Figure 3

Optimization of the 1,2-Propanediol production by exploiting different acetol-reducing enzymes. LH22 and LH23 were constructed which harbored C. beijerinckii and T. brockii. sADH. A) methylglyoxal synthase activities were measured using cell lysate of LH21, LH22, and LH23, showing that mgsA was functionally overexpressed in all three strains. To confirm the functional expression of yqhD, NADPH-dependent methylglyoxal reduction activities were also measured (See Additional file 1: Figure S1 and text in supporting material), although assay method with higher specificity needs to be developed. (B), (C) NADPH- and NADH-dependent acetol reduction activities measured using cell lysates of the wildtype Synechococcus elongatus PCC 7942 and engineered strains that overexpress gldA from E.coli (LH21), adh from C. beijerinckiiadh (LH22), and adh from T. brockiadh (LH23). (D) Acetol and 1,2-Propanediol accumulated by different strains after 10 days of production.