Fig. 8
Performance of the YSM046 (evolved PDCΔ) strain expressing genes in the 2,3-BDO biosynthetic pathway. Lp, Lactobacillus plantarum; Ll, Lactococcus lactis. Op, codon optimized. One or two genes encoding high-activity ALS (alsLpOp) and/or ALDC (aldcLlOp) were expressed in the YSM046 strain (YHI010 and YHI011; gray bars). Three genes encoding high-activity ALS (alsLpOp), ALDC (aldcLlOp) and BDH (BDH1 from S. cerevisiae) were also expressed in the YSM046 strain (YHI030; black bars). As a comparative control, the three genes (alsLpOp, aldcLlOp and BDH1) were expressed in the YPH499 wild-type strain (YHI027; white bars). The pATP422 and pAT425 vectors were used for expressing the ALS (alsLpOp), ALDC (aldcLlOp) and BDH (BDH1) genes. Fermentation experiments were performed in test tubes containing 5 mL of SD selection medium (20 g L−1 glucose) under semi-aerobic conditions. Metabolite concentrations in the medium were determined at 96 h after the start of fermentation. Data are presented as the mean ± standard deviation of three independent transformants (n = 3 each)