Yeast cells can excrete metabolites, in particular amino acids. These compounds can then be used by other microorganisms which can establish mutualistic interaction with yeast. How do yeast cells excrete amino acids remains poorly known. Thanks to a fruitful collaboration with the group of Dr. Isabelle Georis (Labiris, Anderlecht), George Kapetanakis (PhD student supported by FRIA) characterized Aqr1, Qdr2 and Qdr3 as three amino-acid exporters. Importantly, a yeast triple mutant lacking these proteins displays reduced capability of cross-feeding lactic acid bacteria, which cannot grow without an external amino acid supply. This study entitled “Overlapping Roles of Yeast Transporters Aqr1, Qdr2, and Qdr3 in Amino Acid Excretion and Cross-Feeding of Lactic Acid Bacteria” has just been published in the journal “Frontiers in Microbiology”.
Lactic acid bacteria are frequently found as contaminants during biofuel ethanol fermentation processes, and these infections represent a pervasive problem for many companies. As the yeast mutant described in our study provides a potential solution to this industrial problem, ULB has patented it. Furthermore, a proof of concept (POC) project supported by the Région wallonne now allows us to assess the efficiency of our invention under industrial conditions in collaboration with the start-up company Syngulon.
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