Metabolic engineering of Saccharomyces cerevisiae for efficient production of pure l−(+)−lactic acid

• DOI: 10.1007/bf02685960
• Publication Date: 2007-08-11T06:23:38Z
• Authors: Nobuhiro Ishida; Satoshi Saitoh; Toru Ohnishi; Kenro Tokuhiro; Eiji Nagamori; Katsuhiko Kitamoto; Haruo Takahashi
• Keywords: 0303 health sciences; L-Lactate Dehydrogenase; Pilot Projects; Saccharomyces cerevisiae; Protein Engineering; Recombinant Proteins; 03 medical and health sciences; Genetic Enhancement; Animals; Feasibility Studies; Cattle; Lactic Acid; Cloning, Molecular; Promoter Regions, Genetic; Pyruvate Decarboxylase

We developed a metabolically engineered Saccharomyces cerevisiae, which produces optically pure L-lactic acid efficiently using cane juice-based medium. In this recombinant, the coding region of pyruvate decarboxylase (PDC)1 was completely deleted, and six copies of the bovine L-lactate dehydrogenase (L-LDH) genes were introduced on the genome under the control of the PDC1 promoter. To confirm optically pure lactate production in low cost medium, cane juice-based medium was used in fermentation with neutralizing conditions. L-lactate production reached 122 g/L, with 61% of sugar being transformed into L-lactate finally. The optical purity of this L-lactate, that affects the physical characteristics of poly-L-lactic acid, was extremely high, 99.9% or over.