Redesign of Metabolic Pathways for High Yield Production of ?-Carotene in Yarrowia Lipolytica

Biotechnological synthesis of β-carotene for its nutraceutical and antioxidant properties is becoming more attractive and aims to enhance the production using novel recombinant β-carotene producing yeast strains. The use of the engineered yeast Yarrowia lipolytica as a competitive producer organism of β-carotene, is the current method to naturally sustain the high supply of β-carotene in large-scale fermentative production. Towards this goal, we performed several simulations for the identification of competitive in silico strains of Y. lipolytica because of selected simulated in gene deletions within its metabolic network, which was adapted to mimic an engineered yeast capable of producing β-carotene. The design BioCad algorithm is then able to explore the solution space of the problem, defined by all the possible combinations of gene deletions, optimizing multiple objectives such as growth rate, target production or productivity as predicted by the flux balance analysis. The framework, based on an ad-hoc optimization algorithm for the consequential selection of the notable gene deletions, identifies the most promising sub-optimal strains within the Pareto Fronts. The strains selected by the procedure undergo further characterization, such as a selection of strains with the more appropriate genes to be deleted at the same time, with a more efficient usage of nutrients or with less waste metabolites produced. Our pipeline for in silico identification of competitive strains of engineered Y. lipolytica through the selection of effective gene deletions that can test and rank a high number of candidates. This approach is effective for the optimization of the design of competitive strains and is also helpful for accelerate the experimental processes of predicted mutants in vitro. β-carotene production was obtained on a wide range of different media and with different combinations of carbon sources.