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.  

George Kapetanakis received his PhD diploma

On September 30th, George Kapetanakis (on the right in the picture) publicly presented his PhD work and successfully received his diploma. His research dealt with the poorly known process of amino-acid excretion by yeast cells. He characterized two novel amino-acid exporters and showed that these proteins importantly contribute to cross-feeding by yeast of co-cultivated lactic acid bacteria which cannot grow without an external supply of amino acids. G Kapetanakis also showed that the same proteins mediate excretion of amino acids and cross-feeding of lactic acid bacteria by the Ethanol Red yeast strain used in industrial bioethanol production. This observation is important since contamination of fermenters by lactic acid bacteria is a major issue in bioethanol production. We thus proposed in a novel patent of ULB that the utilization of yeast mutants lacking specific amino-acid exporters reduce the risk of contaminations of bioethanol production tanks by lactic acid bacteria. George Kapetanakis has now been hired as Research and Innovation Scientist in the young Paleo startup (see previous post). Congratulations and thanks to George for his scientific achievements and their potential industrial applications, and good luck with the new job in Paleo!  

Welcome to Paleo

The startup company Paleo exploits yeast to produce GMO-free, heme proteins of beef and other animals for plant-based meat alternatives, with the ultimate goal of making food production more ethical and sustainable. Paleo recently moved into the lab space and offices next to our lab in the IBMM (Institute of Molecular Biology and Medicine). We established excellent contacts with the Paleo team members and we look forward to collaborate with them. Welcome to Paleo and great success in the future!

Interuniversity PhD student day

Nadia Guarini, Luis Sousa, Christopher Dereppe and Bruno André participated to the Interuniversity PhD student day organized in Namur last September 9th. As most other PhD students who attended this event, Nadia, Luis and Christopher presented a flash talk and a poster. This PhD student day, which was cancelled the last two previous years, was a big success.

Yeast Genetics meeting in Los Angeles

Nadia Guarini attended the Yeast Genetics meeting 2022 organized at University of California in Los Angeles (August 17–21). She presented a “flash-talk” and a poster about her work on the role of the yeast H+-ATPase (Pma1) in control of TORC1 in yeast. This conference, the first edition of which was organized 40 years ago, is the “premier meeting for students, postdoctoral scholars, research staff, and principal investigators studying various aspects of eukaryotic biology in yeast, a major experimental model for understanding human cell biology and mechanisms of human disease“.

EMBO workshop on “Membrane transporters as essential elements of cellular function and homeostasis”

B. André participated to the EMBO workshop “Membrane transporters as essential elements of cellular function and homeostasis” organized in Chania (Crete) on August 23-27. He was invited to give a presentation entitled “Interlinks between transporters and TORC1”. This wonderful workshop organized by Pr. G. Diallinas gathered many experts studying the 3D structure, function, regulation, links with diseases and other aspects of membrane transporters from various organisms.

Yeasterday meeting in Brussels

On May 13, the group of Isabelle Georis and our laboratory co-organized the “Yeasterday” meeting in Brussels. This annual meeting gathers scientists from the Benelux who use yeast as a model system or a tool in their research. The oral presentations given by young colleagues (PhD students and postdocs) were of top quality. Luis Sousa from our lab had the opportunity to present his work about amino acid excretion by yeast cells. The final plenary lecture was presented by Dr. Isabelle Sagot (CNRS, IBGC, Bordeaux) about the “The cell biology of quiescent yeast”. We thank all speakers, attendees and sponsors (Paelo, Syngulon FNRS, Rocc, aquilabiolabs) for this exciting science sharing day !


Publication in iScience reporting TORC1 activation mediated by plasma membrane H+-ATPases in plant cells

We are pleased to announce the publication in iScience of an article entitled “Plasma membrane H+-ATPases promote TORC1 activation in plant suspension cells“. This study was carried out by Dr. Cecilia Primo in tight collaboration with the group of Pr. François Chaumont (UCLouvain, Belgium). The article reports that similar to what we have shown in yeast (Saliba et al. 2018, 2021), plasma membrane H+-ATPases in plant cells play an important role in regulation of TORC1 (Target Of Rapamycin Complex 1), the kinase complex coordinating cell growth and metabolism. This study opens the perspectives of better understanding the well-established role of these H+ pumps in regulation of plant cell growth and exploiting this new knowledge in biotechnological processes.

Christopher Dereppe obtained a FRIA fellowship

Good news for the end of this year! Christopher Dereppe was informed by the FNRS that he’s among the laureates of the last competition for FRIA fellowships. Christopher obtained a master diploma in Biochemistry and Molecular and Cellular Biology in 2021 at ULB. He did his master thesis work in our lab where he investigated a novel pathway of TORC1 activation in yeast. He will now further investigate the signals and molecular mechanisms of this pathway. Congratulations to him !


71st National Conference of the Hellenic Society of Biochemistry & Molecular Biology

George Kapetanakis and Bruno André attended the 71st National Conference of the Hellenic Society of Biochemistry & Molecular Biology. George K. gave a presentation on his recent work on amino acid export proteins and Bruno A. was invited to give a conference on TOR regulation in yeast.