arabinose isomerase, AraB ribulokinase, AraD ribulose 5-phosphate 4-epimerase, Ru ribulose, L-Ru5P L-ribulose-5-phosphate, D-Ru5P D-ribulose-5-phosphate, PEP phosphoenolpyruvate, DHAP 1,3-dihydroxyacetone phosphate, and PCA protocatechuate. PTS phosphoenolpyruvate phosphotransferase, Xylu5P xylulose-5-phosphate, D-Ribo5P ribose-5-phosphate, Xyl xylose, XylA xylose isomerase, XylB xylulokinase, Xu xylulose, PP pathway, pentose phosphate pathway, TCA tricarboxylic acid cycle, Vdh putative vanillin dehydrogenase gene, vanAB genes encoding subunits A and B of vanillate demethylase, PAA phenylacetic acid, Fcs feruloyl-CoA synthetase, Ech enoyl-CoA hydratase/aldolase, PobA 4-hydroxybenzoate 3-hydroxylase (NCgl1032), CatA catechol 1,2-dioxygenase (NCgl2319), BenABC benzoate dioxygenase complex, encoded putatively by NCgl2320, NCgl2321, and NCgl2322, benD 2-hydro-1,2dihydroxybenzoate dehydrogenase (putatively encoded by NCgl2323), MucK a native MFS transporter known to import muconate in ADP1 (from Acinetobacter baylyi), DCD 1,2-dihydroxy-3,5-cyclo-hexadiene-1,4-dicarboxylate