Lundi, 14 octobre⋅13:00
Séminaire Thomas Gassler
Institute of Microbiology, ETH Zurich, 8093 Zurich, Switzerland
Advancing traits in fungi by genetic engineering and bacterial implantation
In the projects presented, I summarize recent progress in the implementation of novel properties of different fungal species. These include the conversion of a heterotrophic yeast into an autotroph and a free-living filamentous fungus into a facultative host harboring an endosymbiont. The methylotrophic yeast Pichia pastoris is widely used in the production of industrial enzymes and is being explored as a potential source of nutritional protein. Like most biotechnological production hosts, P. pastoris is heterotrophic and grows on organic feedstocks that have competing uses in food and feed production. As a step toward more sustainable industrial processes, we transformed P. pastoris into an autotroph that grows on CO2 and produces chemicals. By adding eight heterologous genes and deleting three native genes, we engineered the peroxisomal methanol assimilation pathway of P. pastoris into a modified Calvin-Benson-Bassham (CBB) cycle, the predominant natural CO2 fixation pathway. Adaptive laboratory evolution further improved autotrophic growth with mutations that facilitate peroxisomal transport, stabilize the CBB cycle and balance NADH supply. We further showcase bioproduction of the building blocks lactic and itaconic acid from CO2. In the second part, I will present work on the establishment of artificial eukaryote-prokaryote interactions to investigate the early stages of endosymbiogenesis. We use fluidic force microscopy to transplant bacteria from the Burkholderiaceae family into the filamentous fungus Rhizopus microsporus. The introduced bacteria were capable of vertical transmission across fungal generations, and adaptive laboratory evolution was employed to alleviate initial host fitness constraints. Genetic and transcriptomic analyses further elucidated fitness dynamics, providing a better understanding of the balance between mutualism and antagonism in these engineered systems. We further demonstrate the successful transfer of metabolic functions to the novel fungal host, as evidenced by the production of rhizoxin following the introduction of Mycetohabitans rhizoxinica as a novel endosymbiont.
Jeudi, 24 octobre⋅13:00
Séminaire Prof Sihui Yang
Jeudi, 7 novembre⋅13:00
Séminaire David-Camilo Corrales-Munoz
Jeudi, 5 décembre⋅13:00
Séminaire Julien Vaubourgeix
Jeudi, 19 décembre⋅08:30 à 10:30
🎄 Petit-déjeuner de Nöel
