Acronym: EvoSCO

Proiect code 162/31.07.2023

Adaptive laboratory evolution strategies to increase the lipid accumulation process in oleaginous microorganisms and microbial oil production using agroindustrial residues as substrates

Project summary:
Yarrowia lipolytica is a model oleaginous yeast and a potential source of oil. However, the production cost of microbial oil is currently high, due to the low oil productivity. Only polyunsaturated fatty acids are presently produced on a large scale by genetically modified strains of Y. lipolytica.

The aim of this project is to develop Adaptive Laboratory Evolution (ALE) strategies for the generation of hyper-productive oleaginous strains. The methodology will be developed and initially applied to Y. lipolytica and other oleaginous organisms of industrial interest, extending fundamental knowledge regarding evolutionary molecular changes in lipogenesis.

Project objectives:
Y. lipolytica, Rhodosporidium toruloides,and Cunninghamella echinulata will be evolved under alternating nitrogen-limiting conditions, which favor lipid accumulation, and carbon-limiting conditions, which favor the proliferation of high lipid content cells. After several rounds of evolution, enrichment of the population with oleaginous genotypes is expected. The parental strains will be evolved through alternating cultivation under nitrogen-limiting conditions and an artificial selection step, in which the largest colonies grown on a carbon-free medium are used as inoculum for the next round of evolution. Evolved clones will be characterized biochemically. mRNA-seq will be performed to reveal genes differentially expressed between the evolved and the starting strains. Differentially expressed genes will be mined to enrich relevant Gene Ontology categories and their expression signatures will be compared to those of the starting strain to reveal their potential role in lipogenesis. Similar ALE strategies will be developed to other oleaginous microorganisms. In order to ease the transition to the industrial-scale production of microbial oil the evolved strains will be cultivated in lab-scale bioreactors using selected agro-industrial residues as substrates.