Microorganisms and processes for lactic acid production

A genetically engineered yeast strain of genus Kluyveromyces to produce lactic acid comprising a chromosomally integrated gene that encodes an exogenous lactate dehydrogenase, wherein said yeast strain produces lactic acid in a fermentation production medium with an average specific productivity of at least 1.875 g/L-hr, and wherein said fermentation production medium has a final pH that is lower than 3.86, wherein said gene that encodes an exogenous lactate dehydrogenase is integrated at least at one chromosomal locus selected from a group consisting of a pyruvate decarboxylase gene, a phosphoenolpyruvate carboxykinase gene, a glycerol-3-phosphate phosphatase gene, and a NADH dehydrogenase 1 gene.