Fermentation of strain harboring CRISPRi system to repress by-product pathways. (A) Biomass (OD600) of the CRISPRi strain in the shake flask. (B) Glucose consumption of CRISPRi strain in the shake flask. (C) Glycerol production by CRISPRi strain in the shake flask. (D) 3-Hydroxypropionic acid production by CRISPRi strain in the shake flask. (E) Lactic acid production by CRISPRi strain in the shake flask. (F) Acetic acid production by CRISPRi strain in the shake flask. (G) 1,3-Propanediol production of CRISPRi strain in the shake flask. (H) 2,3-Butanediol production by CRISPRi strain in the shake flask. (I) Metabolites of CRISPRi strain KP-GB2 in the shake flask. (J) Metabolites of CRISPRi strain KP-GB2 in fed-batch culture. KP-dCas9, the recombinant K. pneumoniae strain with dCas9 integrated in genome; KP-15A, the recombinant K. pneumoniae strain harboring empty vector ptac-15A; KP-GS, the recombinant K. pneumoniae with dCas9 integrated in genome, and harboring vector ptac-GS co-expressing non-target sgRNA, gpd1 and gpp2; KP-GG1, recombinant K. pneumoniae with dCas9 integrated in genome of and ptac-GG1 plasmid co-expressing gpd1, gpp2, and gapA-targeting sgRNA; KP-GB2, the recombinant K. pneumoniae with dCas9 integrated in genome and vector ptac-GB2 co-expressing gpd1, gpp2, and budA-targeting sgRNA; KP-GGB, the recombinant K. pneumoniae with dCas9 integrated in genome and plasmid ptac-GGB co-expressing gpd1, gpp2, and sgRNAs targeting gapA and budA. 3-HP, 3-hydroxypropionic acid; LA, lactic acid; AA, acetic acid; 1,3-PDO, 1,3-propanediol; and 2,3-BDO, 2,3-butanediol.