Fig. 3From: Enhancement of photosynthetic isobutanol production in engineered cells of Synechocystis PCC 6803Schematic overview of the isobutanol synthesis pathway, the genetic constructs for identifying respective bottleneck, and the results from the engineered Synechocystis PCC 6803 strains containing different constructs. a Isobutanol synthesis pathway. The heterogenous enzymes are colored in brown: acetolactate synthase (AlsS) from Bacillus subtilis (B. subtilis), acetohydroxy acid isomeroreductase (IlvC), dihydroxy acid dehydratase (IlvD) from E. coli, and α-ketoisovalerate decarboxylase (Kivd) from L. lactis. The endogenous genes are colored in green. The gene-encoding alcohol dehydrogenase used here is the codon-optimized slr1192 (slr1192OP). b Genetic concepts, growth curve, isobutanol titer, SDS-PAGE, and western immunoblot from the engineered strains containing single operon. GOI Gene of interest. KivdS286T and slr1192OP-encoded alcohol dehydrogenase were strep-tagged and the other genes were flag-tagged. BCD is the bicistronic design for providing more reliable expression. c Growth curve, isobutanol titer, SDS-PAGE, and Western blot from the engineered strains containing convergent-oriented operons. KivdS286T was strep-tagged and the other genes were Flag-tagged. RiboJ is a self-cleaving ribozyme for providing more reliable expression. Size of the proteins are: AlsS: 62 kDa, IlvC: 54 kDa, IlvD: 65 kDa, KivdS286T: 61 kDa, Sll1981: 60 kDa, Sll1363: 40 kDa, Slr0452: 59 kDa, Slr1192: 36 kDa, Sll0065: 21 kDa, Slr2088: 68 kDaBack to article page