Engineering of fatty acid biosynthesis in Ashbya gossypii for advanced fuels production

Increasing concerns on climate change and other environmental problems have attracted much interest in developing bio-based processes for the production of chemicals, fuels and materials from renewable non-food biomass. Microbial oils represent a sustainable alternative to vegetable oils and animal fats as feedstock for both the chemical and biofuel industries. Moreover, they are a promising alternative to the undesired, limited and pollutants fossil oils.

Our research is focused on the industrial fungus Ashbya gossypii as a model organism to produce oils for the industry. In order to achieve our objectives, we developed for this fungus systems metabolic engineering methods encompassing genetic and protein engineering techniques, synthetic biology and systems biology methods together with the predictive capacity of mathematical models of its metabolism. Following this approach, we constructed a strain capable of accumulating up to 70% of its cell dry weight as lipids. For this purpose we combined the heterologous expression of genes from Yarrowia lipolytica -a well-known lipogenic yeast-, the overexpression of native genes involved in lipid synthesis, and the blocking of the pathway leading to the catabolism of intracellular oils. Furthermore, we generated a wide range of engineered strains able to produce different fatty acid profiles, by engineering the fatty acid elongase and desaturase systems of the fungus. The engineered strains resulted to be good candidates to produce polyunsaturated fatty acids with different biotechnological applications such as waxes, lubricants and biodiesels.