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. 2022 Mar 9;119(11):e2119980119. doi: 10.1073/pnas.2119980119

Fig. 5.

Fig. 5.

Combinatorial optimization of the riboflavin and violacein biosynthesis pathways employing the MATE system in B. subtilis. (A) Schematic of the strategy to optimize the biosynthesis pathway of riboflavin with the MATE-ON and MATE-OFF regulatory system in B. subtilis. (B) Genetic manipulation of the rib operon and ribC gene with elements from the MATE-ON and MATE-OFF system in B. subtilis. (C) Riboflavin production by the engineered and control strains during 72 h of shake flask cultivation. (D) Cultures of riboflavin-producing strains after 72 h. The strain harboring an empty plasmid pMATE15 served as a negative control (NC). The plus and minus characters in parentheses indicate cultivation with and without 1% (wt/vol) maltose as inducer, respectively. (E) Schematic of the strategy to optimize the biosynthesis pathway of L-tryptophan with the MATE-ON and MATE-OFF regulatory system in B. subtilis. (F) Design of the artificial violacein biosynthesis operon (pVio), inducible activated trp operon (TrpOp), and inducible repressive aroH gene (Chor) using elements from the MATE system in B. subtilis. (G) Violacein production by three engineered strains, pVio, TrpOp-pVio, and Chor-pVio, after 48 h of shake flask cultivation. (H) Cultures of violacein-producing strains after 48 h. The strain harboring an empty plasmid pMATE15 served as a negative control.