Modification of metabolic pathways of Saccharomyces cerevisiae by the expression of lactate dehydrogenase and deletion of pyruvate decarboxylase genes for the lactic acid fermentation at low pH value

The Effect of Pyruvate Decarboxylase Gene Knockout inSaccharomyces cerevisiaeonL-Lactic Acid Production

“…Adachi et al also tried to develop a pdc1 pdc5 recombinant expressing bovine L-LDH using 2 mm plasmid, 12) but the fermentation data for the pdc1 pdc5 mutant strain was not presented in detail. In our research, we took a different approach to integrating a heterologous gene into the genome, not using 2 mm plasmid.…”

“…But it was found that NADH reoxidation does not control glycolytic flux during exposure of respiring S. cerevisiae cultures to glucose excess. 11) On the other hand, to increase the metabolic flow from pyruvic acid to lactic acid, a mutant stain, such as the pdc1 pdc5 double mutant 12) or the adh1 mutant strain, 13) has been utilized as the genetic background to obtain an L-LDH gene-expressing yeast. No detailed analysis, however, has been reported, and no remarkable improvement in L-lactic acid production has been observed.…”

Genetic Engineering ofCandida utilisYeast for Efficient Production ofL-Lactic Acid

“…This relatively high optimal temperature is also advantageous because lactic acid at high concentrations easily becomes solidified in the medium due to low solubility. Usually, fermentation of S. cerevisiae and K. lactis is limited at lower temperatures from 30 to 32 C. [5][6][7][9][10][11][12][13][14] The pH value of the medium also appeared to be important for the production of L-lactic acid, since a previous study showed that adjustment of pH was effective for the high expression of PDC in C. utilis.…”

“…When both L-LDH and PDC are expressed simultaneously, the production or yield of L-lactic acid is low, presumably due to the competition for pyruvic acid by the two enzymes. 4) Decreasing PDC activity has been found to boost the production of L-lactic acid in Saccharomyces cerevisiae [4][5][6][7][8] and Kluyveromyces lactis. 9,10) In the case of S. cerevisiae, which is known as a Crabtree-positive yeast, and which has three PDC genes (ScPDC1, ScPDC5, and ScPDC6), reduction/inactivation of PDC activity causes a severe growth defect.…”

Metabolic engineering of Saccharomyces cerevisiae to improve succinic acid production based on metabolic profiling

“…Since genome sequencing of it was completed 1) and genetic manipulation tools have been developed, S. cerevisiae has the potential as a host species for the production of fuel alcohols and chemical building blocks. Recently, the production of organic acids such as lactic acid [2][3][4][5][6][7][8][9][10][11] and malic acid [12][13][14][15] by S. cerevisiae has been examined because S. cerevisiae grows well under low pH conditions. Here, we report a metabolic engineering approach to succinic acid production by S. cerevisiae.…”