Lactic acid production from xylose by engineered Saccharomyces cerevisiae without PDC or ADH deletion

摘要: Production of lactic acid from renewable sugars has received growing attention as can be used for making and bio-based plastics. However, most prior studies have focused on production glucose despite that cellulosic hydrolysates contain xylose well glucose. Microbial strains capable fermenting both into are needed sustainable economic production. In this study, we introduced a acid-producing pathway an engineered Saccharomyces cerevisiae xylose. Specifically, ldhA the fungi Rhizopus oryzae was overexpressed under control PGK1 promoter through integration expression cassette in chromosome. The resulting strain exhibited high lactate dehydrogenase activity produced or Interestingly, observed substrate-dependent product formation. When yeast cultured glucose, major fermentation ethanol while minor product. contrast, almost exclusively when oxygen-limited conditions. yields were 0.31 g ethanol/g 0.22 acid/g respectively. On xylose, <0.01 0.69 These results demonstrate with yield by S. without deleting pyruvate decarboxylase, formation patterns fermentations altered substrates.