The dicarboxylate transporters from the AceTr family and Dct-02 oppositely affect succinic acid production in S. cerevisiae

Membrane transporters are important targets in metabolic engineering to establish and improve the production of chemicals such as succinic acid from renewable resources by microbial cell factories. We recently provided a Saccharomyces cerevisiae strain able to strongly overproduce succinic acid from glycerol and CO2 in which the Dct-02 transporter from Aspergillus niger, assumed to be an anion channel, was used to export succinic acid from the cells. In a different study, we reported a new group of succinic acid transporters from the AceTr family, which were also described as anion channels. Here, we expressed these transporters in a succinic acid overproducing strain and compared their impact on extracellular succinic acid accumulation with that of the Dct-02 transporter. The results show that the tested transporters of the AceTr family hinder succinic acid accumulation in the extracellular medium at low pH, which is in strong contrast to Dct-02. Data suggests that the AceTr transporters prefer monovalent succinate, whereas Dct-02 prefers divalent succinate anions. In addition, the results provided deeper insights into the characteristics of Dct-02, showing its ability to act as a succinic acid importer (thus being bidirectional) and verifying its capability of exporting malate.This research was funded by European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Yeastdoc grant agreement No 764927, by the strategic program UID/BIA/04050/2020 and the project LA/P/0069/2020 granted to the Associate Laboratory ARNET, funded by Portuguese funds through the FCT I.P., and by River2Ocean NORTE-01-0145- FEDER-000068, co-financed by the European Regional Development Fund (ERDF) through Programa Operacional Regional do Norte (NORTE 2020). I.S-S. was supported by the program contract FCTUMINHO/Norma transitória from the Legal Regime of Scientific Employment (RJEC)