FIG 3.

HPLC and NMR confirmation of 1,2-PDO production by dhaT::Ll.LtrB mutant. (A) Detection of a unique HPLC peak in supernatants derived from the dhaT disruption mutant (dhaT::Ll.LtrB) and the dhaT-complemented mutant (dhaT::Ll.LtrB[pMTLdhaT]). The HPLC peak corresponding to the unknown metabolite is shown with black arrows and was found to partially overlap the 1,3-PDO peak. The heights of the 1,3-PDO peaks are proportionate to the 1,3-PDO concentration. (B) Comparison of the unknown metabolite (arrow) and 1,3-PDO HPLC peaks in dhaT::Ll.LtrB mutant culture supernatants with pure standards of 1,2-PDO and 1,3-PDO at concentrations of 0.5 g liter⁻¹ and 1.0 g liter⁻¹, respectively. The heights of the 1,3-PDO peaks are proportionate to 1,3-PDO concentration. (C) NMR resonances of 1,2-PDO used for identification and quantification. Arrows identify specific peaks attributed to 1,2-PDO. Spectra from two replicates of each strain are shown and were compared against a reference 1,2-PDO spectrum (not shown) from a standard chemical library. The chemical shift is depicted in parts per million (ppm) and is based on the change in standard resonance frequency of hydrogen (600 MHz).