3HV biosynthesis solely from glycerol. This figure shows s hake-flask production of chiral 3HV in various knock-out strains as described in Table 1. Cells were grown in LB supplemented with 20 g/L glycerol. The amounts of (S)-3HB produced in both recombinant HCT 10 and HCT 21 strains were too low to be quantified due to a low detection limit by DAD at 210 nm; therefore, the 3HV/3HB ratios were not applicable (NA) to the (S)-isomer. All strains contained the same set of plasmids pET-PB-B, pCOLA-Tecm-Icg, and pCDF-T-H (for (S)-3HV synthesis) or pCDF-T-P (for (R)-3HV synthesis).