Improvement of ethanol production from D-lactic acid by constitutive expression of lactate transporter Jen1p in Saccharomyces cerevisiae.

To improve ethanol production from D-lactate, Jen1p, a monocarboxylate-proton symporter, was constitutively expressed in Saccharomyces cerevisiae NAM34-4C. The mutant produced 2.4 g/L of ethanol, approximately 2.4 times higher than that of the wild-type strain. A monocarboxylate/proton symporter gene (JEN1) null mutant was also constructed. It produced 0.19 g/L of ethanol, 5 times lower than that of the wild-type strain.