Publication reporting improvement of a bioethanol-producing yeast strain by loss of QDR amino-acid exporter genes

We are pleased to announce the publication in Scientific Reports of an article entitled “Deletion of QDR genes in a bioethanol‐producing yeast strain reduces propagation of contaminating lactic acid bacteria“. This study reports that the yeast Ethanol Red strain commonly used to produce bioethanol excretes amino acids via Qdr membrane transporters. This excretion favors propagation of co-cultivated lactic acid bacteria, which cannot grow without an external supply of amino acids. A derivative yeast mutant in which QDR genes have been deleted via CRISPR-Cas9 displays markedly reduced cross-feeding of these bacteria without reduction of ethanol production. Given that bacterial contaminations in yeast fermentation tanks are a recurring problem for the bioethanol production industry, this finding opens the perspective of using yeast strains with mutations in QDR genes to reduce the risk of such contaminations. This study, which has been mainly conducted by Dr. George Kapetanakis during his PhD work, is the result of a fruitful collaboration with Dr. Isabelle Georis (Labiris), Dr. LaurenceVan Nedervelde (Labiris), and the “Syngulon” startup company.