Lactic acid production in Saccharomyces cerevisiae is modulated by expression of the monocarboxylate transporters Jen1 and Ady2

Abstract

We aimed to manipulate the metabolism of Saccharomyces cerevisiae to produce lactic acid and search for the potential influence of acid transport across the plasma membrane in this process. Saccharomyces cerevisiae W303-1A is able to use l-lactic acid but its production in our laboratory has not previously been detected. When the l-LDH gene from Lactobacillus casei was expressed in S. cerevisiae W303-1A and in the isogenic mutants jen1∆, ady2∆ and jen1∆ ady2∆, all strains were able to produce lactic acid, but higher titres were achieved in the mutant strains. In strains constitutively expressing both LDH and JEN1 or ADY2, a higher external lactic acid concentration was found when glucose was present in the medium, but when glucose was exhausted, its consumption was more pronounced. These results demonstrate that expression of monocarboxylate permeases influences lactic acid production. Ady2 has been previously characterized as an acetate permease but our results demonstrated its additional role in lactate uptake. Overall, we demonstrate that monocarboxylate transporters Jen1 and Ady2 are modulators of lactic acid production and may well be used to manipulate lactic acid export in yeast cells.

Improvement of Ethanol Production fromD-Lactic Acid by Constitutive Expression of Lactate Transporter Jen1p inSaccharomyces cerevisiae

“…12) We constructed ADY2 mutants, constitutive and null, and found that the mutation did not change the extent of ethanol production from lactate (Tani et al, unpublished results). Thus we have found Jen1p to be the only lactate-transporter necessary for the efficient production of ethanol from D-lactate, even at pH 3.0.…”

Advances in Metabolic Engineering of Saccharomyces cerevisiae for the Production of Industrially and Clinically Important Chemicals

“…In addition, elimination of NADH-consuming reactions through deletions of NDE1 and NDE2 encoding mitochondrial external NADH dehydrogenases was shown to improve lactic acid production due to increased cofactor availability. The yeast strains that expressed JEN1 and ADY2 encoding monocarboxylate permeases constitutively had improved lactic acid production due to higher elux of lactic acid [34]. Recently, screening of a multi-copy genomic DNA library revealed a novel protein (ESBP6) involved in lactic acid adaptation response, although having a low similarity to monocarboxylate permeases [35].…”

“…Further, two successive laboratory evolution experiments for glycine prototrophy and faster growth were performed with this strain. Finally, overexpression of isocitrate lyase, Icl1p, in the evolved strain, resulted Deletion of PDC1 and expression of multiple copies of L-LDH from bovine [30] Inhibition of L-LDH consumption by deletion of DLD1 and JEN1, elimination of ethanol and glycerol production by deleting PDC1, ADH1, GPD1 and GPD2, and improvement of lactic acid tolerance by adaptive evolution and overexpression of HAA1 [31] Overexpression of HXT1 and HXT7 hexose transporters [32] Repression of ethanol production by deleting PDC1 and ADH1 and enhanced acetylCoA supply by the introduction of the genes encoding acetylating acetaldehyde dehydrogenase enzyme from Escherichia coli [33] Enhancement of lactic acid transport by expressing JEN1 and ADY1 [34] Expression of ESBP6, a novel target isolated by screening a multi-copy yeast genomic DNA library [35] in a succinic acid yield of 0.07 mol/mol glucose under aerobic conditions without glycine addition. Metabolic proiling analysis of a succinic acid-producing recombinant S. cerevisiae hinted a metabolic engineering strategy involving expression of a malic acid transporter from Schizosaccharomyces pombe (MAE1) to export succinic acid out of cells [16].…”

Targeting Demalication and Deacetification Methods: The Role of Carboxylic Acids Transporters

“…Later, it was found that the protein Ady2p was vital for acetate transport in acetic acid-grown cells [33]. Jen1p mediates the transport of lactate, pyruvate, acetate and propionate whereas Ady2p mediates the transport of acetate, propionate, formate and lactate, being both induced by non-fermentable carbon sources, and repressed in the presence of glucose [34].…”