Enhanced d-lactic acid production by recombinant Saccharomyces cerevisiae following optimization of the global metabolic pathway.

Utilization of renewable feedstocks for the production of bio-based chemicals such as d-lactic acid by engineering metabolic pathways in the yeast Saccharomyces cerevisiae has recently become an attractive option. In this study, to realize efficient d-lactic acid production by S. cerevisiae, the expression of 12 glycolysis-related genes and the Leuconostoc mesenteroides d-LDH gene was optimized using a previously developed global metabolic engineering strategy, and repeated batch fermentation was carried out using the resultant strain YPH499/dPdA3-34/DLDH/1-18. Stable d-lactic acid production through 10 repeated batch fermentations was achieved using YPH499/dPdA3-34/DLDH/1-18. The average d-lactic acid production, productivity, and yield with 10 repeated batch fermentations were 60.3 g/L, 2.80 g/L/h, and 0.646, respectively. The present study is the first report of the application of a global metabolic engineering strategy for bio-based chemical production, and it shows the potential for efficient production of such chemicals by global metabolic engineering of the yeast S. cerevisiae. Biotechnol. Bioeng. 2017;114: 2075-2084.